As the sun is losing millions of tons of matter every second, are the planets' orbits moving away from the sun

Question

... given that gravitational strength is related to the mass of a body.

Answer 1

You are quite right.
Since it formed about 4.5 billion years ago, the Sun has converted around 100 Earth-masses of matter into energy.
This may seem like a lot, but its only .03% of its total initial mass. So the gravitational field of the sun is only a tiny fraction of a percent less than when the solar system formed.

However, in another 6.5 billion years the sun will have expanded to a red giant and through the increased solar wind it will have lost a total over 30% of its mass.
By then, the Earth will have moved out to orbit around 1.67 AU, and the other planets will have moved out farther as well. Except for Mercury and Venus which will both have been absorbed by the bloated sun by then.

Answer 2

Yes gravity is directly proportional to mass but 4 million tons is a fairly insignificant % of the Sun's total mass. Actually let's do some maths just for fun: 1.9891 × 10^30 kilograms I'm going to be approximate and say roughly 1 tonne = 1000 kgs. (it actually varies depending on what you mean by ton or tonne) 4,000,000,000 kg/s * 1 billion years = 1.261×10^26 kg (kilograms) Let's do some quick rounding for the sake of simplicity. So how much will the Sun weigh? 1.9891 x 10^30 - 1.261 x 10^26 = 1.9890 x 10^30 So it only makes a difference to the mass at the fourth significant figure, that corresponds to a 0.01% reduction in mass or gravity. If that directly corresponded to an increase in our orbit (which it won't) we'd only be 0.01% further away from the Sun than we are. So a year wouldn't last 365.25 days it would last 365.286525 which means we might need an extra leap day in a century. The normal difference between perihelion and aphelion for the Earth is a factor of 1.034 (i.e. 3.4% further away in June than in December) so climatologically are we really going to notice 0.01% change? Not a lot will be differnt in 1 billion years time, in terms of Earth's orbit or its distance from the Sun, the time to worry will be in 5 billion years time when there is so much Helium in the core that it starts to fuse Helium swelling up to a red giant.

Answer 3

The planets are slowly moving away from the sun due to the centrifugal force created by orbiting the sun. The diminishing mass of the sun has no significant effect.

Answer 4

well gravity is effected by mass and how close it is. the sun is expanding as well so it is getting a little closer in that respect. the universe is expanding but our solar system for the most part is staying the same. but yes you are correct the sun is losing mass yet getting bigger and will swallow us up long before it loses us. by then I'm sure people will not be here anymore for it to matter.

Answer 5

Nice question.

The answer is yes but only if the angular momentum of the Earth is conserved. I would have thought that the tidal forces (with the sun not the moon) and a small amount of friction would slow us down and hence move us in. The big question is which is the greater effect?

Answer 6

Simply, yes.
But its neglible, even over thousands of years.

Answer 7

The sun is just transforming the mass of the hydrogen in helium and some matter is lost in the form of energy and heat, but is its minimal. So, no need to worry about it.

Answer 8

well at one point in the planets orbit the planet is further away from the sun but only about 5 million km. witch isn't really that much of a difference. so no the planets aren't moving further away from the sun.

Answer 9

Away. As the gravitational pull weakens the planets are moving farther away.

Answer 10

Elliptical orbit eliminates whatever gravitational pull is lost through the sun's diminishing.

Oh also, the sun is so massive and each planet's weight relationally insignificant that the sun could lose half its weight and we'd still be orbitting happily

so cheer up chum!