Main Methods Of Measuring Astronomical Distances

This problem wasn't solved until the 1920s, when Edwin Hubble devised the first method of extragalactic distance measurement. His technique relied on stars known as Cepheid variables, whose luminosities can be easily determined by measuring their rates of pulsation. Comparing this luminosity with the stars' observed brightness allowed Hubble to estimate the distance to Cepheid stars in such galaxies, affirming their extragalactic location.

It is easy to flip to the index of an astronomy textbook to discover that, say, the Sun lies 150 million kilometers away from Earth.  It is far more difficult (if not impossible), however, to picture this distance in the human mind.  In this exercise, we will learn to access the often unpalatable distances encountered in astronomy by simply scaling the huge distances to more recognizable, pedestrian numbers.  So long as every distance within the system of interest is scaled by the same factor, we retain the meaningful information about relative distances between objects.

A distance determination is the process of estimating the distance between where a shot is fired and its target. This is often done by looking at the patterns of powder

We can determine an object’s temperature from its thermal (or “blackbody”) spectrum by finding the wavelength at which it emits the most electromagnetic radiation.

A stars luminosity is measured by the apparent magnitude and absolute magnitude of the star and the amount of the light that is being emitting from it’s surface.

Nainoa Thompson created the star compass, as the basis for direction finding in non-instrument navigation. The horizon is divided into 32 sections called "houses." Nainoa has placed

It is easy to flip to the index of an astronomy textbook to discover that, say, the Sun lies 150 million kilometers away from Earth. It is far more difficult (if not impossible), however, to picture this distance in our mind. In this exercise, we will learn to access the often unpalatable distances encountered in astronomy by simply scaling the huge distances to more recognizable, familiar numbers. So long as every distance within the system of interest is scaled by the same

Some limitations are that parallax angles of less than 0.001 arcsec are very difficult to measure from Earth because of the effects on the Earth’s atmosphere. This limits Earth based telescopes to measuring the distances to stars about 10.01 or 100 parsecs away. Spaced based telescopes can get accuracy to 0.001, which has increased the number of stars whose distance could be measured with this method. However, most stars even in our own galaxy are much further away than 1000 parsecs, since the Milky Way is about 30,000 parsecs across.

An astrolabe is used by astronomers and navigators to measure the inclined position of a celestial body, to identify stars and planets, and to determine local latitude. Based on research, most attribute the invention of the earliest astrolabe to Hipparchus. The name even has its origins from the Greek words astron and lambanien meaning "the one who catches the heavenly bodies (Meech, 2000). Historically, astrolabes were intricately designed brass disks, and could serve multiple purposes. They could determine the position of celestial objects, measure the time of the night (or of the day, using it as a mobile sundial or, more accurately by measuring the altitude of the sun), measure the time of the year, compute what part of the sky is visible at any time, determine the altitude of any object over the horizon, and determine the current latitude (Meech,

By looking at the different wavelengths or the spectrum of light from a celestial object, you can tell many of its properties and features. To do this, the Hubble Telescope is equipped with various scientific instruments. Each instrument used

of other planets such as Saturn or Mars are a great way of studying other planets surfaces

The first thing I wanted to do was to estimate the approximate distance of which the

The radial velocity method was used to detect the first exoplanet, 51 Pegasi b (51 Peg b) around a main sequence star, 51 Pegasi (51 Peg). The radial velocity method uses the variations in velocity of a star due to the gravitational pull from an exoplanet (Lissauer 2002). Furthermore the velocity isn’t measured in terms of actual speed but in terms of light based on the Doppler effect. The Doppler effect occurs when a star moves. When it moves toward us, its wavelengths of light are shortened and when a star moves away from us, its wavelengths of light are lengthened. Through the continued observation of the Doppler effect on a stars spectrum of light, the velocity of a star is inferred. Any change in a stars velocity is caused by a sufficiently massive companion, an exoplanet (Lissaeur 2002).

Some of the scientific data that follows was taken out of Cattermole's book. The mean distance from the sun is 108.20 Km.

Once microwave radiation was discovered, studies improved on the Milky Way Galaxy. Its Doppler Shift can be used to map the motion of gas in it. Also, with radio telescopes, hydrogen gas can now be traced. When the Hubble Space Telescope was introduced in 1990, that made exploring space so much easier and more efficient. That’s how we discovered so much about our universe- including galaxies!