Star Explosions Measure The Growing Universe In & # 039; Ask A Spaceman & # 039;
Star Explosions Measure The Growing Universe In & # 039; Ask A Spaceman & # 039;
When the stars explode, they generate light that you can see throughout the universe. But these events, called supernovas, are not only beautiful to look at. They are also useful scientific tools to help researchers measure cosmological distances and speed, according to the Space.com columnist. Paul Sutterin his last episode of "Ask A Spaceman".
In episode 8 of the series Facebook Watch., Sutter talks about Type 1a supernovas, a particular type of stellar explosion. These happen when white dwarfs - the peels burned from stars similar to our sun - accumulate a certain amount of gas from a normal companion star. Once the white dwarf acquires a certain mass of gas, it explodes.
These explosions tend to be quite similar, with only minor variations, explains Sutter. And that makes them useful for calculating stellar distances. Astronomers use a measure called luminosity, which refers to the intrinsic brightness of an object. Type 1a supernovae have the same luminosity, so any change in apparent brightness is mainly due to their distance, how far or how close they are to Earth.
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Supernovas not only tell us how far they are located, but they can also provide a measure of how fast the universe is expanding. Or, as Sutter says, "it's almost like making a growth chart for a child, but for the whole universe."
When a Type 1a supernova explodes, astronomers can see what kind of elements were inside the star before it exploded. They use a technique called spectroscopy, which (simply speaking) tracks the elements of the explosion by observing the wavelengths of the light they produce. This is possible because each element produces a distinctive set of wavelengths.
As Sutter explained in past episodes, like this one about the "baby picture" of the universe - The universe is expanding with time. The objects that move away from us will have their light stretched towards the red side of the spectrum, which is known as "scroll to red"As a result, the elements of the supernova will also have their signatures redshifted." The degree of that redshift shows how quickly the supernova is moving away from us.
Astronomers are interested in learning about the rate of expansion of the universe because it tells us more about the nature of dark matter and dark energy, which is believed to constitute most of the universe. The problem is that dark energy and dark matter can not be detected through conventional instruments. Instead, astronomers measure dark matter by its gravitational effect on other objects, such as doubling light in space, and dark energy by the way it drives the expansion of the universe.
The episodes of "Ask a Spaceman" are released weekly on Wednesdays at 12 p.m. EDT (1600 GMT), so like your Facebook page or check back later to see more. Sutter also answers questions from readers in each episode. See the page for more information on previous topics covered by the program, such as the Big Bang, Pluto and Galaxy collisions.
Sutter is a cosmologist at Ohio State University and a senior scientist at the Columbus Ohio Center for Science and Industry. It has a long-playing podcast, also called "Ask A Spaceman". You can see all the past episodes of that podcast here.
Follow us @Spacedotcom, Facebook Y Google+. Original article about Space.com.
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