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!)
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!)
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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This colorful image, taken by our Hubble Space Telescope between Feb. 12 and Feb. 18, 2018 , celebrated the Earth-orbiting observatory’s 28th anniversary of viewing the heavens, giving us a window seat to the universe’s extraordinary tapestry of stellar birth and destruction.
At the center of the photo, a monster young star 200,000 times brighter than our Sun is blasting powerful ultraviolet radiation and hurricane-like stellar winds, carving out a fantasy landscape of ridges, cavities, and mountains of gas and dust.
This region epitomizes a typical, raucous stellar nursery full of birth and destruction. The clouds may look majestic and peaceful, but they are in a constant state of flux from the star’s torrent of searing radiation and high-speed particles from stellar winds. As the monster star throws off its natal cocoon of material with its powerful energy, it is suppressing star formation around it.
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Thanks for all of the great questions! Follow me at @Astro_Jessica on Twitter and Instagram and follow the Orion space capsule as it prepares to fly to deep space on Twitter and Facebook. Follow NASA on Tumblr for your regular dose of space: http://nasa.tumblr.com
solivanas: I’ve been designing a space habitat for school that rotates to provide gravity for astronauts within it. Any tips?
1. Not all of humanity is bound to the ground
Since 2000, the International Space Station has been continuously occupied by humans. There, crew members live and work while conducting important research that benefits life on Earth and will even help us eventually travel to deep space destinations, like Mars.
2. We’re working to develop quieter supersonic aircraft that would allow you to travel from New York to Los Angeles in 2 hours
We are working hard to make flight greener, safer and quieter – all while developing aircraft that travel faster, and building an aviation system that operates more efficiently. Seventy years after Chuck Yeager broke the sound barrier in the Bell X-1 aircraft, we’re continuing that supersonic X-plane legacy by working to create a quieter supersonic jet with an aim toward passenger flight.
3. The spacecraft, rockets and systems developed to send astronauts to low-Earth orbit as part of our Commercial Crew Program is also helping us get to Mars
Changes to the human body during long-duration spaceflight are significant challenges to solve ahead of a mission to Mars and back. The space station allows us to perform long duration missions without leaving Earth’s orbit.
Although they are orbiting Earth, space station astronauts spend months at a time in near-zero gravity, which allows scientists to study several physiological changes and test potential solutions. The more time they spend in space, the more helpful the station crew members can be to those on Earth assembling the plans to go to Mars.
4. We’re launching a spacecraft in 2018 that will go “touch the Sun”
In the summer of 2018, we’re launching Parker Solar Probe, a spacecraft that will get closer to the Sun than any other in human history. Parker Solar Probe will fly directly through the Sun’s atmosphere, called the corona. Getting better measurements of this region is key to understanding our Sun.
For instance, the Sun releases a constant outflow of solar material, called the solar wind. We think the corona is where this solar wind is accelerated out into the solar system, and Parker Solar Probe’s measurements should help us pinpoint how that happens.
5. You can digitally fly along with spacecraft…that are actually in space…in real-time!
NASA’s Eyes are immersive, 3D simulations of real events, spacecraft locations and trajectories. Through this interactive app, you can experience Earth and our solar system, the universe and the spacecraft exploring them. Want to watch as our Juno spacecraft makes its next orbit around Juno? You can! Or relive all of the Voyager mission highlights in real-time? You can do that too! Download the free app HERE to start exploring.
6. When you feel far away from home, you can think of the New Horizons spacecraft as it heads toward the Kuiper Belt, and the Voyager spacecraft are beyond the influence of our sun…billions of miles away
Our New Horizons spacecraft completed its Pluto flyby in July 2015 and has continued on its way toward the Kuiper Belt. The spacecraft continues to send back important data as it travels toward deeper space at more than 32,000 miles per hour, and is ~3.2 billion miles from Earth.
