how do you find the distance between earth and the celestial bodies?

Question

please explain it clearly

Answer 1

Stars are measured by parallax method. Basically it is trigonometry, but in its most refined state.

To understand parallax, hold a finger up about 8 inches in front of your eyes, and look at it with first one eye, then the other. Your finger will appear to jump. This is because your eyes are a couple inches apart and each is viewing the finger from a slightly different angle.

Now hold your finger at arms length and do the one eye at a time thing again. Your finger still jumps, but much less than before. Imagine someones finger held up on the other side of the street, then doing the one-eye thing you will not be able to see the finger move – but nevertheless, it does, but too small an amount for you to notice.

The fact is that if you measure that jump and you know the distance between your eyes, it is easy to calculate the distance to the finger using basic trig.

When Galileo and others after him had the use of telescopes, they realised that the planets were closer than the stars, but in order to really prove that the Solar System is not the centre of the universe they had to measure the stars. They knew the math to do the trig, and they had the sense to realise that they might need the whole width of the Earth’s orbit (186,000,000 miles or 300,000,000 kms) to effect a parallax shift in the stars (that is the equivalent of the gap between your eyes in the above example).

But as huge as the base of their measurements, (the six months it took between measurements from opposite sides of Earth’s orbit), it took until the 19th century before there were instruments capable of measuring the minute jump that some stars make when you compare their positions six months apart.

The nearest star, Alpha Centauri, changes position about 1/4000th of a degree when viewed from opposite sides of the Earth’s orbit. This equates to it being about quarter million times as far away as the sun.

That is the nearest star. Obviously, the measurements get even finer the further way the stars are. But now it is done with computers and CCD technology, and the latest push is to measure precisely the distance to 1 billion of the nearest stars.

But that is till only a tiny fraction of the stars in our galaxy.

Answer 2

There are 3 tried & true methods.... If a body is close enough to Earth (like the moon), the angle of a point on the moon when viewed at the same time from two different places on Earth will let you form an equilateral triangle, with two known angles that allows you to work the math to get the distance.

For nearby stars, Earth's orbit is 186 million miles in diameter, and the apparent position of a nearby star will 'shift' in comparison to background stars as Earth moves in it's orbit. (This is called Parallax.)

For objects outside the solar system, astronomers use red-shift; The faster the motion of an object away from Earth is, the more red-shifted it's light will be.

Answer 3

In a few words, the most basic method is measuring the angle between 2 positions of the celestial body and the Earth and using trig.

Answer 4

It has no longer some thing to do with the time it takes gentle to commute to earth. A popular astronomer called Edwin Hubble said a correlation between the gap a much off merchandise is way from us and the speed at which that's receding. that's undemanding as Hubble's regulation. We degree the speed at which that's receeding making use of what's undemanding as pink shift which has similarities in idea (actualy that's same) to the doplar outcome. have you ever said how the sound from a transferring automobile's engine is of a more beneficial pitch at the same time as that's drawing near you than at the same time as that's heading faraway from you? bear in options the funny tale a thanks to make a canines bypass meow? positioned it in the back of a automobile and stress up the street, meeeeeeooooooowwwwwww. it truly is undemanding because the doplar outcome, that's brought about by ability of the bunching up of sound waves because the article approaches you and stretching out of the sound waves because it leaves you, this similar outcome works with gentle, if an astronomical merchandise (like the Andromeda galaxy) is coming in the route of you the gentle is shifted in the route of the blue end of the spectrum because the gentle waves are bunched up, even if that's rushing faraway from us (like maximum galaxies) the gentle is shifted in the route of the pink end of the spectrum (spread out). Hubble's regulation provides us a relationship between the speed at which the galaxies are receeding and the gap they're. v = H0 D the position v is the speed the article is transferring faraway from us (determined by ability of pink shift) H0 is Hubble's consistent D = the gap the article is way from us. To get a more beneficial precise length for Hubble's consistent astronomers use usual candles - products of undemanding brightness so one can get an precise and solid distance so save refining Hubble's consistent so the outcomes are a turning out to be style of precise. 2 such usual candals are Cephid variables and style Ia supernovae desire this helps.

Answer 5

Depends on the body, the moon would need a different method that a remote star.

Answer 6

They are all moving so it changes all the time.

Answer 7

we can measure light and angles and determine distance