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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
A:Stars vary in size from less than 8 percent of the size of the sun to those with diameters of more than 1,800 times that of the sun. In terms of mass, stars must have enough mass to support the nuclear chain reaction that takes place in the core of a star, which is about 10 percent of the sun’s mass. There is also a limit to how massive starts can grow, and scientists suspect that the limit is about 150 times the mass of the sun.
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.