The Galaxy and Beyond

                 How did the universe begin? Why is it there? How did the sky fill with stars? What made the stars? How did the planets get here? Where does water come from? Where did life come from? And finally where did we come from? How did we get here? All this questions have been asked down the ages from Galileo, to Bruno, to Copernicus, to Aristotle, to early Romans to early Greeks, to early Egyptians, to Babylon, to Mesopotamia, to the upper Paleolithic, to the Stone Age, to before record the savanna’s in family groups following the other animals, their food source, as lions and cheetahs do today. In the last one hundred years but especially the last forty years with new and more advanced technologies in computers and stronger telescopes using a wide variety of different light waves including normal visuals light, and x-ray light to name a few. The knowledge of how the universe came to be as it is today is coming in faster than we can imagine. The laws of nature that apply in this galaxy that our star the sun and planet in the galaxy, three billion light years away from us or any of the five hundred billion other galaxies. But how did all the stars, planets, comets, asteroids and all the other galaxies get here in the first place? If there was once nothing anywhere, no life, no planets, no stars, no space and time, how did it all come from nothing? If you think about it, it sounds impossible for something as huge as all the matter in the universe to come from nothing, but nothing is where it came from. What caused the Big Bang? We don’t know and we may never know. But the Big Bang happened. If someone tells you that it didn’t happen that it’s only a theory, tell them, in science the word “theory” means “I dare anyone to prove it wrong”. We know that the Big Bang happened because all the galaxy groups are moving away from each other. If we could run the universe in reverse all the galaxies would collide with each other at a single point. Also the heat from the Big Bang is still detectible today, what is called the “Cosmic Microwave Background Radiation.” When the Big Bang happened it was not an explosion as say stick of dynamite would be. It was an explosion of space and with the beginning of space, the beginning of time. Time in our universe began between 13.7 and 15 billion years ago. The explosion of space caused a tremendous amount of heat from the burst of radiation at the moment of the Big Bang and this heat created electrons, protons, neutrons photons and neutrinos.

            Seven hundred thousand years later, the heat from the Big Bang cooled to a temperature that forced the electrons protons and neutrons to combine with each other, and when they did they made hydrogen atoms. The expending universe was filled with huge amounts of hydrogen atoms. Gravity took over and began to separate the hydrogen into different groups of about two hundred billion separate the hydrogen atoms, each thousand light years. A  Beam of light travels six trillion miles (one light year is a measure of distance equal to six trillion miles). These groups of atoms began to rotate around the center of these galaxies made of hydrogen atoms. As the atoms rotated around the center, they began to become larger and larger as gravity pulls in more atoms. The more atoms that stick together the larger they get and the more gravity these balls of hydrogen atoms have to pull in more atoms. Also when two hydrogen atoms combine it makes one photon of light. And the star shines. Our star turns four hundred tons of hydrogen atoms into helium every second. There was how for the first time light in the universe. But while astronomers know that this period was over by about the time the universe was one billion years old, they know exactly when it began? To help answer this questions a team of astronomers got help from Masami Ouchy of the Carnegie Observatories to find some of the early, extremely distanced galaxies. They look for dropout galaxies, and use progressively redder filters that reveal increasing wave lengths of light and watch which galaxies disappear from or? Drop out? Of images made by using those filters. The specific wavelengths of light at which the “dropout” galaxies appear can tell astronomers their distance and age.

The most powerful telescope in Hawaii found the most distant galaxy ever seen, located 12.88 billion years after the Big Bang. Observing objects this distant is extremely difficult, not only because much of the universe was obscured behind neutral hydrogen. Stars only then began clearing out this neutral hydrogen, making the universe transparent. Their most recent discovery is of a galaxy called Iok-1 that lies so far away that astronomers are seeing it as it appeared 12.88 billion years ago. This discovery indicates that galaxies existed only 780 million years after the universe came into existence about 13.66 billion years ago as a hot6 soup of elementary particles. They found that Iok-1 the brighter of the two has a redshift of 6.964. Confirming its 12.88 billion light year distance

The sun is one of the stars of around 100 billion that make up Milky Way, a large Spiral Galaxy that started to form around 12.5 billion years ago. AT the very center of the Milky Way lies a black hole with a mass of about 3 million solar masses. This core or nucleus of the galaxy is surrounded by an infinite number of stars that grow denser and closer to the center. This forms an ellipsoid of about fifteen hundred light- years. The longest dimension lying on the plane is the disk containing most of the galaxies stellar materials. Young stars make out a spiral pattern, and it is thought that they radiate out from a bar. Surrounding the bulge and disk is a halo in which lie some 200 globular clusters. The Milky Way would look like a huge Catherine wheel, with the majority of its light coming from the arms spiraling out from the central bulge. The materials in the spiral arms are slightly denser than matter in the rest of the disk. Two mechanisms are thought to create the Milky Way’s spiral structure.

