Lifetime of Earth: Planet vs Sun

[mersecske]

What is the liftime of a solid planet compared to the life of its sun?

 

[Nik_2213]

IIRC, unless it is subject to a mega-collision, or spirals into sun due tidal drag, the next 'planet killer' is the star's red-giant phase. The Sun will then shrink to a white dwarf. Loss of mass may cause an orbit shift, but not cast planet into deep space. If the star is somewhat larger than our Sun, it will go supernova, which may zap the planet. If planet survives that, it should just orbit the stellar remnant until heat-death...

 

[mersecske]

I mean, let's assume that we see a star on the sky (we don't know its color).
And we suppose that planets are around that star, if it is possible.
But what is the possibility that planets are around that star at this moment?
So the sun isn't to young or old?

b) And what is the same probability for any star in the galaxy,
independent of the fact that we can see or not?

 

[Nabeshin]

suppose that planets are around that star

what is the possibility that planets are around that star

What? This makes no sense, and I really don't know what you're asking.

A planet can exist indefinitely -- there are no forces which will ever cause it to dissipate or otherwise disrupt itself.

 

[pmacias]

The lifetime of a solid planet is significantly longer than the lifetime of its sun. While a solid planet can exist for billions of years, the sun has a finite lifespan of approximately 10 billion years. This is due to the fact that the sun is a main sequence star, meaning it generates energy through nuclear fusion in its core. As the sun burns through its fuel, it will eventually run out and become a red giant, expanding and engulfing any nearby planets before eventually dying out as a white dwarf.

On the other hand, a solid planet does not rely on nuclear fusion for its existence. Instead, it is primarily composed of solid materials such as rock and metal, which can withstand the test of time. While a planet may experience changes and transformations over its lifetime, it will not undergo a catastrophic event like the death of a star.

It is important to note that the lifetime of a planet also depends on its distance from its sun. Planets that are closer to their sun, like Mercury and Venus, may have shorter lifespans due to the intense heat and radiation from their star. However, planets like Earth, which are situated in the habitable zone of their sun, have the potential to support life for a much longer time.

In summary, the lifetime of a solid planet is significantly longer than the lifetime of its sun. While the sun has a finite lifespan, planets can exist for billions of years, making them crucial for the development and sustainability of life in the universe.