# Sun mass loss

## Main Question or Discussion Point

From nuclear theory and texts its known that every second 570 millions tons of hydrogen are converted to 566 millton hellium,hence Sun loss 4 mill tons of mass in a second. But ¿how do astrophicisist probe experimentally this number?,have they measured solar gravity field or Earth atraction variation during the years,for example? Are the instruments enough sensitive to detect this

JPAM

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Astronuc
Staff Emeritus
Is that metric or short tons? There's a difference.

That is probably based on Luminosity of the sun - or power radiated. There are also occasional coronal mass ejections (CME's) in which a large mass is blown off the sun.

Let's assume metric tons - so the sun looses 4 MT/sec or 4 Gkg/s ( 4 billion kg/s)

Putting that into perspective - the sun mass is approximately 2 x 1030 kg, so the sun looses (4 E9)/(2 E 30) or 2 E-21 of it's mass per sec.

In one year, or ~3.156 E 7 seconds, the sun would lose 6.31 E-14 of it's mass, and in 5 billion years, the sun would lose only, 0.0003156 of it mass, excluding CME's.

ref: http://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html

http://csep10.phys.utk.edu/astr162/lect/sun/basics.html

mgb_phys
Homework Helper
4M T/s is about what you get if you use the energy output 3.8E26 J/s and E=mc^2.
The mass loss due to solar wind and gas ejection is much higher than this

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Do you have the data about how much is bigger the mass loss by solar wind than for nuclear reactions?
Regarding my first post, i guess that astronomers made theoretical models and then calculated 4 million tons/sec of mass converted in energy, but my question is that this number can be or has been probed experimentally,measureing for example a very small diminishing in gravitational atraction of the Sun on the Earth or a satellite ,for a timelapse of various decades

nobody has done this. Instruments will probably never be sensitive enough but there is not much point anyway, its a reasonably well understood process, the reactions are simulated with particle accelerators