Nicknamed “Earendel” (“morning star” in Old English), this star existed within the first billion years after the universe’s birth in the big bang. Earendel is so far away from Earth that its light has taken 12.9 billion years to reach us, far eclipsing the previous single-star record holder whose light took 9 billion years to reach us.
Though Earendel is at least 50 times the mass of our Sun and millions of times as bright, we’d normally be unable to see it from Earth. However, the mass of a huge galaxy cluster between us and Earendel has created a powerful natural magnifying glass. Astronomers expect that the star will be highly magnified for years.
Earendel will be observed by NASA’s James Webb Space Telescope. Webb’s high sensitivity to infrared light is needed to learn more about this star, because its light is stretched to longer infrared wavelengths due to the universe’s expansion.
In this image, NASA astronaut Sunita Williams, Expedition 32 flight engineer, appears to touch the bright Sun during the mission’s third spacewalk outside the International Space Station. Japan Aerospace Exploration Agency astronaut Aki Hoshide is visible in the reflection of Williams’ helmet visor.
Today, April 12, is the International Day of Human Space Flight—marking Yuri Gagarin’s first flight in 1961, and the first space shuttle launch in 1981.
As we honor global collaboration in exploration, we’re moving forward to the Moon & Mars under the Artemis Accords.
If you’ve spent much time stargazing, you may have noticed that while most stars look white, some are reddish or bluish. Their colors are more than just pretty – they tell us how hot the stars are. Studying their light in greater detail can tell us even more about what they’re like, including whether they have planets. Two women, Williamina Fleming and Annie Jump Cannon, created the system for classifying stars that we use today, and we’re building on their work to map out the universe.
By splitting starlight into spectra – detailed color patterns that often feature lots of dark lines – using a prism, astronomers can figure out a star’s temperature, how long it will burn, how massive it is, and even how big its habitable zone is. Our Sun’s spectrum looks like this:
Astronomers use spectra to categorize stars. Starting at the hottest and most massive, the star classes are O, B, A, F, G (like our Sun), K, M. Sounds like cosmic alphabet soup! But the letters aren’t just random – they largely stem from the work of two famous female astronomers.
Williamina Fleming, who worked as one of the famous “human computers” at the Harvard College Observatory starting in 1879, came up with a way to classify stars into 17 different types (categorized alphabetically A-Q) based on how strong the dark lines in their spectra were. She eventually classified more than 10,000 stars and discovered hundreds of cosmic objects!
That was back before they knew what caused the dark lines in spectra. Soon astronomers discovered that they’re linked to a star’s temperature. Using this newfound knowledge, Annie Jump Cannon – one of Fleming’s protégés – rearranged and simplified stellar classification to include just seven categories (O, B, A, F, G, K, M), ordered from highest to lowest temperature. She also classified more than 350,000 stars!
Type O stars are both the hottest and most massive in the new classification system. These giants can be a thousand times bigger than the Sun! Their lifespans are also around 1,000 times shorter than our Sun’s. They burn through their fuel so fast that they only live for around 10 million years. That’s part of the reason they only make up a tiny fraction of all the stars in the galaxy – they don’t stick around for very long.
As we move down the list from O to M, stars become progressively smaller, cooler, redder, and more common. Their habitable zones also shrink because the stars aren’t putting out as much energy. The plus side is that the tiniest stars can live for a really long time – around 100 billion years – because they burn through their fuel so slowly.
Astronomers can also learn about exoplanets – worlds that orbit other stars – by studying starlight. When a planet crosses in front of its host star, different kinds of molecules in the planet’s atmosphere absorb certain wavelengths of light.
By spreading the star’s light into a spectrum, astronomers can see which wavelengths have been absorbed to determine the exoplanet atmosphere’s chemical makeup. Our James Webb Space Telescope will use this method to try to find and study atmospheres around Earth-sized exoplanets – something that has never been done before.
Our upcoming Nancy Grace Roman Space Telescope will study the spectra from entire galaxies to build a 3D map of the cosmos. As light travels through our expanding universe, it stretches and its spectral lines shift toward longer, redder wavelengths. The longer light travels before reaching us, the redder it becomes. Roman will be able to see so far back that we could glimpse some of the first stars and galaxies that ever formed.
Learn more about how Roman will study the cosmos in our other posts:
Telescopes located both on the ground and in space continue to dazzle us with incredible images of the universe. We owe these sharp vistas to a series of brilliant astronomers, including Andrea Ghez – an astrophysicist and professor at UCLA – and the “Mother of Hubble,” Nancy Grace Roman.
Did you know that stars don’t actually twinkle? They only look like they do because their light has to travel through our turbulent atmosphere to reach our eyes. As the atmosphere shifts and swirls around, the light from distant stars is slightly refracted, or bent, in different directions. Sometimes it’s directed right at us, but sometimes it’s directed a bit to the side.
It’s like someone’s shining a flashlight toward you but moving it around slightly. Sometimes the beam is pointed right at you and appears very bright, and sometimes it’s pointed a bit to either side of you and it appears dimmer. The amount of light isn’t really changing, but it looks like it is.
This effect creates a problem for ground-based telescopes. Instead of seeing sharp images, astronomers get fuzzy pictures. Special tech known as adaptive optics helps resolve pictures of space so astronomers can see things more clearly. It’s even useful for telescopes that are in space, above Earth’s atmosphere, because tiny imperfections in their optics can blur images, too.
