Cosmology - Blog Posts

Matter cannot be created or destroyed.

that's the rule of the universe.

You've always existed in some way.

and no matter how many times you get blown apart;

The gravity of your atoms will drag you back together.

Tearing your self apart is futile.

It's nuclear fission.

You only salt the earth in your despair.

Tear open the black hole just for the gravity well to drag you under.

The only escape is expansion.

A Tour of Cosmic Temperatures

We often think of space as “cold,” but its temperature can vary enormously depending on where you visit. If the difference between summer and winter on Earth feels extreme, imagine the range of temperatures between the coldest and hottest places in the universe — it’s trillions of degrees! So let’s take a tour of cosmic temperatures … from the coldest spots to the hottest temperatures yet achieved.

First, a little vocabulary: Astronomers use the Kelvin temperature scale, which is represented by the symbol K. Going up by 1 K is the same as going up 1°C, but the scale begins at 0 K, or -273°C, which is also called absolute zero. This is the temperature where the atoms in stuff stop moving. We’ll measure our temperatures in this tour in kelvins, but also convert them to make them more familiar!

We’ll start on the chilly end of the scale with our CAL (Cold Atom Lab) on the International Space Station, which can chill atoms to within one ten billionth of a degree above 0 K, just a fraction above absolute zero.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Just slightly warmer is the Resolve sensor inside XRISM, pronounced “crism,” short for the X-ray Imaging and Spectroscopy Mission. This is an international collaboration led by JAXA (Japan Aerospace Exploration Agency) with NASA and ESA (European Space Agency). Resolve operates at one twentieth of a degree above 0 K. Why? To measure the heat from individual X-rays striking its 36 pixels!

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Resolve and CAL are both colder than the Boomerang Nebula, the coldest known region in the cosmos at just 1 K! This cloud of dust and gas left over from a Sun-like star is about 5,000 light-years from Earth. Scientists are studying why it’s colder than the natural background temperature of deep space.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Let’s talk about some temperatures closer to home. Icy gas giant Neptune is the coldest major planet. It has an average temperature of 72 K at the height in its atmosphere where the pressure is equivalent to sea level on Earth. Explore how that compares to other objects in our solar system!

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

How about Earth? According to NOAA, Death Valley set the world’s surface air temperature record on July 10, 1913. This record of 330 K has yet to be broken — but recent heat waves have come close. (If you’re curious about the coldest temperature measured on Earth, that’d be 183.95 K (-128.6°F or -89.2°C) at Vostok Station, Antarctica, on July 21, 1983.)

We monitor Earth's global average temperature to understand how our planet is changing due to human activities. Last year, 2023, was the warmest year on our record, which stretches back to 1880.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

The inside of our planet is even hotter. Earth’s inner core is a solid sphere made of iron and nickel that’s about 759 miles (1,221 kilometers) in radius. It reaches temperatures up to 5,600 K.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

We might assume stars would be much hotter than our planet, but the surface of Rigel is only about twice the temperature of Earth’s core at 11,000 K. Rigel is a young, blue star in the constellation Orion, and one of the brightest stars in our night sky.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger 

We study temperatures on large and small scales. The electrons in hydrogen, the most abundant element in the universe, can be stripped away from their atoms in a process called ionization at a temperature around 158,000 K. When these electrons join back up with ionized atoms, light is produced. Ionization is what makes some clouds of gas and dust, like the Orion Nebula, glow.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

We already talked about the temperature on a star’s surface, but the material surrounding a star gets much, much hotter! Our Sun’s surface is about 5,800 K (10,000°F or 5,500°C), but the outermost layer of the solar atmosphere, called the corona, can reach millions of kelvins.

Our Parker Solar Probe became the first spacecraft to fly through the corona in 2021, helping us answer questions like why it is so much hotter than the Sun's surface. This is one of the mysteries of the Sun that solar scientists have been trying to figure out for years.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Looking for a hotter spot? Located about 240 million light-years away, the Perseus galaxy cluster contains thousands of galaxies. It’s surrounded by a vast cloud of gas heated up to tens of millions of kelvins that glows in X-ray light. Our telescopes found a giant wave rolling through this cluster’s hot gas, likely due to a smaller cluster grazing it billions of years ago.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Now things are really starting to heat up! When massive stars — ones with eight times the mass of our Sun or more — run out of fuel, they put on a show. On their way to becoming black holes or neutron stars, these stars will shed their outer layers in a supernova explosion. These layers can reach temperatures of 300 million K!

Credit: NASA's Goddard Space Flight Center/Jeremy Schnittman

We couldn’t explore cosmic temperatures without talking about black holes. When stuff gets too close to a black hole, it can become part of a hot, orbiting debris disk with a conical corona swirling above it. As the material churns, it heats up and emits light, making it glow. This hot environment, which can reach temperatures of a billion kelvins, helps us find and study black holes even though they don’t emit light themselves.

JAXA’s XRISM telescope, which we mentioned at the start of our tour, uses its supercool Resolve detector to explore the scorching conditions around these intriguing, extreme objects.

Credit: NASA's Goddard Space Flight Center/CI Lab

Our universe’s origins are even hotter. Just one second after the big bang, our tiny, baby universe consisted of an extremely hot — around 10 billion K — “soup” of light and particles. It had to cool for a few minutes before the first elements could form. The oldest light we can see, the cosmic microwave background, is from about 380,000 years after the big bang, and shows us the heat left over from these earlier moments.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

We’ve ventured far in distance and time … but the final spot on our temperature adventure is back on Earth! Scientists use the Large Hadron Collider at CERN to smash teensy particles together at superspeeds to simulate the conditions of the early universe. In 2012, they generated a plasma that was over 5 trillion K, setting a world record for the highest human-made temperature.

Want this tour as a poster? You can download it here in a vertical or horizontal version!

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

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Observations from both NASA’s James Webb and Hubble space telescopes created this colorful image of galaxy cluster MACS0416. The colors of different galaxies indicate distances, with bluer galaxies being closer and redder galaxies being more distant or dusty. Some galaxies appear as streaks due to gravitational lensing — a warping effect caused by large masses gravitationally bending the space that light travels through.

Like Taylor Swift, Our Universe Has Gone Through Many Different Eras

While Taylor's Eras Tour explores decades of music, our universe’s eras set the stage for life to exist today. By unraveling cosmic history, scientists can investigate how it happened, from the universe’s origin and evolution to its possible fate.

This infographic outlines the history of the universe.

0 SECONDS | In the beginning, the universe debuted extremely small, hot, and dense

Scientists aren’t sure what exactly existed at the very beginning of the universe, but they think there wasn’t any normal matter or physics. Things probably didn’t behave like we expect them to today.

Artist's interpretation of the beginning of the universe, with representations of the early cosmos and its expansion.

10^-32 SECONDS | The universe rapidly, fearless-ly inflated

When the universe debuted, it almost immediately became unstable. Space expanded faster than the speed of light during a very brief period known as inflation. Scientists are still exploring what drove this exponential expansion.

1 MICROSECOND | Inflation’s end started the story of us: we wouldn’t be here if inflation continued

When inflation ended, the universe continued to expand, but much slower. All the energy that previously drove the rapid expansion went into light and matter — normal stuff! Small subatomic particles — protons, neutrons, and electrons — now floated around, though the universe was too hot for them to combine and form atoms.

The particles gravitated together, especially in clumpy spots. The push and pull between gravity and the particles’ inability to stick together created oscillations, or sound waves.

