astronomy question !!!!??

Question

is it true that the earth will come to its end around the same time the sun is about to die? because i hear that when the sun starts running out of hydrogen itll start to expand to about 100x its size and as it does itll consume the first three inner planets ? am i right ?

Answer 1

Probably right. We don't have an exact scale of red giant growth to stellar mass, yet. But many red giants are larger than the orbit of Mars.

Answer 2

yes. As the Sun ages, helium collects in its center and eventually, when about 10 percent of the hydrogen has been converted to helium, the nuclear fusion reactions will stop producing energy. At this point he equilibrium between the total pressure force directed outwards and the gravitational force directed towards the centre of the Sun will be imbalanced and the core of the Sun will start slowly collapsing under its own gravitational attraction. Fusion moves outward to a shell surrounding the core, where hydrogen-rich material is still present. The gravitational energy from the collapse will be converted into heat causing the shell to burn vigorously and so the Sun's outer layers will swell immensely. The surface of the sun will now be far removed from the central energy source and so cools and appears to glow red. The Sun will now be a red giant. For a few hundred million years, the expansion of the outer solar layers will continue, and the Sun will engulf the planet Mercury. The temperatures on Venus and the Earth will rise tremendously.
Hydrogen fusion in the shell will continue to deposit helium into the core, which will become even hotter and more massive. In the Sun's core nuclear fusion of helium into carbon and oxygen will trigger even further expansion of its outer layers. The helium-rich core is unable to lose heat fast enough and becomes unstable. In a period of just a few hours the core will get too hot and will expand explosively. Outer layers of the Sun will absorb the core explosion but the core will no longer be able to produce energy by thermonuclear burning. Helium fusion will then continue in a shell and the structure of the Sun would look like an onion: An outer, hydrogen-fusion layer and an inner, helium-fusion layer which surrounds an inert core of carbon and oxygen.
The sun may repeat this cycle of shrinking and swelling several times until finally the sun expands a last time and after about 30 million years swallows Venus and the Earth. It's outer layers will keep expanding outward until as much as half of the sun's mass gets lost into space.

These sources give good explanations of the evolution of the sun.

Answer 3

Right, the current theory says that the Sun, nearing the end of its life, will expand to many times its size, most likely engulfing the Earth. But this is a few billion years away, so this is assuming that no other huge geological disasters happen in the meantime. After the Sun is done expanding, it will shrink to an extremely small size (comparatively to now) and will emit nearly no light, so either way, after the Sun dies, the Earth will not be a very nice place to live.

Answer 4

Kent H's answer is almost completely wrong. Our Sun does not have enough matter to explode in a supernova. It will live out its last years as a tiny white dwarf, but before it does that it will have expanded out past Earth's orbit as a red giant.

Interestingly, Red Giants in that stage are so large, cool, and diffuse that they do not have a well-defined "border" like our sun does now. It's incredibly unlikely, but theoretically I believe it's possible that a planet could survive and orbit within the radius of a red giant star. I think. Possibly. The planet would be incapable of supporting life, of course.

Answer 5

This is true in a way, but once the sun expands, it loses gravitational pull, which leads to the earth's orbit in creating more distance. The sun is also believed to expand right around the Earths orbit and not much farther, so the Earth may be spared, but this is still about 10 billion+ years away.

Answer 6

The sun will first become a red giant and consume the earth,

but eventually the gravitational pull of all the mass will converge into a small star and become a white dwarf.
This star has the most dense mass in the universe.
All the mass causes greater and greater heat and after thousands of years, it will explode in a supernova.

So the earth will be long gone before the star is about to die.

Answer 7

Yes. But we will be dead by then. It will take the Sun 5 billion years for the Sun to explode and create a black hole that sucks all the planets in. When it runs out of helium and hydrogen.

Answer 8

Yes, that is what would happen to the sun in several hundreds of millions of years. The sun will expand to a size just short of the Earth's orbit. Event though it won't envelop us, it will vaporize us because of proximity.

Answer 9

This is essentially correct. The outer atmosphere of the sun will engulf Earth, and the added friction will slow it's orbit, making it fall into the sun.

Answer 10

yes the sun will eventually turn into a red giant and engulf all the inner planets. then it will destroy the out planets but thats a long time away