How do you measure objects and distance in space?

Answer 1

Objects in space are normally distanced using parallax, a measurement technique that compares its angle above the horizon from two widely separated points, or (for greater distances) over a period of time as the Earth orbits the Sun.

Answer 2

Parallax is a common method used to measure the distance to stars. Suppose you look at an object (like a tree or far away building), and measure the angle to it in reference to something known. Then you move a specific distance (say 100 meters), and take the same angle measurement. Then you can build a triangle and find the distance to the building using basic trigonometry. This is a common question for geometry and trig homework, with a boat and a lighthouse. When the object is farther away, you will see less change in angle for a given movement. For stars, we wait until the Earth has moved a sufficient known distance (say around to the other side of the sun).

For more distant stars and galaxies that are too far away for parallax t be used, we use the amount of the Red shift, which is created by the Doppler Effect to work out how fast an object is moving away from us.

When a space object is getting further away from us, the frequency of the light decreases, and absorption lines in the light are shifted toward the red end of the spectrum. Since the universe is expanding at a rate we believe we know, the amount of red shift allows us to calculate how fast the object is moving away from us and then to calculate how far from us it is.

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We can also use the strength of the gravitational lensing of an object if it is of a type that has a known brightness to work out its gravitational pull. Gravitational lensing is how much an object bends the light bends light passing near it from a more distant object. Once we know the gravity, we can work out how bright the object is supposed to shine (that happens because the stronger the gravity, the more frequently the fusion reactions will occur). Then we compare how bright an object shines to what it is supposed to. From here we know the distance.

For distances within our solar system we have used radar as well as parallax to determine distances. And when we have probes near distant locations we can also use the amount of time required for a message to reach the probe from us, or reach us from the probe, to determine its distance.

Answer 3

They use how dim the light is to determine how far away it is. Aside from that they use the light spectrum to determine if it is traveling toward us or away.

But the problem is that if you're looking at stars in the night sky, if a star is at a certain distance from you its brightness can't really be used as a measure of how far away it is because a bigger star will be brighter and because light gets dimmer the farther it is from you a big star can be a lot farther away than a small star and yet they'll both appear exactly the same brightness. How do you solve that one? This kept astronomers guessing for a very long time until about the turn of last century. A woman in contact with Hubble, after whom the Hubble Space Telescope is named, solved the problem. Her name was Henrietta Levitt and she was looking at star charts. She noticed that some star appeared to get bigger and brighter and then dimmer and weaker. They did it with a regular period. These have now become known as the stellar yardsticks. They're called Cepheid variables. They're stars that swell up and shrink down. Because the period at which they do that varies with the size of the star you therefore know, if you look at how often a star like that is blinking on and off, you know how big it is. Therefore you know how bright it is. Because light follows an inverse square law you can work backwards to work out how bright that star must be and therefore how far away it is. Scientists now use these Cepheid variables when they look at a distant star structure they can use the period of any Cepheid variables that are there to work out how far away those particular entities are. That's a stellar yardstick and it was solved by a lady at Harvard a hundred years ago.

Answer 4

By Radar, the same way a radar gun is used by the police. Bounce a pulse off the object get e measure of the distance. Bounce a second pulse off after a known time interval and get the new distance, then compute speed=(d2-d1)/ interval between pulses.

Answer 5

By using the habo space telescle to detect the

object's velocity

Answer 6

miles, kilometers, yards , feet