In addition to New Horizons, our twin Voyager 1 and 2 spacecraft are exploring where nothing from Earth has flown before. Continuing on their more-than-37-year journey since their 1977 launches, they are each much farther away from Earth and the sun than Pluto. In August 2012, Voyager 1 made the historic entry into interstellar space, the region between the stars, filled with material ejected by the death of nearby stars millions of years ago.
7. There are humans brave enough to not only travel in space, but venture outside space station to perform important repairs and updates during spacewalks
Just this month (October 2017) we’ve already had two spacewalks on the International Space Station...with another scheduled on Oct. 20.
Spacewalks are important events where crew members repair, maintain and upgrade parts of the International Space Station. These activities can also be referred to as EVAs – Extravehicular Activities. Not only do spacewalks require an enormous amount of work to prepare for, but they are physically demanding on the astronauts. They are working in the vacuum of space in only their spacewalking suit.
8. Smart people are up all night working in control rooms all over NASA to ensure that data keeps flowing from our satellites and spacecraft
Our satellites and spacecraft help scientists study Earth and space. Missions looking toward Earth provide information about clouds, oceans, land and ice. They also measure gases in the atmosphere, such as ozone and carbon dioxide and the amount of energy that Earth absorbs and emits. And satellites monitor wildfires, volcanoes and their smoke.
9. A lot of NASA-developed tech has been transferred for use to the public
Our Technology Transfer Program highlights technologies that were originally designed for our mission needs, but have since been introduced to the public market. HERE are a few spinoff technologies that you might not know about.
10. We have a spacecraft currently traveling to an asteroid to collect a sample and bring it back to Earth
OSIRIS-REx is our first-ever mission that will travel to an asteroid and bring a sample of it back to Earth. Currently, the spacecraft is on its way to asteroid Bennu where it will survey and map the object before it “high-fives” the asteroid with its robotic arm to collect a sample, which it will send to Earth.
If everything goes according to plan, on Sept. 24, 2023, the capsule containing the asteroid sample will make a soft landing in the Utah desert.
11. There are Earth-sized planets outside our solar system that may be habitable
To date, we have confirmed 3,000+ exoplanets, which are planets outside our solar system that orbit a Sun-like star. Of these 3,000, some are in the habitable zone – where the temperature is just right for liquid water to exist on the surface.
Recently, our Spitzer Space Telescope revealed the first known system of SEVEN Earth-size planets around a single star. Three of these plants are firmly in the habitable zone, and could have liquid water on the surface, which is key to life as we know it.
12. Earth looks like art from space
In 1960, the United States put its first Earth-observing environmental satellite into orbit around the planet. Over the decades, these satellites have provided invaluable information, and the vantage point of space has provided new perspectives on Earth.
The beauty of Earth is clear, and the artistry ranges from the surreal to the sublime.
13. We’re building a telescope that will be able to see the first stars ever formed in the universe
Wouldn’t it be neat to see a period of the universe’s history that we’ve never seen before? That’s exactly what the James Webb Space Telescope (JWST) will be able to do…plus more!
Specifically, Webb will see the first objects that formed as the universe cooled down after the Big Bang. We don’t know exactly when the universe made the first stars and galaxies – or how for that matter. That is what we are building Webb to help answer.
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- Ellen Ochoa is the first Hispanic director of NASA’s Johnson Space Center and the first Hispanic woman to go to space.
Q: You were the first Hispanic woman to go to space, and you’re the first Hispanic director of the Johnson Space Center. What does the achievement of firsts like these mean to you? What kind of responsibility comes with paving the way?
Becoming an astronaut was a personal goal for me, so I was surprised and overwhelmed to receive such warm support from the entire Hispanic community when I was selected for the astronaut corps. I realized, really for the first time, that people who didn’t even know me were wishing for my success — hoping to share in the pride of future accomplishments, but even more important, willing to provide encouragement in the face of disappointments. In the same way, in addition to working hard to do my best at every position I’ve had, it became an important part of my job to provide encouragement to others, particularly women and minorities underrepresented in STEM [Science Technology Engineering and Math] fields. I hope that by sharing my experiences, others will be inspired to set high goals for themselves.
