Who among us doesn’t covertly read tabloid headlines when we pass them by? But if you’re really looking for a dramatic story, you might want to redirect your attention from Hollywood’s stars to the real thing. From birth to death, these burning spheres of gas experience some of the most extreme conditions our cosmos has to offer.
All stars are born in clouds of dust and gas like the Pillars of Creation in the Eagle Nebula pictured below. In these stellar nurseries, clumps of gas form, pulling in more and more mass as time passes. As they grow, these clumps start to spin and heat up. Once they get heavy and hot enough (like, 27 million degrees Fahrenheit or 15 million degrees Celsius), nuclear fusion starts in their cores. This process occurs when protons, the nuclei of hydrogen atoms, squish together to form helium nuclei. This releases a lot of energy, which heats the star and pushes against the force of its gravity. A star is born.
Credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA)
From then on, stars’ life cycles depend on how much mass they have. Scientists typically divide them into two broad categories: low-mass and high-mass stars. (Technically, there’s an intermediate-mass category, but we’ll stick with these two to keep it straightforward!)
Low-mass stars
A low-mass star has a mass eight times the Sun’s or less and can burn steadily for billions of years. As it reaches the end of its life, its core runs out of hydrogen to convert into helium. Because the energy produced by fusion is the only force fighting gravity’s tendency to pull matter together, the core starts to collapse. But squeezing the core also increases its temperature and pressure, so much so that its helium starts to fuse into carbon, which also releases energy. The core rebounds a little, but the star’s atmosphere expands a lot, eventually turning into a red giant star and destroying any nearby planets. (Don’t worry, though, this is several billion years away for our Sun!)
Red giants become unstable and begin pulsating, periodically inflating and ejecting some of their atmospheres. Eventually, all of the star’s outer layers blow away, creating an expanding cloud of dust and gas misleadingly called a planetary nebula. (There are no planets involved.)
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
All that’s left of the star is its core, now called a white dwarf, a roughly Earth-sized stellar cinder that gradually cools over billions of years. If you could scoop up a teaspoon of its material, it would weigh more than a pickup truck. (Scientists recently found a potential planet closely orbiting a white dwarf. It somehow managed to survive the star’s chaotic, destructive history!)
High-mass stars
A high-mass star has a mass eight times the Sun’s or more and may only live for millions of years. (Rigel, a blue supergiant in the constellation Orion, pictured below, is 18 times the Sun’s mass.)
Credit: Rogelio Bernal Andreo
A high-mass star starts out doing the same things as a low-mass star, but it doesn’t stop at fusing helium into carbon. When the core runs out of helium, it shrinks, heats up, and starts converting its carbon into neon, which releases energy. Later, the core fuses the neon it produced into oxygen. Then, as the neon runs out, the core converts oxygen into silicon. Finally, this silicon fuses into iron. These processes produce energy that keeps the core from collapsing, but each new fuel buys it less and less time. By the point silicon fuses into iron, the star runs out of fuel in a matter of days. The next step would be fusing iron into some heavier element, but doing requires energy instead of releasing it.
The star’s iron core collapses until forces between the nuclei push the brakes, and then it rebounds back to its original size. This change creates a shock wave that travels through the star’s outer layers. The result is a huge explosion called a supernova.
What’s left behind depends on the star’s initial mass. Remember, a high-mass star is anything with a mass more than eight times the Sun’s — which is a huge range! A star on the lower end of this spectrum leaves behind a city-size, superdense neutron star. (Some of these weird objects can spin faster than blender blades and have powerful magnetic fields. A teaspoon of their material would weigh as much as a mountain.)
At even higher masses, the star’s core turns into a black hole, one of the most bizarre cosmic objects out there. Black holes have such strong gravity that light can’t escape them. If you tried to get a teaspoon of material to weigh, you wouldn’t get it back once it crossed the event horizon — unless it could travel faster than the speed of light, and we don’t know of anything that can! (We’re a long way from visiting a black hole, but if you ever find yourself near one, there are some important safety considerations you should keep in mind.)
