How Do Scientists Estimate the Distance to Stars?

[zli034]

Think about this, a photon travel through the universe, its path can be reflected by other objects, bended by gravity. Therefore the path would not be a straight line anymore. But very often from the TV science shows stating the distances to other stars are some some million light years.

How did they get the distance in light years? Are we able to measure the distance to the stars?

 

[NobodySpecial]

For pretty much all the stars we see the light came more or less straight to us.

The distance to stars is a fascinating subject.

The nearest stars we can measure the distance to directly by something called parallax.
Hold out you finger and close each eye in turn, you see the finger move compared to distance obejcts. Now if you know the distance between your eyes and the angle the finger seemed to move against the background you can measure the length of your arm.
If you measure the position of a star (very accurately) 6months apart - so the Earth has moved from one side of the sun to the other. then you can measure the distance to the nearest 10,000 or so stars very accurately.

Beyond that it gets a bit less exact. We might see a nearby star that we know the distance to and be able to measure it's temperature and chemistry, we then see a fainter star with the same signature we can guess that it's the same absolute brightness and so from how much fainter it seems to us we can estimate how much further away it must be

 

[mathman]

Try google "measure distance to stars". It is complicated in that nearby stars are measured by parrallax while further away stars and galaxies use various other measures depending on distance.

 

[Kracatoan]

http://en.wikipedia.org/wiki/Cosmic_distance_ladder might be of use.

 

[pmacias]

I can say that estimating the distance to stars is a complex and ongoing process. While it is true that the path of a photon can be affected by other objects and gravity, scientists have developed sophisticated methods to account for these factors and accurately measure the distance to stars.

One common method used is called parallax, which involves measuring the apparent shift of a star's position when viewed from different locations on Earth. By using this method and a baseline distance of the Earth's orbit around the sun, scientists can calculate the distance to nearby stars.

For more distant stars, scientists use a variety of techniques such as spectroscopy and standard candles to estimate their distance. These methods rely on measuring the properties of the star, such as its brightness and spectrum, and comparing them to known standards.

It is also important to note that the distances to stars stated in TV science shows are often rounded and simplified for the general public. The actual distances may be more precise and may also vary depending on the method used to measure them.

In short, while estimating the distance to stars is a complex and ongoing process, scientists have developed reliable methods to measure these vast distances and continue to refine and improve them.