How do scientists calculate the distance between our Earth and some other star or Galaxy?

Like the other guy said, Cepheid variables and supernova Ia are useful. Also, look up the Doppler effect - the more something is moving, the larger a shift we see in it's spectra, and since we know the rate at which the universe is expanding, we can use that to calculate how far away it is from us.

For very close by objects, we can use stellar parallax as well.

Hi. They use parallax for the nearer stars using the Earth's position at six month intervals to triangulate the distance. Farther objects use 'Standard candles' to compare the brightness of an object to known distances to nearer objects. The brightness of type 1A supernovas is both consistent and known and by studying these astronomers can calculate distances more or less accurately. This may break down at huge distances (my opinion) and then we invent such things as the 'cosmological constant' and dark matter and energy. Not proven nor does it make a lot of sense. But they agree in principle that most nearer measurements are pretty accurate.

I agree with Eri.

Galaxies are far too distant to use parallax for ranging. Cepheid variables only work out to a limited distance as well. The only method available for ranging distant galaxies is to use redshift - or specifically the shifting of Hydrogen absortion (Balmer) lines in the spectra...

Darnit Gary Seven - you beat me again... By the way - I loved your character in Assignment Earth!! :)

For measuring the distance to stars a technique called "parallax" is most often used. This website to find out how the technique works =>http://www.astronomy.ohio-state.edu/~pogge/Ast162/...

To find the distance to relatively nearby galaxies a special type of star known as a Cepheid variable is used. (http://apod.gsfc.nasa.gov/apod/lib/glossary.html) For galaxies at extreme ranges the redshift technique is used.(http://www.talkorigins.org/faqs/astronomy/distance...

Lots of different ways... Cepheid variables, parallax, triangulation... Google all that =)

Trigonometric measures

one of the process is trianglulation.