For those that are interested in both X-ray technology and astronomy, exciting things are happening to unlock the secrets of the known universe. While spacecrafts like the Hubble Telescope might be more widely know, X-rays are commonly used in space as well. This is because no X-rays can penetrate through the Earth’s atmosphere. In a sense, this works in our favor, since cosmic rays are happening all the time, and we don’t need to worry about any of their affects. But it makes observing these rays all the more trickier.
How X-ray Astronomy Works
X-ray astronomy can be used to answer many of astronomers questions. A few of these include:
- Why do some stars seem to have magnetic fields still from their period of formation while other stars seem to generate new magnetic fields frequently?
- Why is the corona of the sun so much hotter than it’s surface? (see more about this below)
- Where is the source of all these cosmic X-rays? Can the source be discovered by searching with other wavelength forms (like infrared or optical) to find possible coincident objects?
Maybe all these questions will only lead to more questions, even when they’ve been answered. But let’s first go back a step and take a look at how X-ray astronomy actually works. For a quick primer, here’s NASA’s simple yet elegant explanation:
“From space, x-ray telescopes collect photons from a given region of the sky. The photons are directed onto the detector where they are absorbed, and the energy, time, and direction of individual photons are recorded. Such measurements can provide clues about the composition, temperature, and density of distant celestial environments.”
So what this means is that X-ray telescopes can use this information to discover black holes, neutron stars, binary star systems, supernova remnants, stars, comets, and more. Learning about the number of photons detected, the energy of the photons, and how fast the photons are detected uncovers the secrets about the objects emitting them.
A Brief History
- 1949 – The first X-rays emanating from the sun’s corona, the outer layers of the sun’s atmosphere, are discovered.
- 1962 – The first cosmic X-rays are discovered, emanating from the constellation Scorpius.
- 1970 – Uhuru is launched, the first satellite dedicated to observing the sources of cosmic X-rays. More than 400 sources are discovered between December 1970 and March 1973. Throughout the rest of the decade, more and more satellites are launched not only by NASA, but by the US Department of Defense, the United Kingdom, and the Netherlands as well.
- 1990 – Roentgensatellite (ROSAT) is launched by Germany, increasing the number of known cosmic X-ray sources to over 125,000.
- 1993 – Advanced Satellite for Cosmology and Astrophysics (ASCA) is launched by Japan, and will eventually be the first satellite to find evidence of the gravitational redshift due to the strong gravitational field around a black hole.
- 1999 – The Chandra X-Ray Observatory is launched by NASA; it is considered one of the more important satellites launched to date. It’s discoveries have been countless, and have aided astronomers in theorizing how galaxies are formed, and has led to investigations related to dark matter, the abundant and invisible non-emitting or reflecting material that makes up the majority of matter in the universe.
The rate at which we find new discoveries about outer space continues to grow at a rapid speed. Within the past few months, there have been two major discoveries thanks to X-ray technology.
- While researching data received by the European Space Agency’s aircraft XMM Newton, scientists discovered a spike in X-ray emissions coming from two celestial objects, the Andromeda galaxy and the Perseus galaxy cluster. There is no correlation between this signal and any other known particle or atom, and researchers suggest that this finding may have been produced by dark matter.
- NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) recently took an X-ray photo of the sun, visibly showing X-ray emissions produced by the sun. Studying these findings, scientists hope to discover why the sun’s corona (1.8 million degrees Fahrenheit) is so much hotter than the sun’s surface (10,800 degrees Fahrenheit). X-ray photos of the sun may also be able to find evidence of dark matter within the center of the sun.
As you can see, X-rays play a large role in unlocking the secrets of the universe. We’ve been able to prove more in the past 55 years than the entirety of human existence before that. One can only imagine how so much more is left to be discovered.