The explosion also leaves behind a cloud of debris called a supernova remnant. These and planetary nebulae from low-mass stars are the sources of many of the elements we find on Earth. Their dust and gas will one day become a part of other stars, starting the whole process over again.
That’s a very brief summary of the lives, times, and deaths of stars. (Remember, there’s that whole intermediate-mass category we glossed over!) To keep up with the most recent stellar news, follow NASA Universe on Twitter and Facebook.
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Our Sun has an entourage of planets, moons, and smaller objects to keep it company as it traverses the galaxy. But it’s still lonely compared to many of the other stars out there, which often come in pairs. These cosmic couples, called binary stars, are very important in astronomy because they can easily reveal things that are much harder to learn from stars that are on their own. And some of them could even host habitable planets!
The birth of a stellar duo
New stars emerge from swirling clouds of gas and dust that are peppered throughout the galaxy. Scientists still aren’t sure about all the details, but turbulence deep within these clouds may give rise to knots that are denser than their surroundings. The knots have stronger gravity, so they can pull in more material and the cloud may begin to collapse.
The material at the center heats up. Known as a protostar, it is this hot core that will one day become a star. Sometimes these spinning clouds of collapsing gas and dust may break up into two, three, or even more blobs that eventually become stars. That would explain why the majority of the stars in the Milky Way are born with at least one sibling.
Seeing stars
We can’t always tell if we’re looking at binary stars using just our eyes. They’re often so close together in the sky that we see them as a single star. For example, Sirius, the brightest star we can see at night, is actually a binary system (see if you can spot both stars in the photo above). But no one knew that until the 1800s.
Precise observations showed that Sirius was swaying back and forth like it was at a middle school dance. In 1862, astronomer Alvan Graham Clark used a telescope to see that Sirius is actually two stars that orbit each other.
But even through our most powerful telescopes, some binary systems still masquerade as a single star. Fortunately there are a couple of tricks we can use to spot these pairs too.
Since binary stars orbit each other, there’s a chance that we’ll see some stars moving toward and away from us as they go around each other. We just need to have an edge-on view of their orbits. Astronomers can detect this movement because it changes the color of the star’s light – a phenomenon known as the Doppler effect.
Stars we can find this way are called spectroscopic binaries because we have to look at their spectra, which are basically charts or graphs that show the intensity of light being emitted over a range of energies. We can spot these star pairs because light travels in waves. When a star moves toward us, the waves of its light arrive closer together, which makes its light bluer. When a star moves away, the waves are lengthened, reddening its light.
Sometimes we can see binary stars when one of the stars moves in front of the other. Astronomers find these systems, called eclipsing binaries, by measuring the amount of light coming from stars over time. We receive less light than usual when the stars pass in front of each other, because the one in front will block some of the farther star’s light.
Sibling rivalry
Twin stars don’t always get along with each other – their relationship may be explosive! Type Ia supernovae happen in some binary systems in which a white dwarf – the small, hot core left over when a Sun-like star runs out of fuel and ejects its outer layers – is stealing material away from its companion star. This results in a runaway reaction that ultimately detonates the thieving star. The same type of explosion may also happen when two white dwarfs spiral toward each other and collide. Yikes!
Scientists know how to determine how bright these explosions should truly be at their peak, making Type Ia supernovae so-called standard candles. That means astronomers can determine how far away they are by seeing how bright they look from Earth. The farther they are, the dimmer they appear. Astronomers can also look at the wavelengths of light coming from the supernovae to find out how fast the dying stars are moving away from us.
Astronomers like finding binary systems because it’s a lot easier to learn more about stars that are in pairs than ones that are on their own. That’s because the stars affect each other in ways we can measure. For example, by paying attention to how the stars orbit each other, we can determine how massive they are. Since heavier stars burn hotter and use up their fuel more quickly than lighter ones, knowing a star’s mass reveals other interesting things too.