Q: Have you experienced any particular challenges as a female astronaut? How have you stayed motivated in the face of such challenges?
Actually, the women astronauts who came before me performed their jobs so well that it really wasn’t an issue. There was probably more skepticism due to my research background, given that the job is an operational one, and I didn’t have much experience in that environment. The training we’re provided helped prepare me well, as did veterans astronauts who passed on helpful tips.
Q: As a pioneer of spacecraft technology and a champion of outreach, how do you think we can inspire more women to enter STEM fields?
Use every available communications avenue to let women know about the interesting and rewarding careers in the STEM fields. The website Women@NASA profiles many women around the agency, having them describe in their own words what they do and the path that led them to their careers. And since girls start making choices in middle school that can limit their options later on, there’s a section on the website aimed specifically at middle school girls called Aspire to Inspire featuring women at Johnson Space Center. NASA has also made great use of many social media platforms to spread the word on what we are doing in space exploration, both human and robotics. From the first flyby of Pluto to the completion of a one-year mission onboard the International Space Station, this has been an exciting year for NASA.
Who: In this case, it's really a “what.” The Bigelow Expandable Activity Module (BEAM) is an expandable module developed by Bigelow Aerospace using a NASA patent conceptualized in the 1990s. It is made up of layers of fabric that will expand when installed and equalize with the pressure of the International Space Station.
What: Sensors inside BEAM will monitor temperature and radiation changes, as well as its resistance to potential orbital debris impacts. During its time on station, the airlock between BEAM and the rest of the space station will remained closed, and astronauts will enter only to collect data and help the experiment progress. If BEAM is punctured, the habitat is designed to slowly compress to keep the rest of the space station safe.
With the BEAM launch, deployment and time on station, Bigelow will demonstrate a number of expandable habitat capabilities, such as its folding and packing techniques, radiation protection capability and its thermal, structural and mechanical durability.
When: BEAM is set to launch on SpaceX's eighth Dragon resupply mission April 8, and will be docked to the space station for a minimum two-year demonstration period.
Where: The International Space Station’s mechanical arm will transport BEAM from the spacecraft to a berthing port on the Tranquility module where it will then be expanded.
Why: These expandable modules take up less room on a rocket, but once set up, provide more volume for living and working in space.
When we’re traveling to Mars or beyond, astronauts need habitats that are both durable and easy to transport and to set up. That’s where expandable technology comes in. BEAM is one of the first steps to test expandable structures as a viable alternative to traditional space habitats.
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This second, as you’re reading these words, trillions of tiny particles are hurtling toward you! No, you don’t need to brace yourself. They’re passing through you right now. And now. And now. These particles are called neutrinos, and they’re both everywhere in the cosmos and also extremely hard to find.
Neutrinos are fundamental particles, like electrons, so they can’t be broken down into smaller parts. They also outnumber all the atoms in the universe. (Atoms are made up of electrons, protons, and neutrons. Protons and neutrons are made of quarks … which maybe we’ll talk about another time.) The only thing that outnumbers neutrinos are all the light waves left over from the birth of the universe!
Credit: Photo courtesy of the Pauli Archive, CERN
Physicist Wolfgang Pauli proposed the existence of the neutrino, nearly a century ago. Enrico Fermi coined the name, which means “little neutral one” in Italian, because these particles have no electrical charge and nearly no mass.
Despite how many there are, neutrinos are really hard to study. They travel at almost the speed of light and rarely interact with other matter. Out of the universe’s four forces, ghostly neutrinos are only affected by gravity and the weak force. The weak force is about 10,000 times weaker than the electromagnetic force, which affects electrically charged particles. Because neutrinos carry no charge, move almost as fast as light, and don’t interact easily with other matter, they can escape some really bizarre and extreme places where even light might struggle getting out – like dying stars!
Through the weak force, neutrinos interact with other tiny fundamental particles: electrons, muons [mew-ons], and taus [rhymes with “ow”]. (These other particles are also really cool, but for right now, you just need to know that they’re there.) Scientists actually never detect neutrinos directly. Instead they find signals from these other particles. So they named the three types, or flavors, of neutrinos after them.
