Take a cosmic tour inside the images captured by NASA’s Webb telescope
NASA’s James Webb Space Telescope, the biggest and most powerful space telescope ever built, is now roughly a million miles from Earth, pivoting from one patch of the heavens to the other as it studies the target-rich environment that is our universe. The first handful of images were made public this week.
They’re stunning. They’re also loaded with information about the universe, the interplay of galaxies and the birth and death of stars.
Still, these images can be enigmatic to the average observer lacking a degree in astrophysics. What exactly are we looking at?
Let’s take a closer look.
The Deep Field
There are a lot of galaxies out there. This was the first image made public, demonstrating the power of the telescope to pick up extraordinarily faint, infrared light emitted within the first billion years of the universe. The image is centered on a galaxy cluster more than 4 billion light-years away, meaning its light was emitted roughly when the sun and Earth were formed. The galaxies in the cluster appear as creamy white blobs.
These galaxies collectively create a powerful gravitational warp in space that acts as a lens, magnifying and distorting more distant objects. That results in funhouse-mirror galaxies like the one on the upper right of the image that NASA astronomer Jane Rigby refers to as the Laffy Taffy.
In another part of the image, the lensing has turned a single galaxy into two mirror-image galaxies.
Light comes in many wavelengths along what is called the electromagnetic spectrum. Humans see in a narrow band known as the “optical” portion of the spectrum. The Webb telescope gathers light emitted in the infrared — long wavelengths that are largely inaccessible to the Hubble telescope and completely invisible to us.
ELECTROMAGNETIC SPECTRUM
Radio
Microwave
Infrared
James
Webb
Space
Telescope
Optical
spectrum
Hubble
Space
Telescope
Ultraviolet
X-ray
Gamma
Sources: NASA; European Space Agency;
Space Telescope Science Institute
WILLIAM NEFF/THE WASHINGTON POST
ELECTROMAGNETIC SPECTRUM
Radio
Microwave
Infrared
James Webb
Space Telescope
Optical
spectrum
Hubble Space
Telescope
Ultraviolet
X-ray
Gamma
Sources: NASA; European Space Agency;
Space Telescope Science Institute
WILLIAM NEFF/THE WASHINGTON POST
James Webb Space Telescope
Hubble Space Telescope
ELECTROMAGNETIC SPECTRUM
Gamma
Ultraviolet
Infrared
Microwave
Radio
X-ray
Optical spectrum
Sources: NASA; European Space Agency; Space Telescope Science Institute
WILLIAM NEFF/THE WASHINGTON POST
The Webb team scanned dozens of the reddest — most distant — galaxies in this image, and determined that one of them — a tiny, pixelated blob — emitted its light about 13.1 billion years ago, just 700 million years after the big bang. (Distances to such objects are inferred by their “redshift” — the extent to which the light has been streeeeeeeeeeetched by the expansion of space itself.)
The telescope obtained a spectrum of the galaxy, showing signs of oxygen, hydrogen and neon. Rigby said this kind of observation will clarify what was happening during the first billion years of the universe: “We really don’t know at all how big were those galaxies, how many of them there were.”
Southern Ring Nebula
Stars like our sun are nuclear fusion reactors that are remarkably stable over billions of years. But even they get old. This image shows what happens when a star dies. It’s shedding matter in its pulsing death throes.
These clouds of gas and dust, including complex molecules, are the raw material for stars and planets not yet formed.
NASA released two images, one in near-infrared (relatively close to the “visible” portion of the spectrum), and one in mid-infrared (farther along the spectrum).
In the near-infrared, the material forms a ring of foamy gas and dust, with hot, ionized gas dominating the central region. Rays of light shoot through holes in the outer ring.
Only one star is clearly visible at center. But this is a binary system — two stars, bound together by gravity.
In the mid-infrared, we see both. The dying one is fainter. The telescope reveals that it is enveloped in dust.
Our sun will look similar to this star in 5 billion years, explained Klaus Pontoppidan, Webb project scientist at the Space Telescope Science Institute.
“It’s a life cycle of stars,” Pontoppidan said. “This is the end for this star, but it’s a beginning for other stars and other planetary systems.”
The image includes an intriguing slash on one shoulder that astronomers came to realize is a distant galaxy. Although it’s a vast three-dimensional structure with billions of stars, we are looking at the edge of it, as if watching a Frisbee spinning away from us.
Stephan’s Quintet
The image has a whole lot of cosmos in it.
There are stars from our own galaxy — meaning they’re in the foreground, cosmically speaking.
Foreground stars in all the Webb images can be identified by their “diffraction spikes,” which are an artifact of the telescope’s design. The diffraction spikes on these images serve as something of a Webb telescope watermark.
In the middle distance is what appears to be a quintet of galaxies.
The one on the left is not part of the group but rather in the foreground, about 40 million light-years distant.
The telescope can discern individual stars in the foreground galaxy.
Many are aging “red giants” near the end of their lives, with well-documented properties that help astronomers estimate their true luminosity and distance to them. Such observations could improve the model scientists use to estimate the distance to objects across immense stretches of space.
The other four galaxies are about 290 million light-years distant. Two are merging. The gravitational interactions of the galaxies have sent streams of star-forming gas and dust toward intergalactic space
Strikingly, this image, like the “Deep Field,” contains countless galaxies scattered across the background. Look closely and you will see lovely, very distant spiral galaxies not unlike our own Milky Way.
The large galaxy at the top has a supermassive and highly active black hole at the core, feeding on its surroundings. The black hole itself does not emit light, by definition, but its gravitational field energizes the nearby gas, causing atoms to slam into one another and generate tremendous heat.
The accretion disk of this black hole shines with the energy of 40 billion suns, Rigby said: “Black holes emit no light, but their accretion disks sure do!”
Carina Nebula
Looks like a good place for a hike! Complete with brilliant star-filled sky. This nebula is a stellar nursery within our own galaxy.
“What looks like a starry night sky is part of an immense bubble has been carved from the cloud by the ultraviolet radiation and stellar winds from extremely massive, hot, young stars that have already formed,” said astronomer Amaya Moro-Martin of the Space Telescope Science Institute.
Streams of ionized material are flowing toward the top of the frame.
The Webb can see shock waves caused by newly ignited stars forming inside the cloud. Theirs is a hostile environment, for the same process that erodes away the cloud can halt star formation.
The Hubble telescope previously examined this section of the sprawling Carina Nebula, and the Webb team knew the sharply defined boundaries between the dusty cloud and the “open sky” would create a wowzer of an image.
But this is more than just pretty space art, said Joseph DePasquale, who is part of the team that processed the images at the Space Telescope Science Institute in Baltimore.
“We knew that, based on the Hubble image, that the landscape of this was going to look very much like a mountain range and the sky behind it. We knew it was going to be impactful from an aesthetic point of there,” DePasquale said. “But there was also a lot happening in terms of the physics. Webb could peer deeper into the clouds and uncover the mysteries of what’s happening.”
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