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| CREDIT - GOOGLE || IMAGE BY - SciTech Daily |
What is Hubble?
Hubble is an orbiting space telescope launched by NASA in 1990. It was designed to complement ground-based telescopes and carry out observational astronomy, ultraviolet photography, and spectroscopy from low Earth orbit for at least five years. So far it has been used for well over a decade, with no end in sight. One of Hubble's most important accomplishments was providing proof that there are supermassive black holes at the center of nearly all galaxies. Their observation was a significant milestone in astrophysics, possibly being one of biggest observations in recent history which pushed science into new territory and without a doubt will influence future generations of astronomers. Another major discovery made possible by Hubble was direct detection of light from exoplanets outside our solar system; something that had never been done before.
How do you measure distance across space?
One of Hubble’s main jobs is to use light, emitted by faraway objects, to determine their distance from Earth. Astronomers accomplish that feat using a tool called redshift. Objects with a high redshift—meaning they’re moving away from us quickly—are said to be receding. Objects with low redshift are approaching us and zipping away more slowly; galaxies with a negative redshift are moving closer. Redshift occurs because of an effect known as Hubble expansion: The universe is getting bigger all the time. Galaxies aren’t actually moving through space, but rather space itself is expanding between them. The farther apart two galaxies are, therefore, the faster they move apart due to Hubble expansion.
How did they know there was a blast?
The astronomers used NASA's Hubble Space Telescope to look at a white dwarf star called Stein 2051 B, which is located about 60 light-years from Earth. This type of star is very hot and compact -- roughly equal in size to Earth but 200,000 times more massive. Smaller than an atom, white dwarfs are crystallized remnants of normal stars that have used up their nuclear fuel and shed their outer layers. The research team was surprised to find an X-ray flare from Stein 2051 B every eight minutes with 10,000 times more energy than normally emitted by white dwarfs. The observations show that these flares come from a magnetic field around Stein 2051 B's surface, generated by its rapid spin on its axis.
Does this help explain dark energy?
The most recent data from Hubble confirms that our universe is expanding at an accelerating rate. What’s more, it suggests that about 70 percent of its overall mass and energy is in a form we can’t even identify. Scientists believe that all of this combined information points to a force they are calling dark energy, which helps drive not only universal expansion but also galaxy evolution. Though scientists have hypothesized about dark energy for years, its true nature remains unknown. One potential answer may lie in Einstein’s E=mc^2 equation, which equates matter with energy—could dark energy be a large amount of yet-to-be identified matter?
Wasn’t it Einstein who figured out why we see redshift when looking at distant stars and galaxies?
I’ll admit it: I couldn’t stand physics in high school. It was too hard, and way too many formulas. But to figure out why we see redshift when looking at distant stars and galaxies, you just need to remember one thing: E=mc2. If a star is moving away from us at a high speed, then according to Einstein's famous equation (which you learned about in physics), its energy must be increasing — hence its light becomes more red. That's all there is to it! Simple as that! And now that you're back on track with physics again, if anything else confuses you about what causes redshift or leads to E=mc2 being true — feel free to reach out!
What does this mean for us on Earth and our galaxy?
Astronomers have known for years that space is expanding. From decades of studying stars and galaxies, they learned that they are all moving away from each other in all directions, a consequence of what’s known as dark energy. Our current understanding, based on previous data collected by NASA’s Hubble Space Telescope (HST), indicates that for every 1 million parsecs (3.26 million light-years) between Earth and a faraway galaxy, space expands by another megaparsec (3.26 million light-years). At that rate, it would take our galaxy tens of billions of years to move 1 Mpc from us and our galaxy would be 100 billion times its present size when it finally became unrecognizable as such.
How can I learn more about dark energy, astronomy, and all things outer space related?
There are a couple of ways to learn more about space and astronomy. If you enjoy reading, I’d recommend taking some time to peruse Wikipedia or one of many comprehensive books on space like The Illustrated History of Space Travel. Another option is to watch documentaries on Netflix (or any other streaming service) like How It's Made: Space or The Universe series from Discovery Channel. Another great way to learn more is by attending events at your local observatory or planetarium, which often have talks from experts in their field. While learning as much as possible about outer space is something that can take a lifetime, it doesn't hurt to start now!