STRETCH OUT YOUR hand and raise your pinky finger.
Now imagine an area roughly 10% as large as your fingertip.
That’s the size of a patch of space shown below, and astronomers behind the Chandra X-ray space telescope have photographed it 102 times over the past 17 years. In total, they’ve observed this tiny corner of the universe some 81 days, carefully merging all the photos together to create the image here, which was released this week.
What did they find?
Black holes. Hundreds and hundreds and hundreds of supermassive black holes:
Supermassive black holes range anywhere from thousands to billions of times more massive than the sun. They hide out in the centres of large galaxies.
They’re also extraordinarily important to how we got here, since they coevolve with galaxies such as the Milky Way and influence the destinies of their billions of stars, asteroids, comets, moons, and planets — plus any life that happens to exist on such objects.
“The central region of this image contains the highest concentration of supermassive black holes ever seen, equivalent to about 5,000 objects that would fit into the area of the full Moon and about a billion over the entire sky,” according to the photo release by the Chandra team, which was issued by the Smithsonian Institution.
The image above shows a piece of the sky in the constellation Fornax, and it’s about 16 arcminutes across. By comparison, your pinkie’s fingertip is about 60 arcminutes across and the moon is about 31 arcminutes across. Chandra says about 2,076 galaxies (and their supermassive black holes) are lurking in the photo, which they called “the deepest X-ray image ever obtained.”
The dots reveal the locations of the supermassive black holes.
Astronomers can “see” these monsters because they round up stars, gas, and dust in a region called an accretion disk, which gets very hot and emits the X-rays. Low-energy X-rays are shown in red, medium-energy in green, and high-energy in blue.
These galaxies are between 11.9 and 12.9 billion light-years away from Earth — so distant it’s like looking back in time.
Put it all together, according to two recent studies, and the data shows giant black holes at the centres of galaxies probably didn’t start small (roughly 100 times the sun’s mass) and grow by gobbling up gas, dust, and stars.
Instead, they had to begin at huge sizes, or “about 10,000 to 100,000 times that of the Sun,” according to the release.
How did they do that? No one is really sure, and the Chandra survey is part of astrophysicists’ effort to figure that out.
In the meantime, we can look up at the night sky and imagine all of those X-ray-emitting monsters staring back at us.
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