When you think about it, the most likely candidate to host life on earth is a planet like the Earth or one very similar in both mass and composition to the Earth. The Sun, the largest star, is only one of thousands of billion stars whizzing around in a vast cosmic space known as the Milky Way Galaxy. Even if scientists were to find evidence of life on a very similar planet like the Earth, it is most likely that the existence of life on such a planet would be extremely short-lived. The reason for this is that planets with life must have a specific temperature and atmospheric makeup to be hospitable to life. While it is possible to learn enough about the composition of a terrestrial planet to study its potential for supporting life, it is much more difficult to study another planet at the same time in the solar system from which it was formed. This is one reason why astronomers rely so heavily on the twin Gemini telescope in Hawaii and on the European Space Agency’s Very Large Telescope in Italy.
Astronomy books commonly tell us that “the galaxy is made up of three hundred million stars”, a figure which has come to be widely accepted by the scientific community as being an accurate estimation of the number of habitable planets that can be hosted by a solar system at the present time. Two of the major components of the Milky Way, and indeed all of the major components of the Milky Way, are in what is known as an “interstellar medium”. Although most astronomers refer to these mediums as ” Galactic Clouds” they actually comprise clouds of gas which are very hot, like the sun. They are also very dense and can be very cold, like the centers of the Mauna Survey on the island of Hawaii. The third component of the Milky Way is the “asteroidal galaxy” – a rotating disk of gas which contains many small moons which orbit around it. As described by Einstein’s theory of relativity, these small moons act like miniature satellites, and their presence in the intergalactic medium causes slight perturbations which cause the motion of the gas clouds.
So far we have established that the majority of galaxies are made up of elliptical disks. A few are “galactic clouds” while others are comprised of spiral arms which are more like barbells or marbles. There are also a few “icyclic” galaxies, some with massive black holes at their centres which act as nuclei for super clouds of gas, dust and stars to form and mature.