Neutrinos are made up of each of these three flavors, but cycle between them as they travel. Imagine going to the store to buy rocky road ice cream, which is made of chocolate ice cream, nuts, and marshmallows. When you get home, you find that it’s suddenly mostly marshmallows. Then in your bowl it’s mostly nuts. But when you take a bite, it’s just chocolate! That’s a little bit like what happens to neutrinos as they zoom through the cosmos.
Credit: CERN
On Earth, neutrinos are produced when unstable atoms decay, which happens in the planet’s core and nuclear reactors. (The first-ever neutrino detection happened in a nuclear reactor in 1955!) They’re also created by particle accelerators and high-speed particle collisions in the atmosphere. (Also, interestingly, the potassium in a banana emits neutrinos – but no worries, bananas are perfectly safe to eat!)
Most of the neutrinos around Earth come from the Sun – about 65 billion every second for every square centimeter. These are produced in the Sun’s core where the immense pressure squeezes together hydrogen to produce helium. This process, called nuclear fusion, creates the energy that makes the Sun shine, as well as neutrinos.
The first neutrinos scientists detected from outside the Milky Way were from SN 1987A, a supernova that occurred only 168,000 light-years away in a neighboring galaxy called the Large Magellanic Cloud. (That makes it one of the closest supernovae scientists have observed.) The light from this explosion reached us in 1987, so it was the first supernova modern astronomers were able to study in detail. The neutrinos actually arrived a few hours before the light from the explosion because of the forces we talked about earlier. The particles escape the star’s core before any of the other effects of the collapse ripple to the surface. Then they travel in pretty much a straight line – all because they don’t interact with other matter very much.
Credit: Martin Wolf, IceCube/NSF
How do we detect particles that are so tiny and fast – especially when they rarely interact with other matter? Well, the National Science Foundation decided to bury a bunch of detectors in a cubic kilometer of Antarctic ice to create the IceCube Neutrino Observatory. The neutrinos interact with other particles in the ice through the weak force and turn into muons, electrons, and taus. The new particles gain the neutrinos’ speed and actually travel faster than light in the ice, which produces a particular kind of radiation IceCube can detect. (Although they would still be slower than light in the vacuum of space.)
In 2013, IceCube first detected high-energy neutrinos, which have energies up to 1,000 times greater than those produced by Earth’s most powerful particle collider. But scientists were puzzled about where exactly these particles came from. Then, in 2017, IceCube detected a high-energy neutrino from a monster black hole powering a high-speed particle jet at a galaxy’s center billions of light-years away. It was accompanied by a flash of gamma rays, the highest energy form of light.
But particle jets aren’t the only place we can find these particles. Scientists recently announced that another high-energy neutrino came from a black hole shredding an unlucky star that strayed too close. The event didn’t produce the neutrino when or how scientists expected, though, so they’ve still got a lot to learn about these mysterious particles!
Keep up with other exciting announcements about our universe by following NASA Universe on Twitter and Facebook.
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Through November 3, catch glimpses of a gibbous Venus, a crescent moon and ringed Saturn in the southwest sky just after sunset.
Wake up before sunrise every day this month to see Jupiter just above Spica, the brightest star in the constellation Virgo, shining in the east-southeast sky.
Just before dawn on November 23-24, see the waning crescent moon just above Jupiter.
November is a great time to see the constellation Ceres as it glides past Cetus, the Whale and you will be able to see the dwarf planet move relative to the background stars, but you’ll need a telescope for this one.
This month, just like last month, there will be three meteor showers--the Northern Tuarids, the Leonids and the November Orionids.
Watch the full November “What’s Up" video for more:
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It’s a scientific conundrum with huge implications for our future: How will our planet react to increasing levels of carbon dioxide in the atmosphere?
Carbon – an essential building block for life – does not stay in one place or take only one form. Carbon, both from natural and human-caused sources, moves within and among the atmosphere, ocean and land.