Artist's interpretation of protons and neutrons colliding to form ionized deuterium — a hydrogen isotope with one proton and one neutron — and ionized helium — two protons and two neutrons.

THREE MINUTES | Protons and neutrons combined all too well

After about three minutes, the universe had expanded and cooled enough for protons and neutrons to stick together. This created the very first elements: hydrogen, helium, and very small amounts of lithium and beryllium.

But it was still too hot for electrons to combine with the protons and neutrons. These free electrons floated around in a hot foggy soup that scattered light and made the universe appear dark.

This animated artist’s concept begins by showing ionized atoms (red blobs), free electrons (green blobs), and photons of light (blue flashes). The ionized atoms scattered light until neutral atoms (shown as brown blobs) formed, clearing the way for light to travel farther through space.

380 THOUSAND YEARS | Neutral atoms formed and left a blank space for light

As the universe expanded and cooled further, electrons joined atoms and made them neutral. With the electron plasma out of the way, some light could travel much farther.

An image of the cosmic microwave background (CMB) across the entire sky, taken by ESA's (European Space Agency) Planck space telescope. The CMB is the oldest light we can observe in the universe. Frozen sound waves are visible as miniscule fluctuations in temperature, shown through blue (colder) and red (warmer) coloring.

As neutral atoms formed, the sound waves created by the push and pull between subatomic particles stopped. The waves froze, leaving ripples that were slightly denser than their surroundings. The excess matter attracted even more matter, both normal and “dark.” Dark matter has gravitational influence on its surroundings but is invisible and does not interact with light.

This animation illustrates the absorption of photons — light particles — by neutral hydrogen atoms.

ALSO 380 THOUSAND YEARS | The universe became dark — call it what you want, but scientists call this time period the Dark Ages 

Other than the cosmic microwave background, there wasn't much light during this era since stars hadn’t formed yet. And what light there was usually didn't make it very far since neutral hydrogen atoms are really good at absorbing light. This kicked off an era known as the cosmic dark ages.

This animation illustrates the beginning of star formation as gas begins to clump due to gravity. These protostars heat up as material compresses inside them and throw off material at high speeds, creating shockwaves shown here as expanding rings of light.

200 MILLION YEARS | Stars created daylight (that was still blocked by hydrogen atoms)

Over time, denser areas pulled in more and more matter, in some places becoming so heavy it triggered a collapse. When the matter fell inward, it became hot enough for nuclear fusion to start, marking the birth of the first stars!

A simulation of dark matter forming structure due to gravity.

400 MILLION YEARS | Dark matter acted like an invisible string tying galaxies together

As the universe expanded, the frozen sound waves created earlier — which now included stars, gas, dust, and more elements produced by stars — stretched and continued attracting more mass. Pulling material together eventually formed the first galaxies, galaxy clusters, and wide-scale, web-like structure. 

In this animation, ultraviolet light from stars ionizes hydrogen atoms by breaking off their electrons. Regions already ionized are blue and translucent, areas undergoing ionization are red and white, and regions of neutral gas are dark and opaque.

1 BILLION YEARS | Ultraviolet light from stars made the universe transparent for evermore

The first stars were massive and hot, meaning they burned their fuel supplies quickly and lived short lives. However, they gave off energetic ultraviolet light that helped break apart the neutral hydrogen around the stars and allowed light to travel farther.

Animation showing a graph of the universe’s expansion over time. While cosmic expansion slowed following the end of inflation, it began picking up the pace around 5 billion years ago. Scientists still aren't sure why.

SOMETIME AFTER 10 BILLION YEARS | Dark energy became dominant, accelerating cosmic expansion and creating a big question…?

By studying the universe’s expansion rate over time, scientists made the shocking discovery that it’s speeding up. They had thought eventually gravity should cause the matter to attract itself and slow down expansion. Some mysterious pressure, dubbed dark energy, seems to be accelerating cosmic expansion. About 10 billion years into the universe’s story, dark energy – whatever it may be – became dominant over matter.

An image of Earth rising in the Moon’s sky. Nicknamed “Earthrise,” Apollo 8 astronauts saw this sight during the first crewed mission to the Moon.

13.8 BILLION YEARS | The universe as we know it today: 359,785,714,285.7 fortnights from the beginning

We owe our universe today to each of its unique stages. However, scientists still have many questions about these eras.

Our upcoming Nancy Grace Roman Space Telescope will look back in time to explore cosmic mysteries like dark energy and dark matter – two poorly understood aspects of the universe that govern its evolution and ultimate fate.

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A simulated image of NASA’s Nancy Grace Roman Space Telescope’s future observations toward the center of our galaxy, spanning less than 1 percent of the total area of Roman’s Galactic Bulge Time-Domain Survey. The simulated stars were drawn from the Besançon Galactic Model.

Exploring the Changing Universe with the Roman Space Telescope

The view from your backyard might paint the universe as an unchanging realm, where only twinkling stars and nearby objects, like satellites and meteors, stray from the apparent constancy. But stargazing through NASA’s upcoming Nancy Grace Roman Space Telescope will offer a front row seat to a dazzling display of cosmic fireworks sparkling across the sky.

Roman will view extremely faint infrared light, which has longer wavelengths than our eyes can see. Two of the mission’s core observing programs will monitor specific patches of the sky. Stitching the results together like stop-motion animation will create movies that reveal changing objects and fleeting events that would otherwise be hidden from our view.

Watch this video to learn about time-domain astronomy and how time will be a key element in NASA’s Nancy Grace Roman Space Telescope’s galactic bulge survey. Credit: NASA’s Goddard Space Flight Center

This type of science, called time-domain astronomy, is difficult for telescopes that have smaller views of space. Roman’s large field of view will help us see huge swaths of the universe. Instead of always looking at specific things and events astronomers have already identified, Roman will be able to repeatedly observe large areas of the sky to catch phenomena scientists can't predict. Then astronomers can find things no one knew were there!

One of Roman’s main surveys, the Galactic Bulge Time-Domain Survey, will monitor hundreds of millions of stars toward the center of our Milky Way galaxy. Astronomers will see many of the stars appear to flash or flicker over time.

This animation illustrates the concept of gravitational microlensing. When one star in the sky appears to pass nearly in front of another, the light rays of the background source star are bent due to the warped space-time around the foreground star. The closer star is then a virtual magnifying glass, amplifying the brightness of the background source star, so we refer to the foreground star as the lens star. If the lens star harbors a planetary system, then those planets can also act as lenses, each one producing a short change in the brightness of the source. Thus, we discover the presence of each exoplanet, and measure its mass and how far it is from its star. Credit: NASA's Goddard Space Flight Center Conceptual Image Lab 

That can happen when something like a star or planet moves in front of a background star from our point of view. Because anything with mass warps the fabric of space-time, light from the distant star bends around the nearer object as it passes by. That makes the nearer object act as a natural magnifying glass, creating a temporary spike in the brightness of the background star’s light. That signal lets astronomers know there’s an intervening object, even if they can’t see it directly.

This artist’s concept shows the region of the Milky Way NASA’s Nancy Grace Roman Space Telescope’s Galactic Bulge Time-Domain Survey will cover – relatively uncharted territory when it comes to planet-finding. That’s important because the way planets form and evolve may be different depending on where in the galaxy they’re located. Our solar system is situated near the outskirts of the Milky Way, about halfway out on one of the galaxy’s spiral arms. A recent Kepler Space Telescope study showed that stars on the fringes of the Milky Way possess fewer of the most common planet types that have been detected so far. Roman will search in the opposite direction, toward the center of the galaxy, and could find differences in that galactic neighborhood, too.

