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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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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!
Learn more about the exciting science Roman will investigate on X and Facebook.
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Our Nancy Grace Roman Space Telescope recently passed a major review of the ground system, which will make data from the spacecraft available to scientists and the public.
Since the telescope has a gigantic field of view, it will be able to send us tons of data really quickly — about 500 times faster than our Hubble Space Telescope! That means Roman will send back a flood of new information about the cosmos.
Let’s put it into perspective — if we printed out all of Roman’s data as text, the paper would have to hurtle out of the printer at 40,000 miles per hour (64,000 kilometers per hour) to keep up! At that rate, the stack of papers would tower 330 miles (530 kilometers) high after a single day. By the end of Roman’s five-year primary mission, the stack would extend even farther than the Moon! With all this data, Roman will bring all kinds of cosmic treasures to light, from dark matter and dark energy to distant planets and more!
Learn more about the Roman Space Telescope.
Make sure to follow us on Tumblr for your regular dose of space!
Our Nancy Grace Roman Space Telescope recently passed a major review of the ground system, which will make data from the spacecraft available to scientists and the public.
Since the telescope has a gigantic field of view, it will be able to send us tons of data really quickly — about 500 times faster than our Hubble Space Telescope! That means Roman will send back a flood of new information about the cosmos.
Let’s put it into perspective — if we printed out all of Roman’s data as text, the paper would have to hurtle out of the printer at 40,000 miles per hour (64,000 kilometers per hour) to keep up! At that rate, the stack of papers would tower 330 miles (530 kilometers) high after a single day. By the end of Roman’s five-year primary mission, the stack would extend even farther than the Moon! With all this data, Roman will bring all kinds of cosmic treasures to light, from dark matter and dark energy to distant planets and more!
Learn more about the Roman Space Telescope.
Make sure to follow us on Tumblr for your regular dose of space!