By studying how the light changes in eclipsing binaries when the stars cross in front of each other, we can learn even more! We can figure out their sizes, masses, how fast they’re each spinning, how hot they are, and even how far away they are. All of that helps us understand more about the universe.
Tatooine worlds
Thanks to observatories such as our Kepler Space Telescope, we know that worlds like Luke Skywalker’s home planet Tatooine in “Star Wars” exist in real life. And if a planet orbits at the right distance from the two stars, it could even be habitable (and stay that way for a long time).
In 2019, our Transiting Exoplanet Survey Satellite (TESS) found a planet, known as TOI-1338 b, orbiting a pair of stars. These worlds are tricker to find than planets with only one host star, but TESS is expected to find several more!
How will the James Webb Space Telescope change how we see the universe? Ask an expert!
The James Webb Space Telescope is launching on December 22, 2021. Webb’s revolutionary technology will explore every phase of cosmic history—from within our solar system to the most distant observable galaxies in the early universe, to everything in between. Postdoctoral Research Associate Naomi Rowe-Gurney will be taking your questions about Webb and Webb science in an Answer Time session on Tuesday, December 14 from noon to 1 p.m EST here on our Tumblr!
Dr. Naomi Rowe-Gurney recently completed her PhD at the University of Leicester and is now working at NASA Goddard Space Flight Center as a postdoc through Howard University. As a planetary scientist for the James Webb Space Telescope, she’s an expert on the atmospheres of the ice giants in our solar system — Uranus and Neptune — and how the Webb telescope will be able to learn more about them.
The James Webb Space Telescope – fun facts:
Webb is so big it has to fold origami-style to fit into its rocket and will unfold like a “Transformer” in space.
Webb is about 100 times more powerful than the Hubble Space Telescope and designed to see the infrared, a region Hubble can only peek at.
With unprecedented sensitivity, it will peer back in time over 13.5 billion years to see the first galaxies born after the Big Bang––a part of space we’ve never seen.
It will study galaxies near and far, young and old, to understand how they evolve.
Webb will explore distant worlds and study the atmospheres of planets orbiting other stars, known as exoplanets, searching for chemical fingerprints of possible habitability.
Science is a shared endeavor. We learn more when we work together. Today, July 18, we’re using three different space telescopes to observe the same star/planet system!
As our Transiting Exoplanet Survey Satellite (TESS) enters its third year of observations, it’s taking a new look at a familiar system this month. And today it won’t be alone. Astronomers are looking at AU Microscopii, a young fiery nearby star – about 22 million years old – with the TESS, NICER and Swift observatories.
TESS will be looking for more transits – the passage of a planet across a star – of a recently-discovered exoplanet lurking in the dust of AU Microscopii (called AU Mic for short). Astronomers think there may be other worlds in this active system, as well!
Our Neutron star Interior Composition Explorer (NICER) telescope on the International Space Station will also focus on AU Mic today. While NICER is designed to study neutron stars, the collapsed remains of massive stars that exploded as supernovae, it can study other X-ray sources, too. Scientists hope to observe stellar flares by looking at the star with its high-precision X-ray instrument.
Scientists aren’t sure where the X-rays are coming from on AU Mic — it could be from a stellar corona or magnetic hot spots. If it’s from hot spots, NICER might not see the planet transit, unless it happens to pass over one of those spots, then it could see a big dip!
A different team of astronomers will use our Neil Gehrels Swift Observatory to peer at AU Mic in X-ray and UV to monitor for high-energy flares while TESS simultaneously observes the transiting planet in the visible spectrum. Stellar flares like those of AU Mic can bathe planets in radiation.
Studying high-energy flares from AU Mic with Swift will help us understand the flare-rate over time, which will help with models of the planet’s atmosphere and the system’s space weather. There’s even a (very) small chance for Swift to see a hint of the planet’s transit!
The flares that a star produces can have a direct impact on orbiting planets’ atmospheres. The high-energy photons and particles associated with flares can alter the chemical makeup of a planet’s atmosphere and erode it away over time.
