/sci/ - Science & Math

>>15797786
>Sun loses 4.7 million tons a second
>Gravitational energy between two masses is -GMm/r
>If I try to reduce the mass of the sun by 4.7 million tons per second and keep the mass of earth same,
>Then to keep the gravitational energy of the system same
>Earth would have to move away from the sun at the speed of 150 billion meters per second
>But earth is only moving away from the sun at 6 centimeters per year.
>There is something wrong. Probably in my calculation.

>>15797790

Thanks for fixing my reddit spacing.

>>15797790

I cannot ask this on reddit without getting banned so I ask here.

>>15797786
>Earth would have to move away from the sun at the speed of 150 billion meters per second
>500c
You fucked something up retard

>>15797804

solve for r in (1.989e30*5.9722e24/150e9) = ((1.989e30-4.7e9)*5.9722e24/r)

how else do you conserve energy in this case without moving away faster than light?

>>15797806
Not my problem

>>15797810

It is OK I solved for r here in the pic

As you can see earth has to move away from the sun faster than light to conserve energy

>>15797786
>>15797790
> The sun is something like a million times more massive than the Earth and loses an amount of mass equal to the mass of the Earth about every 100 million years.
Yeah, you fucked up.

>>15797814

The mass of the Sun is approximately 1.989 × 10^30 kg. This is equivalent to 333,000 times the mass of the Earth, or 2,000 times the mass of Jupiter.

The mass of the Earth is approximately 5.9722 × 10^24 kg.

The Sun loses about 4.7 million tons of mass every second. This is due to two main processes:

> Nuclear fusion
> Solar wind

>>15797813
Good job. We narrowed down your fuckup to somewhere earlier in the process

who says gravitational potential is conserved

>>15797826

Since conservation of energy is to be expected, where did the extra gravitational potential energy go when sun lost its mass through solar winds, and nuclear fusion?

>>15797837
i guess the mass it loses stays around the sun, you can't really destroy mass

>>15797813
run the calculation again, without minusing the mass per second lost by the sun

>>15797786
earth retains a some of the mass lost by the sun when the solar energy is converted back into mass via photosynthesis

>>15797813
The value for r you got is just that, r, not change in r. Find r_1 with no mass loss and r_2 with mass lost after 1 second, then the difference between the two is change in r per second. You'll find that change in r has the same order of magnitude as the difference in magnitudes between sun-mass and per-second-loss mass, or 10^9 / 1^30 = 10^-21. So in the ballpark 10^-21 meters per second.

>>15797813
Which number is bigger? 150x10^9 or 1.5x10^11?

>>15797813
150 x 10 ^ 9 = 1.5 x10^11.
there is no difference in radius between each calculation.

>>15797837
Into photons
>>15798047
Yes you can destroy mass. You convert it to energy

>>15797786
The earth sun system is not closed and gravitational potential is not conserved.

>>15797786