Using this method, called microlensing, Roman will likely set a new record for the farthest-known exoplanet. That would offer a glimpse of a different galactic neighborhood that could be home to worlds quite unlike the more than 5,500 that are currently known. Roman’s microlensing observations will also find starless planets, black holes, neutron stars, and more!

This animation shows a planet crossing in front of, or transiting, its host star and the corresponding light curve astronomers would see. Using this technique, scientists anticipate NASA’s Nancy Grace Roman Space Telescope could find 100,000 new worlds. Credit: NASA’s Goddard Space Flight Center/Chris Smith (USRA/GESTAR)

Stars Roman sees may also appear to flicker when a planet crosses in front of, or transits, its host star as it orbits. Roman could find 100,000 planets this way! Small icy objects that haunt the outskirts of our own solar system, known as Kuiper belt objects, may occasionally pass in front of faraway stars Roman sees, too. Astronomers will be able to see how much water the Kuiper belt objects have because the ice absorbs specific wavelengths of infrared light, providing a “fingerprint” of its presence. This will give us a window into our solar system’s early days.

This animation visualizes a type Ia supernova.

Roman’s High Latitude Time-Domain Survey will look beyond our galaxy to hunt for type Ia supernovas. These exploding stars originate from some binary star systems that contain at least one white dwarf – the small, hot core remnant of a Sun-like star. In some cases, the dwarf may siphon material from its companion. This triggers a runaway reaction that ultimately detonates the thief once it reaches a specific point where it has gained so much mass that it becomes unstable.

NASA’s upcoming Nancy Grace Roman Space Telescope will see thousands of exploding stars called supernovae across vast stretches of time and space. Using these observations, astronomers aim to shine a light on several cosmic mysteries, providing a window onto the universe’s distant past. Credit: NASA’s Goddard Space Flight Center

Since these rare explosions each peak at a similar, known intrinsic brightness, astronomers can use them to determine how far away they are by simply measuring how bright they appear. Astronomers will use Roman to study the light of these supernovas to find out how quickly they appear to be moving away from us.

By comparing how fast they’re receding at different distances, scientists can trace cosmic expansion over time. This will help us understand whether and how dark energy – the unexplained pressure thought to speed up the universe’s expansion – has changed throughout the history of the universe.

NASA’s Nancy Grace Roman Space Telescope will survey the same areas of the sky every few days. Researchers will mine this data to identify kilonovas – explosions that happen when two neutron stars or a neutron star and a black hole collide and merge. When these collisions happen, a fraction of the resulting debris is ejected as jets, which move near the speed of light. The remaining debris produces hot, glowing, neutron-rich clouds that forge heavy elements, like gold and platinum. Roman’s extensive data will help astronomers better identify how often these events occur, how much energy they give off, and how near or far they are.

And since this survey will repeatedly observe the same large vista of space, scientists will also see sporadic events like neutron stars colliding and stars being swept into black holes. Roman could even find new types of objects and events that astronomers have never seen before!

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Black Hole Friday Deals!

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Galactic 5-for-1 special! Learn more about Stephan’s Quintet.

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Standard candles: Exploding stars that are reliably bright. Multi-functional — can be used to measure distances in space!

Feed the black hole in your stomach. Spaghettification’s on the menu.

Act quickly before the stars in this widow system are gone!

Add some planets to your solar system! Grab our Exoplanet Bundle.

Get ready to ride this (gravitational) wave before this Black Hole Merger ends!

Be the center of attention in this stylish accretion disk skirt. Made of 100% recycled cosmic material.

Should you ever travel to a black hole? No. But if you do, here’s a free guide to make your trip as safe* as possible. *Note: black holes are never safe. 

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Astronomers used three of NASA's Great Observatories to capture this multiwavelength image showing galaxy cluster IDCS J1426.5+3508. It includes X-rays recorded by the Chandra X-ray Observatory in blue, visible light observed by the Hubble Space Telescope in green, and infrared light from the Spitzer Space Telescope in red. This rare galaxy cluster has important implications for understanding how these megastructures formed and evolved early in the universe.

How Astronomers Time Travel

Let’s add another item to your travel bucket list: the early universe! You don’t need the type of time machine you see in sci-fi movies, and you don’t have to worry about getting trapped in the past. You don’t even need to leave the comfort of your home! All you need is a powerful space-based telescope.

But let’s start small and work our way up to the farthest reaches of space. We’ll explain how it all works along the way.

This animation illustrates how fast light travels between Earth and the Moon. The farther light has to travel, the more noticeable its speed limit becomes.

The speed of light is superfast, but it isn’t infinite. It travels at about 186,000 miles (300 million meters) per second. That means that it takes time for the light from any object to reach our eyes. The farther it is, the more time it takes.

You can see nearby things basically in real time because the light travel time isn’t long enough to make a difference. Even if an object is 100 miles (161 kilometers) away, it takes just 0.0005 seconds for light to travel that far. But on astronomical scales, the effects become noticeable.

This infographic shows how long it takes light to travel to different planets in our solar system.

Within our solar system, light’s speed limit means it can take a while to communicate back and forth between spacecraft and ground stations on Earth. We see the Moon, Sun, and planets as they were slightly in the past, but it's not usually far enough back to be scientifically interesting.

As we peer farther out into our galaxy, we use light-years to talk about distances. Smaller units like miles or kilometers would be too overwhelming and we’d lose a sense of their meaning. One light-year – the distance light travels in a year – is nearly 6 trillion miles (9.5 trillion kilometers). And that’s just a tiny baby step into the cosmos.

The Sun’s closest neighboring star, Proxima Centauri, is 4.2 light-years away. That means we see it as it was about four years ago. Betelgeuse, a more distant (and more volatile) stellar neighbor, is around 700 light-years away. Because of light’s lag time, astronomers don’t know for sure whether this supergiant star is still there! It may have already blasted itself apart in a supernova explosion – but it probably has another 10,000 years or more to go.

What looks much like craggy mountains on a moonlit evening is actually the edge of a nearby, young, star-forming region NGC 3324 in the Carina Nebula. Captured in infrared light by the Near-Infrared Camera (NIRCam) on NASA’s James Webb Space Telescope, this image reveals previously obscured areas of star birth.

The Carina Nebula clocks in at 7,500 light-years away, which means the light we receive from it today began its journey about 3,000 years before the pyramids of Giza in Egypt were built! Many new stars there have undoubtedly been born by now, but their light may not reach Earth for thousands of years.

An artist’s concept of our Milky Way galaxy, with rough locations for the Sun and Carina nebula marked.

If we zoom way out, you can see that 7,500 light-years away is still pretty much within our neighborhood. Let’s look further back in time…

This stunning image by the NASA/ESA Hubble Space Telescope features the spiral galaxy NGC 5643. Looking this good isn’t easy; 30 different exposures, for a total of nine hours of observation time, together with Hubble’s high resolution and clarity, were needed to produce an image of such exquisite detail and beauty.

Peering outside our Milky Way galaxy transports us much further into the past. The Andromeda galaxy, our nearest large galactic neighbor, is about 2.5 million light-years away. And that’s still pretty close, as far as the universe goes. The image above shows the spiral galaxy NGC 5643, which is about 60 million light-years away! That means we see it as it was about 60 million years ago.