Another time TESS teamed up with a different spacecraft, it discovered a hidden exoplanet, a planet beyond our solar system called AU Mic b, with the now-retired Spitzer Space Telescope. That notable discovery inspired our latest poster! It’s free to download in English and Spanish.
Spitzer’s infrared instrument was ideal for peering at dusty systems! Astronomers are still using data from Spitzer to make discoveries. In fact, the James Webb Space Telescope will carry on similar study and observe AU Mic after it launches next year.
Simulating alien worlds, designing spacecraft with origami and using tiny fossils to understand the lives of ancient organisms are all in a day’s work for interns at NASA.
Here’s how interns are taking our missions and science farther.
1. Connecting Satellites in Space
Becca Foust looks as if she’s literally in space – or, at least, on a sci-fi movie set. She’s surrounded by black, except for the brilliant white comet model suspended behind her. Beneath the socks she donned just for this purpose, the black floor reflects the scene like perfectly still water across a lake as she describes what happens here: “We have five spacecraft simulators that ‘fly’ in a specially designed flat-floor facility,” she says. “The spacecraft simulators use air bearings to lift the robots off the floor, kind of like a reverse air hockey table. The top part of the spacecraft simulators can move up and down and rotate all around in a similar way to real satellites.” It’s here, in this test bed on the Caltech campus, that Foust is testing an algorithm she’s developing to autonomously assemble and disassemble satellites in space. “I like to call it space K’nex, like the toys. We’re using a bunch of component satellites and trying to figure out how to bring all of the pieces together and make them fit together in orbit,” she says. A NASA Space Technology Research Fellow, who splits her time between Caltech and NASA’s Jet Propulsion Laboratory (JPL), working with Soon-Jo Chung and Fred Hadaegh, respectively, Foust is currently earning her Ph.D. at the University of Illinois at Urbana-Champaign. She says of her fellowship, “I hope my research leads to smarter, more efficient satellite systems for in-space construction and assembly.”
2. Diving Deep on the Science of Alien Oceans
Three years ago, math and science were just subjects Kathy Vega taught her students as part of Teach for America. Vega, whose family emigrated from El Salvador, was the first in her family to go to college. She had always been interested in space and even dreamed about being an astronaut one day, but earned a degree in political science so she could get involved in issues affecting her community. But between teaching and encouraging her family to go into science, It was only a matter of time before she realized just how much she wanted to be in the STEM world herself. Now an intern at NASA JPL and in the middle of earning a second degree, this time in engineering physics, Vega is working on an experiment that will help scientists search for life beyond Earth.
“My project is setting up an experiment to simulate possible ocean compositions that would exist on other worlds,” says Vega. Jupiter’s moon Europa and Saturn’s moon Enceladus, for example, are key targets in the search for life beyond Earth because they show evidence of global oceans and geologic activity. Those factors could allow life to thrive. JPL is already building a spacecraft designed to orbit Europa and planning for another to land on the icy moon’s surface. “Eventually, [this experiment] will help us prepare for the development of landers to go to Europa, Enceladus and another one of Saturn’s moons, Titan, to collect seismic measurements that we can compare to our simulated ones,” says Vega. “I feel as though I’m laying the foundation for these missions.”
3. Unfolding Views on Planets Beyond Our Solar System
“Origami is going to space now? This is amazing!” Chris Esquer-Rosas had been folding – and unfolding – origami since the fourth grade, carefully measuring the intricate patterns and angles produced by the folds and then creating new forms from what he’d learned. “Origami involves a lot of math. A lot of people don’t realize that. But what actually goes into it is lots of geometric shapes and angles that you have to account for,” says Esquer-Rosas. Until three years ago, the computer engineering student at San Bernardino College had no idea that his origami hobby would turn into an internship opportunity at NASA JPL. That is, until his long-time friend, fellow origami artist and JPL intern Robert Salazar connected him with the Starshade project. Starshade has been proposed as a way to suppress starlight that would otherwise drown out the light from planets outside our solar system so we can characterize them and even find out if they’re likely to support life. Making that happen requires some heavy origami – unfurling a precisely-designed, sunflower-shaped structure the size of a baseball diamond from a package about half the size of a pitcher’s mound. It’s Esquer-Rosas’ project this summer to make sure Starshade’s “petals” unfurl without a hitch. Says Esquer-Rosas, “[The interns] are on the front lines of testing out the hardware and making sure everything works. I feel as though we’re contributing a lot to how this thing is eventually going to deploy in space.”
