As of 2010, the closest known black hole to Earth is V4641 Sgr. According to Tega Jessa of Universe Today, V4641 Sgr is located in the Sagittarius arm of the Milky Way galaxy and was first discovered in 1999. This black hole is 1600 light years from Earth.Know More
Black holes are the last stage in a star's life cycle, forming when a star collapses under the weight of its own gravity, explains Jessa. They are discovered using radio telescopes, which detect radioactive emissions from matter that falls into them.
Based on Einstein's theory of general relativity, objects can fall or be pulled into a black hole, but they can never reappear. Because black holes are basically invisible, scientists rely on the observation of matter surrounding the possible location of a black hole.Learn more about Stellar Astronomy
The dynamo theory, which attempts to explain the origin of planets' magnetic fields, is supported by three lines of evidence: theoretical evidence from models, positive evidence from observations of planets with magnetic fields, and negative evidence from worlds without such a field. Some anomalous examples, such as Mercury, are exceptions.Full Answer >
A supergiant star forms when a main sequence star runs out of hydrogen atoms in its core. The star may begin to fuse helium atoms, and the change in heat and pressure can cause the star to expand many times its original size, creating a supergiant.Full Answer >
The brightest star, as viewed from Earth, is Sirius, and it appears bluish-white to the human eye. It is classified as an A1Vm star and shares the color spectrum with other class-A stars.Full Answer >
White dwarf stars form when a normal start stops burning and starts to shrink, but this only occurs when the solar mass of the star is between 0.07 and 1.4. The creation of the white dwarf is affected by both gravity and pressure, which work against each other trying to change the size of the star. Gravity wins the battle, which causes the star to shrink by pulling the outer layers inward.Full Answer >