How do scientists figure out how heavy the sun is?

Question

please let me know

Answer 1

Well, to understand that, you need to know that the sun is made up of:
Hydrogen - 70%
Helium - 28%
Carbon, Nitrogen, Oxygen - 1.5%
other elements - 0.5%

They know the percentage and they know the atomic masses for each element, so it's basically a matter of "Each atom of X weighs Y and there are aproximately Z atoms of X in the sun". It's basic chemistry on a monumental scale

Answer 2

You've asked about one of the fundamental issues in astronomy, namely determining the mass of objects such as the Sun and other stars. The short answer is that there is no other way to *directly* measure the mass of the Sun or any other star than by observing the gravitational effects of one object on another.

You can estimate the mass of the Sun one of two ways. Both use Newton's Laws of motion. The first way uses Newton's revision of Kepler's third law, which states that the period squared or any body orbiting the Sun is proportional to its average distance from the Sun cubed. Newton generalized this for all gravitating systems. In the case of the Sun, the equation we can use is:

Mass_of_Sun=((4*pi2)/G) (a3/P2), where pi=3.14159, G is a fundamental constant, a is the radius of the Earth's orbit about the Sun, and P is the orbital period of the Earth about the Sun.

Another method uses Newton's second law and gravitation. In this case, one starts with F=m*a (where F is the force on an object, m is the mass of the object and a is the acceleration of the object due to the force). Since the gravitational force can be expressed as

F = G(MSun)(Mearth)/(R2)

where MSun and Mearth are the masses of the Sun and Earth, and R is the distance between the two, and the acceleration for a circular orbit is equal to the velocity2/R, Newton's second law can be rewritten in this case to give

Mass_of_Sun=velocity2*R/G

In both cases, putting in the values for Earth's orbital velocity, distance from Sun and the value for G gives a value of about 2 x 1030 kg for the mass of the Sun. (That's 2 with 30 zeroes after it.)

Answer 3

Well, keep in mind, "heavy" implies weight, which is anthropocentric arbitraryness. We created weight to measure how much the gravity of earth pulls on things.

The sun itself is large enough that it has it's own, much larger force of gravity, holding the earth in orbit.

Technically we'd probably want to look at its mass. But to get right to the technical nitty gritty;

The mass of the Sun is easy to determine using Newton's form for Kepler's Third Law of Planetary Motion, i.e.,

P**2 = 4 x pi**2 x a**3 / G / (Mass of the Sun + Mass of the Planet)

Here, P is the orbital period of the planet, pi = 3.14, a is the semi-major axis of the planet's orbit and G is the gravitational constant. (The value for G depends upon the unit system one chooses to work in.) Using the Earth and noting that the Earth is only 1/330,000 of the mass of the Sun, we determine the mass of the Sun from

Mass of the Sun = 4 x pi**2 x (A.U.)**3 / (G x P**2)

To calculate the mass of the Sun we choose to work in c.g.s. units so that 1 A.U. = 1,490,000,000,000 cm, P = 31,000,000 seconds, pi = 3.14, and G = 0.0000000667. We find that the mass of the Sun is roughly 1.99 x 10**33 grams. Note that in centimeters-grams-seconds (c.g.s.), all lengths are measured in cm, all masses are measured in gm, and the time is measured in seconds. There are other unit-conventions, for example, meters-kilograms-seconds (m.k.s.) in which I measure lengths in meters, masses in kilograms, and time in seconds. It doesn't matter which unit system you choose as long as you are consistent.

The method used to determine the masses of stars is precisely the same method (or a variant of the method) used to determine the mass of the Sun. (Except that one uses double star systems rather than planetary systems.)

Answer 4

They calculate it from how long Earth and other planets and comets and asteroids take to orbit it. Gravity and distance control how fast an object has to move to stay in orbit. We can measure the distance to the Sun and then calculate how heavy it must be for the Earth to be orbiting once a year.

Answer 5

By watching its gravitational effects and comparing it with others. There is something scientists use called an H/R diagram - a sort of comparison chart which goes into more detail & includes luminosity and temperature of stars.

http://en.wikipedia.org/wiki/Hertzsprung-Russell_diagram

Answer 6

Math. They know how big the sun is and the density of the gasses that make up the sun and they can calculate weight based on mass and density.

Answer 7

They know our distance from the sun, and what our orbital period is. Our orbital speed depends on how massive the sun is; if the sun were heavier, then we'd orbit faster. If the sun were lighter, we'd orbit slower.

Answer 8

You hold a cow in one hand and the Sun in the other hand.
The heaviest one will be the one that sags to the ground first.

Answer 9

the sun is made up of elements, so they should just weigh the elements.

Answer 10

Maybe by its gravitational field