4. Making Leaps in Extreme Robotics
Wheeled rovers may be the norm on Mars, but Sawyer Elliott thinks a different kind of rolling robot could be the Red Planet explorer of the future. This is Elliott’s second year as a fellow at NASA JPL, researching the use of a cube-shaped robot for maneuvering around extreme environments, like rocky slopes on Mars or places with very little gravity, like asteroids. A graduate student in aerospace engineering at Cornell University, Elliott spent his last stint at JPL developing and testing the feasibility of such a rover. “I started off working solely on the rover and looking at can we make this work in a real-world environment with actual gravity,” says Elliott. “It turns out we could.” So this summer, he’s been improving the controls that get it rolling or even hopping on command. In the future, Elliott hopes to keep his research rolling along as a fellow at JPL or another NASA center. “I’m only getting more and more interested as I go, so I guess that’s a good sign,” he says.
5. Starting from the Ground Up
Before the countdown to launch or the assembling of parts or the gathering of mission scientists and engineers, there are people like Joshua Gaston who are helping turn what’s little more than an idea into something more. As an intern with NASA JPL’s project formulation team, Gaston is helping pave the way for a mission concept that aims to send dozens of tiny satellites, called CubeSats, beyond Earth’s gravity to other bodies in the solar system. “This is sort of like step one,” says Gaston. “We have this idea and we need to figure out how to make it happen.” Gaston’s role is to analyze whether various CubeSat models can be outfitted with the needed science instruments and still make weight. Mass is an important consideration in mission planning because it affects everything from the cost to the launch vehicle to the ability to launch at all. Gaston, an aerospace engineering student at Tuskegee University, says of his project, “It seems like a small role, but at the same time, it’s kind of big. If you don’t know where things are going to go on your spacecraft or you don’t know how the spacecraft is going to look, it’s hard to even get the proposal selected.”
6. Finding Life on the Rocks
By putting tiny samples of fossils barely visible to the human eye through a chemical process, a team of NASA JPL scientists is revealing details about organisms that left their mark on Earth billions of years ago. Now, they have set their sights on studying the first samples returned from Mars in the future. But searching for signatures of life in such a rare and limited resource means the team will have to get the most science they can out of the smallest sample possible. That’s where Amanda Allen, an intern working with the team in JPL’s Astrobiogeochemistry, or abcLab, comes in. “Using the current, state-of-the-art method, you need a sample that’s 10 times larger than we’re aiming for,” says Allen, an Earth science undergraduate at the University of California, San Diego, who is doing her fifth internship at JPL. “I’m trying to get a different method to work.” Allen, who was involved in theater and costume design before deciding to pursue Earth science, says her “superpower” has always been her ability to find things. “If there’s something cool to find on Mars related to astrobiology, I think I can help with that,” she says.
7. Taking Space Flight Farther
If everything goes as planned and a thruster like the one Camille V. Yoke is working on eventually helps send astronauts to Mars, she’ll probably be first in line to play the Mark Watney role. “I’m a fan of the Mark Watney style of life [in “The Martian”], where you’re stranded on a planet somewhere and the only thing between you and death is your own ability to work through problems and engineer things on a shoestring,” says Yoke. A physics major at the University of South Carolina, Yoke is interning with a team that’s developing a next-generation electric thruster designed to accelerate spacecraft more efficiently through the solar system. “Today there was a brief period in which I knew something that nobody else on the planet knew – for 20 minutes before I went and told my boss,” says Yoke. “You feel like you’re contributing when you know that you have discovered something new.”