In 2020, Andrea Ghez was awarded a share of the Nobel Prize in Physics for devising an experiment that proved there’s a supermassive black hole embedded in the heart of our galaxy – something Hubble has shown is true of almost every galaxy in the universe! She used the W. M. Keck Observatory’s adaptive optics to track stars orbiting the unseen black hole.
Roman’s Coronagraph Instrument will come equipped with deformable mirrors that will serve as a form of visual “autocorrect” by measuring and subtracting starlight in real time. The mirrors will bend and flex to help counteract effects like temperature changes, which can slightly alter the shape of the optics.
Other telescopes have taken pictures of enormous, young, bright planets orbiting far away from their host stars because they’re usually the easiest ones to see. Taking tech that’s worked well on ground-based telescopes to space will help Roman photograph dimmer, older, colder planets than any other observatory has been able to so far. The mission could even snap the first real photograph of a planet like Jupiter orbiting a Sun-like star!
Find out more about the Nancy Grace Roman Space Telescope on Twitter and Facebook, and learn about the person from which the mission draws its name.
Nearly 100 years ago, astronomer Bernard Lyot invented the coronagraph – a device that made it possible to recreate a total solar eclipse by blocking the Sun’s light. That helped scientists study the Sun’s corona, which is the outermost part of our star’s atmosphere that’s usually hidden by bright light from its surface.
Our Nancy Grace Roman Space Telescope, now under construction, will test out a much more advanced version of the same thing. Roman’s Coronagraph Instrument will use special masks to block the glare from host stars but allow the light from dimmer, orbiting planets to filter through. It will also have self-flexing mirrors that will measure and subtract starlight automatically.
This glare-blocking prowess is important because planets can be billions of times dimmer than their host stars! Roman’s high-tech shades will help us take pictures of planets we wouldn’t be able to photograph using any other current telescopes.
Other observatories mainly use this planet-hunting method, called direct imaging, from the ground to photograph huge, bright planets called “super-Jupiters” in infrared light. These worlds can be dozens of times more massive than Jupiter, and they’re so young that they glow brightly thanks to heat left over from their formation. That glow makes them detectable in infrared light.
Roman will take advanced planet-imaging tech to space to get even higher-quality pictures. And while it’s known for being an infrared telescope, Roman will actually photograph planets in visible light, like our eyes can see. That means it will be able to see smaller, older, colder worlds orbiting close to their host stars. Roman could even snap the first-ever image of a planet like Jupiter orbiting a star like our Sun.
Astronomers would ultimately like to take pictures of planets like Earth as part of the search for potentially habitable worlds. Roman’s direct imaging efforts will move us a giant leap in that direction!
About 15 years ago, our Hubble Space Telescope captured this ultra-deep field image of space, revealing thousands of galaxies tucked away in a seemingly empty spot in the sky.
Now, imagine this view of the cosmos – and all the mysteries in it – at a scale300 times larger than Hubble’s.
Roman recently released this gorgeous simulated image that gives us a preview of what the telescope could see. Each tiny speck represents a galaxy filled with billions of stars. And it’s more than just a pretty picture – scientists could learn a lot from an observation like this!
Since Roman can see much more of the sky at a time, it could create an ultra-deep field image that’s far larger than Hubble’s. So instead of revealing thousands of galaxies, Roman would see millions!
Roman’s ability to look far out into space with such an expansive view would help us better understand what the universe was like when it was young. For example, scientists could study a lot of cosmic transitions, like how galaxies switch from star-making factories to a quieter stage when star formation is complete and how the universe went from being mainly opaque to the brilliant starscape we see today.
And these are just a few of the mysteries Roman could help us solve!
At the bottom of a very dark swimming pool, divers are getting ready for missions to the Moon. Take a look at this a recent test in the Neutral Buoyancy Laboratory at NASA’s Johnson Space Center.
NASA astronauts are no strangers to extreme environments. We best prepare our astronauts by exposing them to training environments here on Earth that simulate the 1/6th gravity, suit mobility, lighting and lunar terrain they’ll expect to see on a mission to the Moon. Practice makes perfect.
The Neutral Buoyancy Laboratory at NASA’s Johnson Space Center is where astronauts train for spacewalks, and soon, moonwalks.
When astronauts go to the Moon’s South Pole through NASA’s Artemis program, the Sun will only be a few degrees over the horizon, creating long, dark shadows. To recreate this environment, divers at the lab turned off the lights, put up black curtains on the pool walls to minimize reflection, and used powerful underwater lamps to simulate the environment astronauts might experience on lunar missions.
These conditions replicate the dark, long shadows astronauts could see and lets them evaluate the different lighting configurations. The sand at the bottom is common pool filter sand with some other specialized combinations in the mix.
This was a test with divers in SCUBA gear to get the lighting conditions right, but soon, NASA plans to conduct tests in this low-light environment using spacesuits.
Neutral buoyancy is the equal tendency of an object to sink or float. Through a combination of weights and flotation devices, an item is made to be neutrally buoyant and it will seem to “hover” under water. In such a state, even a heavy object can be easily manipulated, much as it is in the zero gravity of space, but will still be affected by factors such as water drag.
The Neutral Buoyancy Laboratory is 202 ft in length, 102 ft in width and 40 ft in depth (20 ft above ground level and 20 ft below) and holds 6.2 million gallons of water.
