Regiomontanus
Ματαιοδοξία ματαιοδοξιών! Όλα είναι ματαιοδοξία.
Over the lifetime of a star like ours (spectral type G2), that mass loss is about 0.06% of what it started with. So planetary orbits will not change a huge amount.
-
Welcome to Religious Forums, a friendly forum to discuss all religions in a friendly surrounding.
Your voice is missing! You will need to register to get access to the following site features:- Reply to discussions and create your own threads.
- Our modern chat room. No add-ons or extensions required, just login and start chatting!
- Access to private conversations with other members.
We hope to see you as a part of our community soon!
Red Giant Sun
- Thread starter SalixIncendium
- Start date
Over the lifetime of a star like ours (spectral type G2), that mass loss is about 0.06% of what it started with. So planetary orbits will not change a huge amount.
Aupmanyav
Be your own guru
I am not talking about a black-hole. Sun will never be a black-hole. It will finally be a white dwarf and then a blacfk dwarf. No event horizons involved.
Subduction Zone
Veteran Member
For this simple Newtonian physics is accurate enough. The mass of an object that one rotates around is all that matters. Well as long as one is not inside that body. When it comes to orbits the Sun can be treated as a point mass for the planets. Again, you are going to have some minor relativistic problems with Mercury's orbit if one does so, but for this discussion. that error is negligible.
I could go over the math, but it is covered by the Shell theorem:
Shell theorem
Subduction Zone
Veteran Member
Darn! Two hours too late
Even though I doubt humans will be living on Earth when all this happens, but what kinds of effects might we see when Mercury and then Venus are consumed? Would either of those being destroyed cause problems? I suspect by then the Earth will be too hot anyway but ...
Regiomontanus
Ματαιοδοξία ματαιοδοξιών! Όλα είναι ματαιοδοξία.
Correct. Your edit to your previous post has clarified that you were not referring to BHs.
Not particularly. First of all, the expanded sun will be huge but not very dense. There would be some increase in the friction in their orbits, so they would gradually spiral in to the center, but that would take a fairly long time to do. The temperature at the surface of a red giant is 'only' about 3-4000K, so would not even cause the break up of those planets.
One amusing aside is that if the sun were replaced by a BH of the same mass, the orbits of the planets would not be affected. The gravitational effect at a distance would be the same.
Subduction Zone
Veteran Member
Regiomontanus
Ματαιοδοξία ματαιοδοξιών! Όλα είναι ματαιοδοξία.
Many of the details of what exactly will happen are not clear. However, in 'just' 2 billion years or so (a few billion years before it leaves the 'main-sequence') the sun will have heated up enough to boil off the oceans here. So when the sun does eventually run out of hydrogen to fuse and then, eventually, create a planetary nebula (new estimates show the sun is barely massive enough for that to happen), our planet will be long dead already.
I was also forgetting about the increase in heat from the Sun, such that Earth would be uninhabitable long before the Sun expands.
A mere billion years according to some, but perhaps we will have found some piece of rock on which to shelter.
Heyo
Veteran Member
Gravity wells are for losers.A mere billion years according to some, but perhaps we will have found some piece of rock on which to shelter.
Gravity Wells
OK - we'll have mobile homes by then.
Subduction Zone
Veteran Member
Or vastly improved air conditioner technologyOK - we'll have mobile homes by then.
Heyo
Veteran Member
Should be possible in a billion years. The problem is that we probably need it in 50 years.Or vastly improved air conditioner technology
Suave
Simulated character
Based on the amount of solar mass lost as sol converts her mass into energy, I've figure the Earth's orbit is approximately 1.5 centimeters further away from the Sun than what the Earth's orbit had been during its previous orbit. This means the Earth's orbit around the Sun will be at an average distance of 150.1 million kilometers in a few billion years. However, the Sun's surface will have expanded to a radius of 150.1 million kilometers after exhausting her hydrogen by then and subsequently make contact with Earth.
Suave
Simulated character
Or vastly improved air conditioner technology
In a thousand generations from now, Tau Ceti will be approximately 10 light years away from Earth. This would be within a hundred years range of a multi-generational fusion propelled rocket ship travelling an appreciable fraction of light's speed. The mean surface temperature of Tau Ceti E with an Earth-like atmosphere would be approximately 154 degrees Fahrenheit. [1] Higher elevation regions a couple of miles above Tau Ceti E's sea level would be hardly bearable at nearly 100 degrees Fahrenheit without air conditioning. Yes, improved air conditioner technology would be needed there.
- Giovanni F. Bignami (2015). The Mystery of the Seven Spheres: How Homo sapiens will Conquer Space. Springer. ISBN 9783319170046., Page 110.