8. Searching for Life Beyond Our Solar System
Without the option to travel thousands or even tens of light-years from Earth in a single lifetime, scientists hoping to discover signs of life on planets outside our solar system, called exoplanets, are instead creating their own right here on Earth. This is Tre’Shunda James’ second summer simulating alien worlds as an intern at NASA JPL. Using an algorithm developed by her mentor, Renyu Hu, James makes small changes to the atmospheric makeup of theoretical worlds and analyzes whether the combination creates a habitable environment. “This model is a theoretical basis that we can apply to many exoplanets that are discovered,” says James, a chemistry and physics major at Occidental College in Los Angeles. “In that way, it’s really pushing the field forward in terms of finding out if life could exist on these planets.” James, who recently became a first-time co-author on a scientific paper about the team’s findings, says she feels as though she’s contributing to furthering the search for life beyond Earth while also bringing diversity to her field. “I feel like just being here, exploring this field, is pushing the boundaries, and I’m excited about that.”
9. Spinning Up a Mars Helicopter
Chloeleen Mena’s role on the Mars Helicopter project may be small, but so is the helicopter designed to make the first flight on the Red Planet. Mena, an electrical engineering student at Embry-Riddle Aeronautical University, started her NASA JPL internship just days after NASA announced that the helicopter, which had been in development at JPL for nearly five years, would be going to the Red Planet aboard the Mars 2020 rover. This summer, Mena is helping test a part needed to deploy the helicopter from the rover once it lands on Mars, as well as writing procedures for future tests. “Even though my tasks are relatively small, it’s part of a bigger whole,” she says.
10. Preparing to See the Unseen on Jupiter’s Moon Europa
In the 2020s, we’re planning to send a spacecraft to the next frontier in the search for life beyond Earth: Jupiter’s moon Europa. Swathed in ice that’s intersected by deep reddish gashes, Europa has unveiled intriguing clues about what might lie beneath its surface – including a global ocean that could be hospitable to life. Knowing for sure hinges on a radar instrument that will fly aboard the Europa Clipper orbiter to peer below the ice with a sort of X-ray vision and scout locations to set down a potential future lander. To make sure everything works as planned, NASA JPL intern Zachary Luppen is creating software to test key components of the radar instrument. “Whatever we need to do to make sure it operates perfectly during the mission,” says Luppen. In addition to helping things run smoothly, the astronomy and physics major says he hopes to play a role in answering one of humanity’s biggest questions. “Contributing to the mission is great in itself,” says Luppen. “But also just trying to make as many people aware as possible that this science is going on, that it’s worth doing and worth finding out, especially if we were to eventually find life on Europa. That changes humanity forever!”
Read the full web version of this week’s ‘Solar System: 10 Things to Know” article HERE.
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If we could zoom waaaay out, we would see that galaxies and galaxy clusters make up large, fuzzy threads, like the strands of a giant cobweb. But we’ll work our way out to that. First let’s start at home and look at our planet’s different cosmic communities.
Our home star system
Earth is one of eight planets — Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune — that orbit the Sun. But our solar system is more than just planets; it also has a lot of smaller objects.
An asteroid belt circles the Sun between Mars and Jupiter. Beyond Neptune is a doughnut-shaped region of icy objects called the Kuiper Belt. This is where dwarf planets like Pluto and Makemake are found and is likely the source of short-period comets (like Haley’s comet), which orbit the Sun in less than 200 years.
Scientists think that even farther out lies the Oort Cloud, also a likely source of comets. This most distant region of our solar system is a giant spherical shell storing additional icy space debris the size of mountains, or larger! The outer edge of the Oort Cloud extends to about 1.5 light-years from the Sun — that’s the distance light travels in a year and a half (over 9 trillion miles).