As telescopes look deeper into the universe, they capture snapshots in time from different cosmic eras. Astronomers can stitch those snapshots together to unravel things like galaxy evolution. The closest ones are more mature; we see them nearly as they truly are in the present day because their light doesn’t have to travel as far to reach us. We can’t rewind those galaxies (or our own), but we can get clues about how they likely developed. Looking at galaxies that are farther and farther away means seeing these star cities in ever earlier stages of development.

The farthest galaxies we can see are both old and young. They’re billions of years old now, and the light we receive from them is ancient since it took so long to traverse the cosmos. But since their light was emitted when the galaxies were young, it gives us a view of their infancy.

This animation is an artist’s concept of the big bang, with representations of the early universe and its expansion.

Comparing how fast objects at different distances are moving away opened up the biggest mystery in modern astronomy: cosmic acceleration. The universe was already expanding as a result of the big bang, but astronomers expected it to slow down over time. Instead, it’s speeding up!

The universe’s expansion makes it tricky to talk about the distances of the farthest objects. We often use lookback time, which is the amount of time it took for an object’s light to reach us. That’s simpler than using a literal distance, because an object that was 10 billion light-years away when it emitted the light we received from it would actually be more than 16 billion light-years away right now, due to the expansion of space. We can even see objects that are presently over 30 billion light-years from Earth, even though the universe is only about 14 billion years old.

This James Webb Space Telescope image shines with the light from galaxies that are more than 13.4 billion years old, dating back to less than 400 million years after the big bang.

Our James Webb Space Telescope has helped us time travel back more than 13.4 billion years, to when the universe was less than 400 million years old. When our Nancy Grace Roman Space Telescope launches in a few years, astronomers will pair its vast view of space with Webb’s zooming capabilities to study the early universe in better ways than ever before. And don’t worry – these telescopes will make plenty of pit stops along the way at other exciting cosmic destinations across space and time.

Learn more about the exciting science Roman will investigate on X and Facebook.

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Caution: Universe Work Ahead 🚧

We only have one universe. That’s usually plenty – it’s pretty big after all! But there are some things scientists can’t do with our real universe that they can do if they build new ones using computers.

The universes they create aren’t real, but they’re important tools to help us understand the cosmos. Two teams of scientists recently created a couple of these simulations to help us learn how our Nancy Grace Roman Space Telescope sets out to unveil the universe’s distant past and give us a glimpse of possible futures.

Caution: you are now entering a cosmic construction zone (no hard hat required)!

This simulated Roman deep field image, containing hundreds of thousands of galaxies, represents just 1.3 percent of the synthetic survey, which is itself just one percent of Roman's planned survey. The full simulation is available here. The galaxies are color coded – redder ones are farther away, and whiter ones are nearer. The simulation showcases Roman’s power to conduct large, deep surveys and study the universe statistically in ways that aren’t possible with current telescopes.

One Roman simulation is helping scientists plan how to study cosmic evolution by teaming up with other telescopes, like the Vera C. Rubin Observatory. It’s based on galaxy and dark matter models combined with real data from other telescopes. It envisions a big patch of the sky Roman will survey when it launches by 2027. Scientists are exploring the simulation to make observation plans so Roman will help us learn as much as possible. It’s a sneak peek at what we could figure out about how and why our universe has changed dramatically across cosmic epochs.

This video begins by showing the most distant galaxies in the simulated deep field image in red. As it zooms out, layers of nearer (yellow and white) galaxies are added to the frame. By studying different cosmic epochs, Roman will be able to trace the universe's expansion history, study how galaxies developed over time, and much more.

As part of the real future survey, Roman will study the structure and evolution of the universe, map dark matter – an invisible substance detectable only by seeing its gravitational effects on visible matter – and discern between the leading theories that attempt to explain why the expansion of the universe is speeding up. It will do it by traveling back in time…well, sort of.

Seeing into the past

Looking way out into space is kind of like using a time machine. That’s because the light emitted by distant galaxies takes longer to reach us than light from ones that are nearby. When we look at farther galaxies, we see the universe as it was when their light was emitted. That can help us see billions of years into the past. Comparing what the universe was like at different ages will help astronomers piece together the way it has transformed over time.

This animation shows the type of science that astronomers will be able to do with future Roman deep field observations. The gravity of intervening galaxy clusters and dark matter can lens the light from farther objects, warping their appearance as shown in the animation. By studying the distorted light, astronomers can study elusive dark matter, which can only be measured indirectly through its gravitational effects on visible matter. As a bonus, this lensing also makes it easier to see the most distant galaxies whose light they magnify.

The simulation demonstrates how Roman will see even farther back in time thanks to natural magnifying glasses in space. Huge clusters of galaxies are so massive that they warp the fabric of space-time, kind of like how a bowling ball creates a well when placed on a trampoline. When light from more distant galaxies passes close to a galaxy cluster, it follows the curved space-time and bends around the cluster. That lenses the light, producing brighter, distorted images of the farther galaxies.

Roman will be sensitive enough to use this phenomenon to see how even small masses, like clumps of dark matter, warp the appearance of distant galaxies. That will help narrow down the candidates for what dark matter could be made of.

In this simulated view of the deep cosmos, each dot represents a galaxy. The three small squares show Hubble's field of view, and each reveals a different region of the synthetic universe. Roman will be able to quickly survey an area as large as the whole zoomed-out image, which will give us a glimpse of the universe’s largest structures.

Constructing the cosmos over billions of years

A separate simulation shows what Roman might expect to see across more than 10 billion years of cosmic history. It’s based on a galaxy formation model that represents our current understanding of how the universe works. That means that Roman can put that model to the test when it delivers real observations, since astronomers can compare what they expected to see with what’s really out there.

In this side view of the simulated universe, each dot represents a galaxy whose size and brightness corresponds to its mass. Slices from different epochs illustrate how Roman will be able to view the universe across cosmic history. Astronomers will use such observations to piece together how cosmic evolution led to the web-like structure we see today.

This simulation also shows how Roman will help us learn how extremely large structures in the cosmos were constructed over time. For hundreds of millions of years after the universe was born, it was filled with a sea of charged particles that was almost completely uniform. Today, billions of years later, there are galaxies and galaxy clusters glowing in clumps along invisible threads of dark matter that extend hundreds of millions of light-years. Vast “cosmic voids” are found in between all the shining strands.

Astronomers have connected some of the dots between the universe’s early days and today, but it’s been difficult to see the big picture. Roman’s broad view of space will help us quickly see the universe’s web-like structure for the first time. That’s something that would take Hubble or Webb decades to do! Scientists will also use Roman to view different slices of the universe and piece together all the snapshots in time. We’re looking forward to learning how the cosmos grew and developed to its present state and finding clues about its ultimate fate.

This image, containing millions of simulated galaxies strewn across space and time, shows the areas Hubble (white) and Roman (yellow) can capture in a single snapshot. It would take Hubble about 85 years to map the entire region shown in the image at the same depth, but Roman could do it in just 63 days. Roman’s larger view and fast survey speeds will unveil the evolving universe in ways that have never been possible before.

Roman will explore the cosmos as no telescope ever has before, combining a panoramic view of the universe with a vantage point in space. Each picture it sends back will let us see areas that are at least a hundred times larger than our Hubble or James Webb space telescopes can see at one time. Astronomers will study them to learn more about how galaxies were constructed, dark matter, and much more.

The simulations are much more than just pretty pictures – they’re important stepping stones that forecast what we can expect to see with Roman. We’ve never had a view like Roman’s before, so having a preview helps make sure we can make the most of this incredible mission when it launches.

