The sun is almost entirely composed of hydrogen and helium. Hydrogen accounts for about 75 percent of the sun's mass, with the other 25 percent being almost entirely helium. Other elements, such as oxygen and carbon, do exist in the sun, but at such low concentrations as to be insignificant.Know More
Helium was first detected in the sun, which is why the element was called "helium," after Helios, the sun god in Greek mythology. Helium is present as a by-product of the sun's nuclear processes. The hydrogen that makes up the bulk of the sun's composition is very hot and exists in an excited phase of matter known as plasma.
Under less energetic conditions, hydrogen atoms encounter and repel each other in a weak fashion. In the crushing pressure and blazing heat of the sun's core, however, the hydrogen atoms aren't able to bump off each other, so they strike and stick together with sufficient force to form a new, heavier atom. This process, known as fusion, releases the energy that eventually pours out of the sun and has gradually been converting the giant star's hydrogen into helium for the last several billion years.
Despite the fact that a quarter of its mass has already been converted into helium, the sun still has enough fuel to burn for a long time. The existing store of hydrogen is sufficient to keep sun burning for at least another 5 billion years.Learn more in Our Sun
The sun formed from a collection of gas and dust that pulled together by mass gravitation; the extreme pressure caused by this great mass produced a nuclear fission reaction that fueled the sun and continues to keeps it burning. The primary elements that make up the sun are hydrogen and helium. Scientists theorize that the shock wave from a large supernova drew together the dust particles that became the sun.Full Answer >
Technically speaking, the sun is, in fact, not a source of inexhaustible energy, since every star eventually burns out. However, the sun's internal fuel supply will keep it burning for at least six billion years, enough to be considered inexhaustible for all practical purposes. The sun's nuclear furnace provides as much as 174 petawatts of solar energy to the planet, approximately 70 percent of which is absorbed by the surface.Full Answer >
The red or orange tint the sun sometimes takes is caused by small particles in the Earth's atmosphere. The sun appears redder at sunset because the light must pass through a greater thickness of air compared to when the sun is at its zenith.Full Answer >
Europa is one of Jupiter's four large moons, and its distance from the sun is always the same as Jupiter's, plus or minus the radius of Europa's orbit. Depending upon its position in orbit, Europa is 779.4 million to 780.6 million kilometers from the sun.Full Answer >