Let’s zoom out to look at the whole Milky Way galaxy, which contains more than 100 billion stars. Many are found in the galaxy’s disk — the pancake-shaped part of a spiral galaxy where the spiral arms lie. The brightest and most massive stars are found in the spiral arms, close to their birth places. Dimmer, less massive stars can be found sprinkled throughout the disk. Also found throughout the spiral arms are dense clouds of gas and dust called nebulae. The Sun lies in a small spiral arm called the Orion Spur.
Our galaxy also has several orbiting companion galaxies ranging from about 25,000 to 1.4 million light-years away. The best known of these are the Large and Small Magellanic Clouds, which are visible to the unaided eye from Earth’s Southern Hemisphere.
Our galactic neighborhood
The Milky Way and Andromeda, our nearest neighboring spiral galaxy, are just two members of a small group of galaxies called the Local Group. They and the other members of the group, 50 to 80 smaller galaxies, spread across about 10 million light-years.
The Local Group lies at the outskirts of an even larger structure. It is just one of at least 100 groups and clusters of galaxies that make up the Virgo Supercluster. This cluster of clusters spans about 110 million light-years!
Galaxies aren’t the only thing found in a galaxy cluster, though. We also find hot gas, as shown above in the bright X-ray light (in pink) that surrounds the galaxies (in optical light) of cluster Abell 1413, which is a picturesque member of a different supercluster. Plus, there is dark matter throughout the cluster that is only detectable through its gravitational interactions with other objects.
The Cosmic Web
The Virgo Supercluster is just one of many, many other groups of galaxies. But the universe’s structure is more than just galaxies, clusters, and the stuff contained within them.
For more than two decades, astronomers have been mapping out the locations of galaxies, revealing a filamentary, web-like structure. This large-scale backbone of the cosmos consists of dark matter laced with gas. Galaxies and clusters form along this structure, and there are large voids in between.
The scientific visualizations of this “cosmic web” look a little like a spider web, but that would be one colossal spider! <shudder>
And there you have the different communities that define Earth’s place in the universe. Our tiny planet is a small speck on a crumb of that giant cosmic web!
It’s easy to get lost in fantasy worlds through science-fiction movies and novels, but did you know that some of your favorite fairy tale characters actually exist in cosmic form? From dwarfs and giants to shape-shifters and buried treasure, the universe is home to a multitude of mystical objects.
White Dwarf Stars
You’ve probably heard of dwarfs like Happy and Sneezy (or Gimli and Thorin), but it’s unlikely you’re familiar with the space-dwelling dwarfs with names like Sirius B and ASASSN-16oh. White dwarf stars like these are typically about the size of Earth, which is pretty small as far as stars go. They represent one of three final stages of stellar evolution, along with neutron stars and black holes. Each star’s mass determines which one it will ultimately become. Stars much more massive than the Sun typically become neutron stars or black holes, and lower-mass stars end up as white dwarfs.
Our Sun will eventually become a white dwarf after it exhausts its fuel, but don’t worry — we’ve got several billion years to go! Before it is reduced to a white dwarf it will actually expand into a red giant, swelling out to encompass Earth’s orbit. But we don’t have to wait billions of years to see stellar giants … some already peek out at us from the cosmic deep.
Giants and Supergiants
The red giant star Aldebaran, located about 65 light-years away, is about 5,000 times bigger than Earth. Our Cassini spacecraft imaged Aldebaran through Saturn’s rings in 2006, but you can see it for yourself during northern winter. Just look for the brightest star in the constellation Taurus.
Fairy tale giants may be taller than trees, but these supergiant stars can be over 100,000 times “taller” than our entire planet! Supergiant stars are likely becoming more rare as time goes on. While scientists believe they used to be more common, our whole galaxy now contains just a small smattering of supergiants.
These massive stars grace the galaxy for a relatively small amount of time. They burn through their fuel extremely quickly — in just a few million years, as opposed to hundreds of billions of years for the smallest stars! Supergiants often end their lives in dramatic explosions called supernovae.
