How did they discover galaxies?

In 1923 Hubble was studying the Andromeda “Nebula” (now called the Andromeda Galaxy), when he realised that one of the objects he was observing was in fact a Cepheid variable star. This finally ended the debate on the nature of the spiral nebulae – they were indeed distant galaxies like our Milky Way.

How did scientists discover other galaxies?

It was only when Hubble measured the distance to the Andromeda galaxy using cepheid variables with the giant 2.5-meter reflector on Mount Wilson in 1924 that the existence of other galaxies similar to the Milky Way in size and content was established.

How did Edwin Hubble discover galaxies?

Edwin Hubble observed stars in a hazy patch of light that at the time was known as the Andromeda nebula. Specifically, Hubble observed variable stars, those that change in brightness. Thanks to Hubble, we know it today as the Andromeda galaxy. It is the nearest large spiral galaxy beyond the Milky Way.

Who discovered the motion of galaxies?

By plotting the distance of eighteen galaxies against their red shifts, Hubble discovered a direct relationship: Galaxies were moving away from earth at a rate proportional to their distance from us. Hubble’s discovery was not just unexpected, but monumental.

How did Edwin Hubble discovered that galaxies are moving away from us?

By plotting the distance of eighteen galaxies against their red shifts, Hubble discovered a direct relationship: Galaxies were moving away from earth at a rate proportional to their distance from us. In other words, the greater the distance between a galaxy and the earth, the faster that galaxy was moving away from us.

How many galaxies have scientists discovered?

The Hubble Deep Field, an extremely long exposure of a relatively empty part of the sky, provided evidence that there are about 125 billion (1.25×1011) galaxies in the observable universe.

How was the Milky Way galaxy discovered?

Galileo was the first to see the Milky Way Galaxy in 1610 as individual stars through the telescope.

Who discovered the first galaxies?

Other galaxies had been discovered, but they were thought to be smaller objects within our galaxy. The first galaxies were identified in the 17th Century by the French astronomer Charles Messier, although at the time he did not know what they were.

What is the classification of a satellite galaxy?

Classification of satellite galaxies. As mentioned above, satellite galaxies are generally categorized as dwarf galaxies and therefore follow a similar Hubble classification scheme as their host with the minor addition of a lowercase “d” in front of the various standard types to designate the dwarf galaxy status.

What is a dwarf irregular satellite galaxy?

Dwarf irregular satellite galaxies are characterized by their chaotic and asymmetric appearance, low gas fractions, high star formation rate and low metallicity. Three of the closest dwarf irregular satellites of the Milky Way include the Small Magellanic Cloud, Canis Major Dwarf, and the newly discovered Antlia 2 .

How many satellite galaxies are there in the Milky Way?

In particular, the Milky Way is currently known to host 59 satellite galaxies (see satellite galaxies of the Milky Way ), however two of these satellites known as the Large Magellanic Cloud and Small Magellanic Cloud have been observable in the Southern Hemisphere with the unaided eye since ancient times.