Stellar Astronomy

A:

Betelgeuse is 4,000 degrees Fahrenheit cooler than the sun, measuring an effective temperature of 6,000 degrees Fahrenheit compared to the sun's 10,000 degrees Fahrenheit. Despite its lower temperature, Betelgeuse's diameter of 600 million miles is around 700 times the diameter of the sun.

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  • Where do black holes lead to?

    Q: Where do black holes lead to?

    A: Strictly, black holes don't actually lead anywhere, as they are not holes in the common sense of the term. According to the Harvard Smithsonian Center for Astrophysics, black holes are regions of the universe in which matter has become so dense that nothing, not even light, can escape its gravitational pull. Within this volume, the original matter has become so compact that it can fairly be said to have disappeared.
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  • Why does Carl Sagan say that we are "star stuff"?

    Q: Why does Carl Sagan say that we are "star stuff"?

    A: Sagan says that humans are "star stuff" because every living body is made of several elements that were forged in ancient stars. Apart from hydrogen and lithium, every element used in the chemistry of life was originally synthesized in stars that exhausted their hydrogen fuel and began fusing heavier nuclei.
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  • How might emission spectra be used to study stars?

    Q: How might emission spectra be used to study stars?

    A: The emission spectra of gases can be used to study stars because the absorption spectra of stars are the exact opposite of the emission spectra of the gases that compose the stars. When the light from a star is split into its component colors, it creates a continuous spectrum except for specific missing colors. These missing colors are the same ones emitted by heated gases in laboratory settings.
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  • What is a stellar nebula?

    Q: What is a stellar nebula?

    A: A stellar nebula is a cloud of superheated gases and other elements formed by the explosive death of a massive star. Stellar nebulae emit brilliant waves of infrared light generated by dust particles within the cloud.
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  • Are the stars bigger than the Earth?

    Q: Are the stars bigger than the Earth?

    A: The majority of stars are much larger than the Earth. Even the Sun, which is a relatively average star, is many times the size of the Earth. The largest star is 1,800 times as large as the Sun.
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  • What is a blue dwarf star?

    Q: What is a blue dwarf star?

    A: A blue dwarf is a hypothetical star that is created from a red dwarf star that has exhausted most of its hydrogen fuel supply. Red dwarf stars fuse hydrogen very slowly, and they can allow a large amount of their hydrogen to be fused, which means that the creation of a blue dwarf star takes an incredibly long time.
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  • Can a star become a red giant more than once?

    Q: Can a star become a red giant more than once?

    A: Stars can go through two red giant phases. After stars burn up hydrogen and become red giants, the core may shrink and allow helium to be used for fuel, returning them to main sequence stage. When the new fuel is burned up, the star may return to a red giant.
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  • How are interstellar bubbles made?

    Q: How are interstellar bubbles made?

    A: Interstellar bubbles are made when stellar winds caused by massive stars or supernovae push the interstellar gas around them outwards in a bubble shape. Stars clustered close enough together form giant bubbles when their bubbles merge. These giant bubbles are known as superbubbles.
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  • How is an orbit formed?

    Q: How is an orbit formed?

    A: An orbit is formed when a celestial body passes by a larger one at such a distance that its velocity is in perfect balance with the larger one's gravity. This means that the smaller object doesn't fall, nor does it continue in space. Instead, it travels in an ellipse or circle around the larger object forever.
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  • How many light years away is the farthest star?

    Q: How many light years away is the farthest star?

    A: The most distant star ever observed is any contained in Galaxy MACS0647-JD, located 13.3 billion light years from earth. This galaxy is located at such a great distance that even with the aid of powerful orbital telescopes, it is not yet possible to make out individual stars.
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  • How do auroras form?

    Q: How do auroras form?

    A: Auroras are formed when charged particles that are emitted from the sun hit the Earth's magnetic field and the atoms in the atmosphere. This interaction causes the gases in the atmosphere to give out photons of different energies, which can be seen from Earth as light.
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  • What is dust cloud theory?

    Q: What is dust cloud theory?

    A: Cloud theory, sometimes called nebula theory, is a model of the early solar system that describes the formation of the Sun and planets. In this model, the solar system formed out of a cloud of dust in a protoplanetary nebula known as a stellar nursery.
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  • In what stage of evolution are most stars?

    Q: In what stage of evolution are most stars?

    A: About 90 percent of all stars are main sequence stars. Main sequence stars are the fourth stage of a star's evolution. Nuclear fusion occurs during this stage of a star's life cycle; this is where a star burns hydrogen to make helium.
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  • What is a white dwarf?

    Q: What is a white dwarf?

    A: A white dwarf is a star at the end of its life cycle that can no longer fuse carbon due to insufficient mass and temperature. It may also be referred to as a degenerate dwarf.
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  • How hot is Betelgeuse compared to the sun?

    Q: How hot is Betelgeuse compared to the sun?

    A: Betelgeuse is 4,000 degrees Fahrenheit cooler than the sun, measuring an effective temperature of 6,000 degrees Fahrenheit compared to the sun's 10,000 degrees Fahrenheit. Despite its lower temperature, Betelgeuse's diameter of 600 million miles is around 700 times the diameter of the sun.
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  • What makes the stars appear to move from east to west across the night sky?

    Q: What makes the stars appear to move from east to west across the night sky?

    A: The stars appear to move from east to west across the night sky because as Earth rotates, the sky is observed as rotating, according to Astronomy Education at the University of Nebraska–Lincoln. Observers on Earth, in both the northern and southern hemispheres, see objects in the sky move counter-clockwise.
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  • Why can't we see stars during the day?

    Q: Why can't we see stars during the day?

    A: Most stars cannot be seen during daylight hours because light from the sun is brighter than the relatively faint light from the other stars. This is largely a result of the Earth's atmosphere scattering the sun's light so that every point in the sky seems brighter than distant stars.
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  • What does supernova mean?

    Q: What does supernova mean?

    A: A supernova is a star that has exploded at the end of its life. Only special stars undergo supernovae; the sun will not experience a supernova when it dies. Supernovae occur in stars that have more than 10 times the mass of the sun.
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  • What types of stars end their lives with supernovae?

    Q: What types of stars end their lives with supernovae?

    A: The two types of stars that end with supernovae are white dwarfs and massive stars that are at least eight times the mass of the sun. Each of these types of stars undergoes a thermonuclear reaction at the end of its life.
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  • What is the approximate number of known galaxies in our local group?

    Q: What is the approximate number of known galaxies in our local group?

    A: There are between 30 and 54 known galaxies in the local group to which the Milky Way belongs. Some astronomers include dwarf galaxies in this number.
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  • Why are stars different sizes?

    Q: Why are stars different sizes?

    A: Stars have different sizes due to their mass and their individual stages during their evolutions, according to the Nova Celestia. Giant stars are particularly varied in size, as they have reached a stage wherein they start fusing helium — once the hydrogen runs out — into heavier elements in their core, causing them to grow larger.
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