Betelgeuse — the bright, reddish star marking the shoulder of Orion — is nearing the end of its life and has expanded to become a red supergiant star. It is destined to explode as a supernova, which might happen tonight … or within the next few hundred thousand years.
Ghostly Solar Neutrinos
Even an average star like our Sun has some seemingly magical qualities. Each second, it sends billions of phantom-like neutrino particles out into space. They travel almost as fast as light and don’t usually interact with normal matter. Billions of them are zipping harmlessly straight through your body while you read this. Even at night they go through the entire Earth before reaching you!
But that’s not all … these ghostly particles are shape-shifters, too! Neutrinos can change characteristics over time, morphing between different versions of themselves. Spooky!
Buried Treasure in the Heart of the Galaxy
Extensive clouds of dust enshroud the heart of our Milky Way galaxy, hiding it from our view — at least when it comes to visible light. The dust isn’t as big a problem for infrared light, however, which has allowed us to get a glimpse of our galaxy’s chaotic core thanks to our Hubble and Spitzer space telescopes.
Future missions may peer into the galactic core in search of buried treasure — thousands of planets orbiting distant stars!
Want to learn about more cosmic objects? Find them here!
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.
Are we alone? How did we get here? Where are we headed?
At NASA, our mission is to explore. We visit destinations in our solar system and study worlds beyond to better understand these big questions.
We also dream. We dream of traveling to distant worlds, and what that might be like. In the video above you can see fanciful, imagined adventures to real places we’ve studied at NASA.
How We Did It
Check out how we created these otherworldly scenes in the video below. A NASA videographer used green screens to add motion and real people to bring life to our series of solar system and exoplanet travel posters.
Let’s dive into one example from the video. The shot of kayaking on Titan showcases the real rivers and lakes of liquid methane and ethane that slosh and flow on Saturn’s largest moon. Titan’s mysterious surface was revealed by our Cassini spacecraft, which also deployed the European Space Agency’s Huygens probe to the surface. The atmosphere on Titan is so thick, and the gravity so light, that with each strike of a paddle, you might be lofted above the swift current as you ride the tides through a narrow strait called the Throat of Kraken. NASA scientist Mike Malaska studies Titan and collaborated on the poster featured in the video. His research informed the artwork, and so did a hobby: kayaking. Those ultra-cold chemical seas might be even more of a challenge than shown here. Your boat might crack, or even dissolve, Malaska said.
We’ll learn more about Titan when our Dragonfly mission of dual quadcoptors — rotorcraft with eight blades each — visits the icy moon in 2034.
Science Never Stops
Our understanding of other worlds is always evolving, and sometimes we learn new details after we illustrate our science. In one of our travel posters, we show a traveler standing on the surface of exoplanet Kepler-16b with two shadows formed by the planet’s two suns. The planet does indeed orbit two stars, but with later size and mass refinements, we now think it would be hard to stand there and enjoy a binary sunset. There isn’t a solid surface to stand on a gas planet, and that’s what Kepler-16b now appears to be!
In addition to sharing how sublime science can be, these scenes are a reminder that there are lots of careers in the space program, not just scientist, engineer, or astronaut. A creative team at NASA’s Jet Propulsion Laboratory in Southern California produced the travel posters, originally to help share the work of NASA’s Exoplanet Exploration Program. They are the result of lots of brainstorming and discussion with real NASA scientists, engineers, and expert communicators. The video versions of these spacey travel scenes were produced by visualization experts at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
All of this work is meant to inspire, and to explore the edge of possibility. It’s also an invitation. With science, we’re stepping into the future. Join us?
LaRue Burbank, mathematician and computer, is just one of the many women who were instrumental to NASA missions.
4 Little Known Women Who Made Huge Contributions to NASA
Women have always played a significant role at NASA and its predecessor NACA, although for much of the agency’s history, they received neither the praise nor recognition that their contributions deserved. To celebrate Women’s History Month – and properly highlight some of the little-known women-led accomplishments of NASA’s early history – our archivists gathered the stories of four women whose work was critical to NASA’s success and paved the way for future generations.