If you think we know everything about the universe, you couldn’t be more wrong.
Astronomers are finding mind-blowing facts about the universe all the time and discovering things they have never seen before, even in galaxies that are widely studied.
NASA’s Chandra X-ray Observatory has allowed astronomers to identify objects in faraway galaxies that could answer some serious questions about the universe.
NASA’s Chandra X-ray Observatory
Chandra is NASA’s space telescope specifically used for identifying X-ray light, and is called one of the “Great Observatories” that NASA has created, alongside the famous Hubble Telescope.
Where it differs from normal telescopes is in its location: it lives not here on Earth, but out in space, launched on 23 July 1999 aboard the Space Shuttle Columbia.
Why is it in space?
Well, because the Earth’s atmosphere blocks most X-rays, the telescope has to work from outside Earth to be able to detect these X-rays. So it stays out there, studying hot, energetic objects such as exploded stars, black holes, neutron stars, and hot gas in galaxies.
But if the telescope has been up in space for so long, how has this new discovery been hiding in plain sight?
How this new discovery was found
A team led by Mustafa Muhibullah at the University of Alabama had an idea to look again at old data, to see if they had missed anything in the years before.
This idea came from the fact that astronomers seem to ignore or discard certain data. Mainly the lowest-energy X-rays because at this energy, the detectors they use do not respond very well and are often shaky.
But astronomers at the University of Alabama decided it was worth investigating these types of low-energy channels instead of simply ignoring them.
So a team started searching NASA Chandra‘s public archive, focusing mainly on the Andromeda galaxy, our closest large neighbor galaxy, and 5 others, to look for these faint images.
It was suspected that bright ultraviolet objects could be hidden by the gas between stars, and that their soft X-rays could reveal them.
So they started looking for points of light that shone in the faintest shots and then disappeared in the stronger ones.
What they found was utterly unexpected.
Muhibullah and his team have never seen objects act this way
Not just a few, but dozens of objects matched this pattern! The search led by Mustafa Muhibullah of six nearby galaxies showed a vast number of objects that were almost all previously unknown.
They found objects in busy areas where new stars form, and in quieter areas full of older stars. How had they never seen them before?
The answer lies in their faintness: for X-rays to catch such soft light is extremely difficult. There is a lot of hydrogen and helium gas around them, which actually absorbs the light that they give off.
And so, a great 84 X-ray sources were found that have been hidden from us for so many years. These types of discoveries can rewrite what scientists believe about the universe.
Their presence is not the only shock; Scientists also think they emit strong ultraviolet radiation, which can strip electrons from the gas between stars. This process remains only a possibility, as it has not been studied properly yet.
So these 84 X-ray sources found in six galaxies give off very faint X-ray energy but appear to put out a great deal of ultraviolet light. This could have an effect on the stars around them, and further study needs to be done to prove this. This discovery is a great reminder that old archives can still surprise us, just like these old radio recordings that were analysed.
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