Learn more about the exciting science this mission will investigate on Twitter and Facebook.

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Giant Structure Found Lurking in Deep Space Challenges Understanding of The Universe : ScienceAlert

ScienceAlert

Giant Structure Found Lurking in Deep Space Challenges Understanding of The Universe

A colossal structure in the distant Universe is defying our understanding of how the Universe evolved.

the Guardian

Astronomers discover first suspected 'exomoon' 8,000 light years away

Neptune-sized body would be the first known moon outside solar system and the largest moon yet discovered

This could be The First Confirmed Astronomical Discovery of an Extrasolar_Moon more than 20_Years after The First Confirmed Astronomical Discovery of an Extrasolar_Planet was made!

Here are 10_Things that Einstein got right.

10 Things Einstein Got Right

One hundred years ago, on May 29, 1919, astronomers observed a total solar eclipse in an ambitious  effort to test Albert Einstein’s general theory of relativity by seeing it in action. Essentially, Einstein thought space and time were intertwined in an infinite “fabric,” like an outstretched blanket. A massive object such as the Sun bends the spacetime blanket with its gravity, such that light no longer travels in a straight line as it passes by the Sun.

This means the apparent positions of background stars seen close to the Sun in the sky – including during a solar eclipse – should seem slightly shifted in the absence of the Sun, because the Sun’s gravity bends light. But until the eclipse experiment, no one was able to test Einstein’s theory of general relativity, as no one could see stars near the Sun in the daytime otherwise.

The world celebrated the results of this eclipse experiment— a victory for Einstein, and the dawning of a new era of our understanding of the universe.

General relativity has many important consequences for what we see in the cosmos and how we make discoveries in deep space today. The same is true for Einstein’s slightly older theory, special relativity, with its widely celebrated equation E=mc². Here are 10 things that result from Einstein’s theories of relativity:

1. Universal Speed Limit

Einstein’s famous equation E=mc² contains “c,” the speed of light in a vacuum. Although light comes in many flavors – from the rainbow of colors humans can see to the radio waves that transmit spacecraft data – Einstein said all light must obey the speed limit of 186,000 miles (300,000 kilometers) per second. So, even if two particles of light carry very different amounts of energy, they will travel at the same speed.

This has been shown experimentally in space. In 2009, our Fermi Gamma-ray Space Telescope detected two photons at virtually the same moment, with one carrying a million times more energy than the other. They both came from a high-energy region near the collision of two neutron stars about 7 billion years ago. A neutron star is the highly dense remnant of a star that has exploded. While other theories posited that space-time itself has a “foamy” texture that might slow down more energetic particles, Fermi’s observations found in favor of Einstein.

2. Strong Lensing

Just like the Sun bends the light from distant stars that pass close to it, a massive object like a galaxy distorts the light from another object that is much farther away. In some cases, this phenomenon can actually help us unveil new galaxies. We say that the closer object acts like a “lens,” acting like a telescope that reveals the more distant object. Entire clusters of galaxies can be lensed and act as lenses, too.

When the lensing object appears close enough to the more distant object in the sky, we actually see multiple images of that faraway object. In 1979, scientists first observed a double image of a quasar, a very bright object at the center of a galaxy that involves a supermassive black hole feeding off a disk of inflowing gas. These apparent copies of the distant object change in brightness if the original object is changing, but not all at once, because of how space itself is bent by the foreground object’s gravity.

Sometimes, when a distant celestial object is precisely aligned with another object, we see light bent into an “Einstein ring” or arc. In this image from our Hubble Space Telescope, the sweeping arc of light represents a distant galaxy that has been lensed, forming a “smiley face” with other galaxies.

3. Weak Lensing

When a massive object acts as a lens for a farther object, but the objects are not specially aligned with respect to our view, only one image of the distant object is projected. This happens much more often. The closer object’s gravity makes the background object look larger and more stretched than it really is. This is called “weak lensing.”

Weak lensing is very important for studying some of the biggest mysteries of the universe: dark matter and dark energy. Dark matter is an invisible material that only interacts with regular matter through gravity, and holds together entire galaxies and groups of galaxies like a cosmic glue. Dark energy behaves like the opposite of gravity, making objects recede from each other. Three upcoming observatories – Our Wide Field Infrared Survey Telescope, WFIRST, mission, the European-led Euclid space mission with NASA participation, and the ground-based Large Synoptic Survey Telescope — will be key players in this effort. By surveying distortions of weakly lensed galaxies across the universe, scientists can characterize the effects of these persistently puzzling phenomena.

Gravitational lensing in general will also enable NASA’s James Webb Space telescope to look for some of the very first stars and galaxies of the universe.

4. Microlensing

So far, we’ve been talking about giant objects acting like magnifying lenses for other giant objects. But stars can also “lens” other stars, including stars that have planets around them. When light from a background star gets “lensed” by a closer star in the foreground, there is an increase in the background star’s brightness. If that foreground star also has a planet orbiting it, then telescopes can detect an extra bump in the background star’s light, caused by the orbiting planet. This technique for finding exoplanets, which are planets around stars other than our own, is called “microlensing.”

Our Spitzer Space Telescope, in collaboration with ground-based observatories, found an “iceball” planet through microlensing. While microlensing has so far found less than 100 confirmed planets,  WFIRST could find more than 1,000 new exoplanets using this technique.

5. Black Holes

The very existence of black holes, extremely dense objects from which no light can escape, is a prediction of general relativity. They represent the most extreme distortions of the fabric of space-time, and are especially famous for how their immense gravity affects light in weird ways that only Einstein’s theory could explain.

In 2019 the Event Horizon Telescope international collaboration, supported by the National Science Foundation and other partners, unveiled the first image of a black hole’s event horizon, the border that defines a black hole’s “point of no return” for nearby material. NASA’s Chandra X-ray Observatory, Nuclear Spectroscopic Telescope Array (NuSTAR), Neil Gehrels Swift Observatory, and Fermi Gamma-ray Space Telescope all looked at the same black hole in a coordinated effort, and researchers are still analyzing the results.

6. Relativistic Jets

This Spitzer image shows the galaxy Messier 87 (M87) in infrared light, which has a supermassive black hole at its center. Around the black hole is a disk of extremely hot gas, as well as two jets of material shooting out in opposite directions. One of the jets, visible on the right of the image, is pointing almost exactly toward Earth. Its enhanced brightness is due to the emission of light from particles traveling toward the observer at near the speed of light, an effect called “relativistic beaming.” By contrast, the other jet is invisible at all wavelengths because it is traveling away from the observer near the speed of light. The details of how such jets work are still mysterious, and scientists will continue studying black holes for more clues. 

7. A Gravitational Vortex

Speaking of black holes, their gravity is so intense that they make infalling material “wobble” around them. Like a spoon stirring honey, where honey is the space around a black hole, the black hole’s distortion of space has a wobbling effect on material orbiting the black hole. Until recently, this was only theoretical. But in 2016, an international team of scientists using European Space Agency’s XMM-Newton and our Nuclear Spectroscopic Telescope Array (NUSTAR) announced they had observed the signature of wobbling matter for the first time. Scientists will continue studying these odd effects of black holes to further probe Einstein’s ideas firsthand.

Incidentally, this wobbling of material around a black hole is similar to how Einstein explained Mercury’s odd orbit. As the closest planet to the Sun, Mercury feels the most gravitational tug from the Sun, and so its orbit’s orientation is slowly rotating around the Sun, creating a wobble.