We’ve been a trailblazer in using space-based and airborne sensors to observe and quantify carbon in the atmosphere and throughout the land and ocean, working with many U.S. and international partners.
Our Orbiting Carbon Observatory-2 (OCO-2) is making unprecedented, accurate global measurements of carbon dioxide levels in the atmosphere and providing unique information on associated natural processes.
ABoVE, our multi-year field campaign in Alaska and Canada is investigating how changes in Arctic ecosystems such as boreal forests in a warming climate result in changes to the balance of carbon moving between the atmosphere and land.
This August we’re embarking on an ocean expedition with the National Science Foundation to the northeast Pacific called EXPORTS that will help scientists develop the capability to better predict how carbon in the ocean moves, which could change as Earth’s climate changes.
ECOSTRESS is slated to launch this summer to the International Space Station to make the first-ever measurements of plant water use and vegetation stress on land – providing key insights into how plants link Earth’s global carbon cycle with its water cycle.
Later this year, ECOSTRESS will be joined on the space station by GEDI, which will use a space borne laser to help estimate how much carbon is locked in forests and how that quantity changes over time.
In early 2019, the OCO-3 instrument is scheduled to launch to the space station to complement OCO-2 observations and allow scientists to probe the daily cycle of carbon dioxide exchange processes over much of the Earth.
And still in the early stages of development is the Geostationary Carbon Cycle Observatory (GeoCarb) satellite, planned to launch in the early 2020s. GeoCarb will collect 10 million observations a day of carbon dioxide, methane and carbon monoxide.
Our emphasis on carbon cycle science and the development of new carbon-monitoring tools is expected to remain a top priority for years to come. READ MORE.
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A cluster of newborn stars herald their birth in this interstellar picture obtained with our Spitzer Space Telescope. These bright young stars are found in a rosebud-shaped (and rose-colored) nebulosity. The star cluster and its associated nebula are located at a distance of 3300 light-years in the constellation Cepheus.
A recent census of the cluster reveals the presence of 130 young stars. The stars formed from a massive cloud of gas and dust that contains enough raw materials to create a thousand Sun-like stars. In a process that astronomers still poorly understand, fragments of this molecular cloud became so cold and dense that they collapsed into stars. Most stars in our Milky Way galaxy are thought to form in such clusters.
The Spitzer Space Telescope image was obtained with an infrared array camera that is sensitive to invisible infrared light at wavelengths that are about ten times longer than visible light. In this four-color composite, emission at 3.6 microns is depicted in blue, 4.5 microns in green, 5.8 microns in orange, and 8.0 microns in red. The image covers a region that is about one quarter the size of the full moon.
As in any nursery, mayhem reigns. Within the astronomically brief period of a million years, the stars have managed to blow a large, irregular bubble in the molecular cloud that once enveloped them like a cocoon. The rosy pink hue is produced by glowing dust grains on the surface of the bubble being heated by the intense light from the embedded young stars. Upon absorbing ultraviolet and visible-light photons produced by the stars, the surrounding dust grains are heated and re-emit the energy at the longer infrared wavelengths observed by Spitzer. The reddish colors trace the distribution of molecular material thought to be rich in hydrocarbons.
The cold molecular cloud outside the bubble is mostly invisible in these images. However, three very young stars near the center of the image are sending jets of supersonic gas into the cloud. The impact of these jets heats molecules of carbon monoxide in the cloud, producing the intricate green nebulosity that forms the stem of the rosebud.
Not all stars are formed in clusters. Away from the main nebula and its young cluster are two smaller nebulae, to the left and bottom of the central 'rosebud,'each containing a stellar nursery with only a few young stars.
Astronomers believe that our own Sun may have formed billions of years ago in a cluster similar to this one. Once the radiation from new cluster stars destroys the surrounding placental material, the stars begin to slowly drift apart.
Additional information about the Spitzer Space Telescope is available at http://www.spitzer.caltech.edu.
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