Ultraviolet light reveals dark secrets
The Hubble Space Telescope – with its ability to see in ultraviolet wavelengths – offers astronomers a unique tool to study the universe. As anyone who, as seen glowing metal, can attest, materials especially give off a range of colors when they heat up. Using this knowledge, astronomers can determine the temperatures of objects remotely by looking at the color emitted by the target. This is also the reason why stars are different colors – red stars are the coolest stars that are often seen, followed by middle-of-the-road stars like our Sun, while blue and white stars are the warmest.
But, just like our own Sun, temperatures in the atmospheric stars are significantly hotter than they are on the surface. The peak frequency given by this highly heated material is found in ultraviolet wavelengths of the electromagnetic spectrum – perfect for observations by Hubble.
Hubble’s sensitivity to ultraviolet light enabled researchers to study the layers above the star’s surface, which are so hot – more than 20,000 degrees Fahrenheit – they can not be seen at visible wavelengths. These layers are heated in part by the star’s turbulent convection cells bubbling to the surface, ”he said. Hubble team reports.
Betelgeuse has been sentenced to end her life as a supernova explosion. When this happens, the eruption will be easily visible from Earth. The red giant star is roughly 725 light-years from Earth – far enough away to prevent dangerous effects from invading our entire world. However, the supernova would probably create a ‘star during the day’ that could last for months at the end, and light from the star could cast shadows at night.
However, Betelgeuse is currently lost in the glare of the Sun, as seen from Earth (like Hubble, which creeps close to our planet).
Betelgeuse is not visible from mid-May to early August due to its close angle near the sun (as seen from Earth). This summer, thanks to the STEREO mission, Betelgeuse cannot hide in the glare of the sun.
“Although unobservable from Earth, Betelgeuse and surrounding stars are pictured by the Solar Terrestrial Relations Observatory (STEREO-A), which is about 69 degrees behind the Earth in orbit,” researchers write in an article published in The Telegram of the Astronomer.
Observations from the STEREO Space Observatory show Betelgeuse had a second, less dramatic, dimming from mid-May to mid-July. If the star expands again in late August and early September, Dupree will study the star with the STEREO Observatory, looking for signs of another eruption.
Supernova eruptions of supermassive stars like Betelgeuse form the heavy atoms where planets and life are built – including the carbon in our bodies.
It takes 725 light-years to traverse the distance Betelgeuse and earth. This means that when Betelgeuse exploded around the year 1295, when the Middle Ages ended, we will see light of that event almost … now.
This article was originally published on The Cosmic Companion due to James Maynard, founder and publisher of The Cosmic Companion. He is a New England native twisted desert rat in Tucson, where he lives with his beloved wife, Nicole, and Max the Cat. You can read this original piece here.
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