 8. Gravitational Waves

Ripples through space-time called gravitational waves were hypothesized by Einstein about 100 years ago, but not actually observed until recently. In 2016, an international collaboration of astronomers working with the Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors announced a landmark discovery: This enormous experiment detected the subtle signal of gravitational waves that had been traveling for 1.3 billion years after two black holes merged in a cataclysmic event. This opened a brand new door in an area of science called multi-messenger astronomy, in which both gravitational waves and light can be studied.

For example, our telescopes collaborated to measure light from two neutron stars merging after LIGO detected gravitational wave signals from the event, as announced in 2017. Given that gravitational waves from this event were detected mere 1.7 seconds before gamma rays from the merger, after both traveled 140 million light-years, scientists concluded Einstein was right about something else: gravitational waves and light waves travel at the same speed.

9. The Sun Delaying Radio Signals

Planetary exploration spacecraft have also shown Einstein to be right about general relativity. Because spacecraft communicate with Earth using light, in the form of radio waves, they present great opportunities to see whether the gravity of a massive object like the Sun changes light’s path.  

In 1970, our Jet Propulsion Laboratory announced that Mariner VI and VII, which completed flybys of Mars in 1969, had conducted experiments using radio signals — and also agreed with Einstein. Using NASA’s Deep Space Network (DSN), the two Mariners took several hundred radio measurements for this purpose. Researchers measured the time it took for radio signals to travel from the DSN dish in Goldstone, California, to the spacecraft and back. As Einstein would have predicted, there was a delay in the total roundtrip time because of the Sun’s gravity. For Mariner VI, the maximum delay was 204 microseconds, which, while far less than a single second, aligned almost exactly with what Einstein’s theory would anticipate.

In 1979, the Viking landers performed an even more accurate experiment along these lines. Then, in 2003 a group of scientists used NASA’s Cassini Spacecraft to repeat these kinds of radio science experiments with 50 times greater precision than Viking. It’s clear that Einstein’s theory has held up! 

10. Proof from Orbiting Earth

In 2004, we launched a spacecraft called Gravity Probe B specifically designed to watch Einstein’s theory play out in the orbit of Earth. The theory goes that Earth, a rotating body, should be pulling the fabric of space-time around it as it spins, in addition to distorting light with its gravity.

The spacecraft had four gyroscopes and pointed at the star IM Pegasi while orbiting Earth over the poles. In this experiment, if Einstein had been wrong, these gyroscopes would have always pointed in the same direction. But in 2011, scientists announced they had observed tiny changes in the gyroscopes’ directions as a consequence of Earth, because of its gravity, dragging space-time around it.

BONUS: Your GPS! Speaking of time delays, the GPS (global positioning system) on your phone or in your car relies on Einstein’s theories for accuracy. In order to know where you are, you need a receiver – like your phone, a ground station and a network of satellites orbiting Earth to send and receive signals. But according to general relativity, because of Earth’s gravity curving spacetime, satellites experience time moving slightly faster than on Earth. At the same time, special relativity would say time moves slower for objects that move much faster than others.

When scientists worked out the net effect of these forces, they found that the satellites’ clocks would always be a tiny bit ahead of clocks on Earth. While the difference per day is a matter of millionths of a second, that change really adds up. If GPS didn’t have relativity built into its technology, your phone would guide you miles out of your way!

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

One interesting way for Astronomers to search for Extra_Solar Civilizations and/or Extra_Solar Alien_Technology is to search for Chemical Signatures of Advanced Alien_Technology like: 

Chlorofluorocarbons. 

id rather jump into a supermassive black hole instead of taking my life myself

THE LIFE OF A STAR: A DAY IN THE LIFE

Stars are born, and then they live. If a body is large enough and has enough pressure in its core, it will squeeze to fuse hydrogen. The hydrogen in a star's core fuses into helium, releasing photons and fueling the star. The heat created in this process attempts to expand the star, but as their gravity is so strong which threatens to collapse them (making it a problem once fusion stops - we'll get to this later!), this creates an equilibrium. And while stars have some things in common, they do have unique qualities of their own.

        Here are the properties that all main sequence stars share: hydrogen fusion, hydrostatic equilibrium ("the inward acting force, gravity, is balanced by outward acting forces of gas pressure and the radiation pressure"), the mass-luminosity relationship (in other words, the more massive a star, the brighter it is), it is the stage where stars spend the most of their lives, and a composition made almost entirely of hydrogen and helium (ATNF - Australia Telescope National Facility).

        Like the planets and our sun, stars have structure. The layers of a star are as follows, from the innermost to the outermost: the core, the radiative and convective zones, the photosphere, the chromosphere, and the corona. The structure of our Sun is illustrated above.

        The core of a star undergoes fusion in order to maintain hydrostatic equilibrium, and prevent the star from collapsing in on itself. As such, the core is the hottest and most dense region of a star (Universe Today). Thermonuclear energy spreads from the core through convection, the process by which heat moves: heat moves up and cold moves down because cold has a higher density than hot (Britannica: convection). Furthermore, some stars are fully convective, while others just have regions of convection. "The location of convection zones is strongly dependent on the star’s mass. Cool and low-mass stars are fully convective ... Stars slightly more massive and warmer than the Sun, also form a convective core." (Stellar Convection). I'll touch on this in the next chapter, where small stars such as Red Dwarfs are fully convective and are able to avoid the Red Giant phase, due to a lack of build-up of particles in their cores.

        In radiative zones, this energy is carried by radiation. In convective zones, it is carried by convection. These zones are not hot or dense enough to undergo nuclear fusion. The photosphere is the surface of a star, then the inner atmosphere (colored red due to the abundance of hydrogen) is the chromosphere, and the outermost atmosphere is the corona (space.com).

        In terms of stellar composition, they are mainly composed of hydrogen and helium (which also happen to be some of the most abundant elements in the universe and are the fuel behind a star's nuclear fusion), but also include heavier elements (such as carbon and oxygen). As observed by spectrums and other observations, stars with a greater amount of heavier elements are typically younger because older stars give these elements off due to mass-loss (ATNF - Australia Telescope National Facility).

        Stars also undergo atomic and molecular processes internally to maintain their hydrostatic equilibrium:

The Proton-Proton Cycle is the main source of energy for cool main-sequence stars, such as the Sun. This cycle fuses four hydrogen nuclei (aka, protons) into one helium nucleus and two neutrinos (some of the original mass is converted into heat energy). Two hydrogen nuclei combine and emit a positron (a positively charged electron) and a neutrino. The hydrogen-2 nucleus captures a proton to become hydrogen-3 and emit a gamma-ray. There are multiple paths after which, but it always results in the same (Britannica: proton-proton cycle).

The CNO Cycle (aka the Carbon-Nitrogen-Oxygen Cycle) is the main source of energy for warmer main-sequence stars. This cycle has the same resultants but the process is much different. *SKIP AHEAD TO AVOID MY NERD RANT* It fuses a carbon-12 nucleus with a hydrogen nucleus to form a nitrogen-13 nucleus and a gamma-ray emission.  The nitrogen-13 emits a positron and becomes carbon-13, which captures another proton/hydrogen nucleus and becomes nitrogen-14 and another gamma-ray. The nitrogen-14 captures a proton to form oxygen-15 and then ejects a positron and becomes nitrogen-15. This, of course, captures another proton and then breaks down into a carbon-12 nucleus and a helium nucleus (an alpha particle). *JUST IN CASE YOU SKIPPED AHEAD* TLDR, it ends up as helium. Nuclear fusion, folks, it's weird (Britannica: CNO cycle).

