Just read a question about our sun turning supernova and alot of people indicate the sun has got halfway through its life cycle is this true and how do we know?
2006-09-30 16:18:54 · 5 answers · asked by bladesmanlou 2 in Science & Mathematics ➔ Astronomy & Space
Based on the mass of the Sun (which basically tells us how much hydrogen it has available for fusion), we can estimate how long it will live… Turns out it’s something like 10 billion years. After that, it will run out of fuel and become a white dwarf (perhaps producing a planetary nebula in the process, although that’s increasingly uncertain). It’s not quite massive enough to go supernova—which is a good thing, because stars that have enough mass to die in supernovae don’t live nearly as long as the Sun.
Since the Sun and Earth formed at roughly the same time, we can use our estimates for the age of Earth—about 4.6 billion years—to determine that the Sun is about halfway through its life cycle.
Ryan Wyatt
Rose Center for Earth & Space
New York, New York
2006-09-30 16:30:08 · answer #1 · answered by ryan_j_wyatt 3 · 1⤊ 0⤋
They start with the assumption that the Sun was all hydrogen.
Based on the Sun's mass, they can determine the rate at which hydrogen will fuse into helium and other heavier elements.
Then they use spectroscopy to find out how much hydrogen has fused already. Based on how much hydrogen is left and the rate at which it is used up, they determine the age. Using this same info they can estimate when the Sun will run out of fuel.
2006-10-01 17:04:13 · answer #2 · answered by Demiurge42 7 · 0⤊ 0⤋
The current ratio of hydrogen to helium (revealed by spectroscopic analysis) tells us how how long a star has been fusing hydrogen and how much longer a star will take to exhaust its hydrogen supply.
The Sun is a Main Sequence G2 star, There are about 1 million of those in the Milky Way alone, so there are plenty of examples to compare the sun with.
2006-10-03 06:19:01 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Long story short. A star's life depends on its mass. The more the mass a star has, the faster it burns its "fuel". By knowing the mass of our sun, the scientist can predict how long our sun will live. See the following link for detail.
http://en.wikipedia.org/wiki/Star#Age_and_size
2006-09-30 23:41:01 · answer #4 · answered by muon 3 · 0⤊ 0⤋
the sun does not have a cycle it hasn't got any legs to ride with
2006-09-30 23:21:58 · answer #5 · answered by dave r 1 · 0⤊ 1⤋