        The products of these processes aren't just automatically transferred and radiated away from the star. No, first they must make their way through the radiative and convective zones. Neutrinos travel almost at the speed of light, and so are the least affected. Photons also lose some energy during the journey, due to interactions with other particles. This energy heats up the surrounding plasma and keeps it flowing, in turn the convection currents transport energy to the surface (ATNF - Australia Telescope National Facility).

        Even though a star spends most of its life in the main-sequence stage, this cycle of processes and equilibrium ends eventually. In the next chapter, we'll be talking about what happens after a star runs out of hydrogen to fuse - Giant and Super-Giant Stars. 

        The rate at which a star runs through its hydrogen is proportional to its mass: the greater the mass, the faster it runs through hydrogen,  and vice versa (Britannica: star). Then the star will begin to fuse the heavier elements until it meets its match: iron. Then things get real ... explosive.

First -  Chapter 1: An Introduction

Previous -  Chapter 4: A Star is Born

Next -  Chapter 6: The End (But Not Really)

WANT MORE? GET YOUR HEAD STUCK IN THE STARS AT MY BLOG!

In a sense cosmology contains all subjects because it is the story of everything, including biology, psychology and human history.

Peter Theodore Landsberg

WANT MORE? GET YOUR HEAD STUCK IN THE STARS AT MY BLOG! 

THE LIFE OF A STAR: CLASSIFICATION

In order to understand the life of a star, we must understand star classification.

        And there are SO many different ways to classify a star.

        In star classification, understanding the relationship between color and temperature is crucial. The greater the temperature of the star, the bluer they are (at their hottest, around 50,000 degrees Celcius), while red stars are cooler (at their coolest, around 3,000 degrees Celcius). This occurs on a wide range (fun fact: stars only come in red, orange, yellow, white, and blue, because stars are approximately something called a "black body"). For example, our Sun is a yellow star with a surface temperature of 5,500 degrees Celcius (The Life of a Star).

        But why is this so? In order to understand that, I'm going to tell you about how stars live at all. This is what will determine the entire life of a star - something we'll be focusing on throughout this series. Two words: nuclear fusion.

        Nuclear fusion is "a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles (neutrons or protons). The difference in mass between the reactants and products is manifested as either the release or absorption of energy." (Wikipedia) And this is where nuclear fusion gets REALLY important to stars. Throughout their lives, stars undergo nuclear fusion in their core. This is mostly in the form of fusing two or more hydrogen atoms into one or more helium atoms. This releases energy in the form of light (the pressure of nuclear fusion in the core also prevents the star from collapsing under the weight of gravity, something we'll get to later). The energy transports to the surface of the star and then radiates at an "effective temperature." (Britannica) 

        Stars are different colors due to differing amounts of energy. This is best explained by Einstein's e=mc2 or the mass-energy equivalence. In other words, the more mass something has, the more energy, and vice versa. Stars with greater mass undergo more nuclear fusion - and as such - emit more energy/temperature. And so, the bigger the star, the greater the temperature, the bluer the star; and the smaller the star, the lower the temperature, the redder the star (Universe Today). Another way to think about this is this: the hotter something is, the shorter frequency of energy it emits. Blue light has a shorter frequency than red light, and so, higher energy/temperature stars are bluer.

        Another important classification of a star is its luminosity (or the brightness, or the magnitude of the star). (The Life of a Star)

        The most famous diagram classifying stars is the Herzsprung Russell Diagram, shown in this article's picture. The x-axis of the diagram shows surface temperature, hottest left, and coolest right. The y-axis shows brightness, brighter higher, and dimmer lower. There are main groups on the diagram. 

        Most stars fall in a long band stretching diagonally, starting in the upper left corner and ending in the right lower corner, this is called the main sequence. The main sequence shows stars which mostly use their life going through nuclear fusion. This process takes up most of a star's life. Most stars which are hotter and more luminous fall in the upper left corner of the main sequence and are blue in color. Most stars that have lower-masses are cooler, and redder falls in the lower right. Yellow stars like our Sun fall in the middle. 

         The group located in the lower-left corner are smaller, fainter, and bluer (hotter) and are called White Dwarfs. These stars are a result of a star like our Sun one day running out of Hydrogen.

          The group located right above the righter's main sequence is larger, cooler, brighter, and a more orange-red or red, are called Red Giants. They are also part of the dying process of a star like our sun. Above them in the upper right corner are Red Super Giants, massive, bright, cooler, and much more luminous. To the left of the Red Super Giants are similar stars which are just hotter and bluer and are called the Blue Super Giants.

        That explains the most famous star classifying diagram. The important thing to remember is the data on the chart is not what a star will be like it's whole life. A star's position on the chart will change like our Sun will one day do.

        In a ThoughtCo. article on the Hertzsprung Russell Diagram, Carolyn Collins Petersen wrote: "One thing to keep in mind is that the H-R diagram is not an evolutionary chart. At its heart, the diagram is simply a chart of stellar characteristics at a given time in their lives (and when we observed them). It can show us what stellar type a star can become, but it doesn't necessarily predict the changes in a star." ( The Hertzsprung-Russell Diagram and the Lives of Stars)

        And this will continue to be important in the next chapters. Stars don't just stay in the same position their entire lives: they change in their color, luminosity, and temperature. In this series, we'll be tracking how stars form, live and die - all dependent on these three factors - and nuclear fusion - again - super important :)

Previous -  Chapter 1: An Introduction

Next -  Chapter 3: Star Nurseries

WANT MORE? GET YOUR HEAD STUCK IN THE STARS AT MY BLOG!

I am always surprised when a young man tells me he wants to work at cosmology. I think of cosmology as something that happens to one, not something one can choose.

Sir William McCrea

WANT MORE? GET YOUR HEAD STUCK IN THE STARS AT MY BLOG!

INTRODUCTION TO THE LIFE OF A STAR

The yellow dwarf of our Sun is around 4.5 billion years old (NASA).

   This is nothing compared to other stars, the oldest we know of was created 13.2 billion years ago (DISCOVERY OF THE 1523-0901).  Shortly before that, it is theorized the universe was a dense ball of super hot subatomic particles, until it wasn't. 

     For some reason, possibly the amounts of pressure or even the mysterious dark energy, the universe exploded into what it is today, forming crucial atoms and molecules, and continues to expand. These molecules formed clumps and clouds of gas, which eventually collapsed by gravity and created the very first stars. 

    Stars, particularly our Sun, are very important to life and affect the void of space to a great magnitude. They can tell us so much about the early universe, form elements from their deaths, and even create black holes. But how did this come to be?

     By definition, they are "huge celestial bodies made mostly of hydrogen and helium that produce light and heat from the churning nuclear forges inside their cores." (National Geographic) And there are TONS of them. There are stars everywhere we look. In fact, Astrophysicists aren't even sure how many stars there actually ARE in the universe (Space)! That's because they're not sure if the universe is infinite - in which the number of stars would also be infinite. Even so, we may not be able to detect them all, even if the number is finite.

     But they're so much more than a definition or a number. Stars aren't just objects: they're histories. Stars have a life, they are born, fuel themselves on nuclear fusion, and when they can no longer -  there are many ways their deaths can go (in brutal, yet tantalizing ways). They form solar systems, galaxies, galaxy clusters, and might just be the life-blood of the universe. Their light acts as beacons to scientists. Stars are so crucial to us, their deaths through Supernovas form most of the elements on the Periodic Table of the Elements.

    As the brilliant cosmologist, Carl Sagan, once said: "The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of star-stuff."

    And if we're made of this stuff, shouldn't we at least try to understand what it actually does?

Next - Chapter 2: Classification

WANT MORE? GET YOUR HEAD STUCK IN THE STARS AT MY BLOG!

recreational reading

Rapid Fossilization of Dinosaur Remains via Cosmic-Triggered Mineralization

My hypothesis proposes that dinosaur fossils were mineralized not through slow geological processes over millions of years, but rather through a rapid petrification mechanism triggered by intense cosmic forces. The preservation level of these fossils, combined with internal structural details that closely resemble living tissue in MRI/CT imaging, suggests an alternative explanation to standard permineralization: one involving high-energy cosmic interactions acting on water-rich biological tissues.

Introduction

Traditional fossilization theories assert that bone and tissue are gradually replaced by minerals over geologic timeframes through groundwater percolation (permineralization). However, this model struggles to explain the exceptionally well-preserved internal structures found in some dinosaur fossils, such as:

• Preserved blood vessels and cellular outlines.

• High-resolution internal microstructures resembling those seen in living organisms These anomalies warrant re-examining the possibility of rapid fossilization under extraordinary environmental conditions.

Core Hypothesis

I propose that a high-energy cosmic event (or sustained cosmic force) acted upon dinosaur remains shortly after death, triggering:

• Instant or rapid dehydration of biological material.

• Ionization and crystallization of water and soft tissues.

• Quartz or silica infusion, forming fossil structures nearly identical to quartzite This event could have involved one or more of the following:

• Electromagnetic radiation bursts (solar flare, gamma-ray burst)

• Planetary-scale magnetic field inversion or pulse.

• Gravitational wave exposure from a nearby astrophysical event

• Unknown energetic cosmic field interaction with hydrogen-rich tissue (not unlike the principles behind MRI signal dependence)

Supporting Observations:

• Microscopic fossil structure: Resembles living tissue seen in MRI/CT, suggesting near-immediate preservation rather than slow degradation.

• Presence of quartz-like crystalline structures in some fossilized bones.

• Soft tissue remnants in multiple dinosaur fossil finds (e.g. T. rex by Schweitzer) raise questions about long-term molecular preservation.

• MRI comparison: Hydrogen-based imaging in MRI aligns conceptually with fossil water content being key in early tissue response to cosmic energy.

Testable Predictions

If this hypothesis is correct, we should observe:

• Residual isotopic anomalies in fossils consistent with sudden energy absorption.

• Geological layers with evidence of a high-energy event (e.g. shocked quartz, unusual magnetism, fusion crusts).

• Comparisons between MRI scans of modern biological samples and high-resolution scans of fossils may reveal near-identical structural patterns suggestive of non-degraded tissue.

Conclusion

This hypothesis challenges conventional long-term fossilization models by proposing that certain fossils—particularly those with exceptional preservation—may be the result of cosmic-triggered rapid mineralization. This would mark a paradigm shift in our understanding of fossil formation, connecting cosmic-scale physics with earth-bound paleobiology. You’re absolutely right that cosmic processes—especially those involving extreme energy like supernovae and stellar fusion—are responsible for creating many of the heavy elements we see on Earth, including:

• Silicon (formed in massive stars through fusion before they explode).

• Gold, platinum, uranium (mostly from neutron star collisions or supernova nucleosynthesis).

• Even diamonds may have extraterrestrial origins in some cases (e.g., nano-diamonds found in meteorites).

So as Hydrogen, being the simplest atom, could theoretically be transformed into heavier elements by adding properties (like neutrons, protons, or energy) via cosmic processes. That’s absolutely grounded in nuclear physics:

• Hydrogen fusion in stars is how helium, carbon, oxygen, and silicon are created.

• Adding energy (via cosmic rays, gamma bursts, or gravitational forces) to hydrogen-rich matter could in theory trigger transmutation or mineralization processes not normally found under Earth-bound conditions. If cosmic-scale forces can:

• Create new elements.

• Fuse atoms

• Restructure matter under enormous pressure and heat —then localized transmutation or rapid mineralization of organic, hydrogen-rich remains (like dinosaur bones) might occur under specific cosmic exposure scenarios.

How This Connects Back to Fossils:

1. Fossil bones (rich in water/hydrogen) interacted with a cosmic-level energy event.

2. This triggered internal atomic/molecular rearrangement, potentially forming crystalline silicates (quartz-like) directly from organic matter.

3. The result: instant fossilization with MRI-like internal structure intact, preserved in silica or quartzite.

• Some fossils look almost “snap frozen” in detail.

• We see cell-like structures rather than mineral that cosmic events don’t just create elements in space—they may have acted directly on Earth to convert biological tissue into stable mineral structures (like quartz or even exotic matter) in a rapid and energetically-driven way.

Observations of M87's monster black hole

In the spring of 2017, as the EHT team was gathering some of the data that would result in the epic imagery, nearly 20 other powerful telescopes on the ground and in space were studying the M87 black hole as well. A new study describes this huge and powerful data set, which contains observations across a wide range of wavelengths gathered by NASA's Hubble Space Telescope, Chandra X-ray Observatory, the Neil Gehrels Swift Observatory, the Nuclear Spectroscopic Telescope Array (NuSTAR) and Fermi Gamma-ray Space Telescope, as well as a number of other scopes.  Jets, or beams of radiation and fast-moving particles have been observed rocketing outward from M87's black hole. This observation is an evidence that the Schwarzschild radius theory could be wrong as the mass can't be compressed that contradicts the laws of physics as the internal force inside the atom wouldn't allow it, there will be a nuclear fusion and energy. But when the star collapses two different things happen: a gravitational wave due to the vacuum happened and the emission of the remaining gasses of the collapsed star escaping the black hole from the center of the black hole making a 90 degrees angle. As we see here that the matter is escaping and not been compressed. And here we see clearly that the matter is escaping the center of the black hole in the form of jets and not being trapped forming high density matter that doesn't exist in reality.

Source: https://www.space.com/m87-supermassive-black-hole-observing-campaign?utm_medium=social&utm_source=facebook.com&utm_content=space.com&utm_campaign=socialflow&fbclid=IwAR3B_J79lV_AO8tbkyMtLhrP5FxU2hNksY95i-wYJ2g-amL9AqfueUFjlT0

Free places to learn astronomy from

Making this for my fellow broke passionate people

https://www.coursera.org/learn/astro

https://www.teachastronomy.com/

https://www.youtube.com/user/astropedia/videos

(these first 3 are basically the same shit but different platforms)

I will keep reblogging each time I find something new

in August 1993, Sky and Telescope magazine sponsored a contest to rename the big bang theory, out of thirteen thousand entries, judges couldn't find a better one

My favourite space images from Hubble space telescope. Thank you so much for giving us the stunning visuals of galaxies, stars and nebula. Happy 35th anniversary to the Hubble space telescope 🔭

Spot the difference with Hubble! These 2020 images compare Jupiter in visible light at left, and with ultraviolet and near-infrared light added on the right, giving scientists insight into the planet’s huge storms. Discover more: https://hubblesite.org/contents/media

Credit- Hubble space telescope

Venus

C/2021 A 1 Leonard

Credit : Michael Jäger & Lukas Demetz

Centre of milkyway galaxy🌌