Is the Milky Way active? The Milky Way galaxy, like any other galaxy with a central black hole, has the potential to be active. There is evidence that it might have burst into activity in the recent past. In 1997, scientist discovered a huge cloud of gamma-ray emission above the galactic center. They suggest that it’s the result of electrons encountering positions, and annihilating a burst of energy. Since the clouds lie just 3,000 light-years from the galactic center, the activity must have accrued recently. Why is the Milky Way’s black hole so quiescent? Well the black hole known as saggitarius A, is a certified monster, containing about 4 million times the mass of our sun. The energy radiated from its surroundings is billions of times weaker than the radiation from central black holes in other galaxies. They have realized that the black hole was far more active in the past. Maybe it’s just resting after a major outburst. When gas spirals toward the center of the black hole, it heats up to millions of degrees and emits x-rays. When x-rays reach the cloud, they collide with iron atoms, kicking out electrons that are close to the atomic nucleus. By astronomers observing how this cloud lit up and faded over 10 years ago, they could trace back the black hole’s activity 300 years ago.

Another most famous galaxy other than the Milky Way has to be the M31 in Andromeda, the “Great Spiral Nebula in Andromeda” is probably the best known for a couple of reasons. First it’s apparently very similar to our own Milky Way, so we can look at M31 and say “that’s what our galaxy looks like. Second, it’s going to collide with the Milky Way in about four billion years or so. That’s kind of special right there.

The evolution of clusters can tell astronomers about dark matter, and clusters can even be used as cosmic lenses, to peer back in to early universe the smallest types of clusters are usually termed “groups”. A local group, of which the Milky Way is a member, is one such cluster. Another type of cluster as the nearby Vigo cluster is denser, and it contains many hundreds of galaxies. Yet other clusters like the Coma Cluster are even denser and are dominated by giant elliptical galaxies. Not all galaxies exist in clusters, they are more insolated then there are cluster galaxies. Giant elliptical always lie near the center of large clusters.

X-ray satellites such as Chandra have revealed the nature of part of this material, large galaxy clusters often contain huge clouds of sparse, hot gas, glowing at x-ray wave lengths. Most of it is hydrogen, but has heavier elements. Most of a clusters mass is not gas, however dark matter.




Trough out the universe, galaxies exist in enormous diversity. The smallest galaxies only contain a few million stars; the largest is a couple trillion. Some galaxies are only that size. Some contain only old red and yellow stars, while others are blazing star factories, full of young blue and white stars, gas, and dust. Galaxies can be classified by their shape and color. Some 25-30 percent of galaxies in the nearby universe are spirals. The brightest clusters of young blue and white stars are found only in the spiral arms. Once every few hundred million years Spiral galaxies rotate slowly. Stars orbiting farther away take longer to complete on orbit than those close to the core. The “differential rotation” is the key to understanding the spiral arms.

Lenticular galaxies appear to be relatives of elliptical. They are dominated by a spherical nucleus of old red and yellow stars. However around this nucleus, these galaxies also have a disk of stars and gas. This links them to spiral galaxies, and they are similar in size and general shape. The overall shape is often described as that of a lens, which is the root of the name “lenticular”. The key difference between lenticulars and spirals is that lenticulars have no spiral arms and little sign of star forming in their disks. Without the blue star clusters that illuminate the disks of spirals, lenticulars are sometimes hard to tell apart from elliptical. Astronomers are not sure how lenticular galaxies form, but have lost most of their dust and gas.

An elliptical galaxy is a galaxy having an approximately ellipsoidal shape and a smooth nearly brightness profile. They range in shape to highly flat and size from hundreds of millions to over trillion stars. They can be the result of two galaxies colliding. Elliptical galaxies are also called “early-type” galaxies due to their location in the Hubble sequence. They are surrounded by large numbers of globular clusters Elliptical galaxies are believed to make up approximately 10-15% of galaxies in the local universe. They are found close to the centers of galaxy clusters, and are less common in the early universe.

An irregular galaxy is a galaxy that does not have a distinct regular shape, like a spiral or an elliptical galaxy. The shape of an irregular galaxy is uncommon, and do not fall into any of the regular classes of the Hubble sequence this type of galaxy does not have nuclear budge nor any trace of spiral arm structure. They are thought make up about a quarter of all the galaxies. Most irregular galaxies were once spiral or elliptical galaxies, but were deformed by disorders and gravity pull. They also contain abundant amounts of gas and dust. There are two major Hubble types of irregular galaxies An Irr-I galaxy is an irregular galaxy that features some structure but not enough to place it cleanly into the Hubble sequence.

Why is the Milky Way’s black hole so quiescent? The black hole known as Sagittarius A is a certified monster, containing about 4 million times the mass of or sun. The energy radiated from its surroundings is billions of times weaker than the radiation from central black holes in other galaxies. They have realized that the black was more active in the past. Maybe it’s just resting from a major outburst. When gas spirals toward the center of the black hole, it heats up to millions of dredgers and emits x-rays. When x-rays reach the cloud, they collide with iron atoms, kicking out electrons that are close to the atomic nucleus. By astronomers observing how this cloud lit up and faded over 10 years ago, they could trace back the black hole’s activity 300 years ago. 

For over 200 hundred years, the burning of fossil fuels, such as coal and oil, and deforestation has caused the concentrations of heat trapping to increase significantly in our atmosphere. These gases prevent heat from escaping to space, somewhat like the glass panels of a greenhouse. Greenhouse is necessary for life, because they keep the planet surface warmer than it otherwise would be. Climate affects people, plants, and animals. Scientist are working to better understand future effects on earth. But if these gasses continue to increase in the atmosphere, the Earth’s temperature is passing above past levels. According to scientist the earth’s temperature increased by about 1.2 to 1.2of in the past 100 years, the warmest it got in was in 2005. Climate models predict that the average temperature at the Earth’s surface could increase from 3.2 to 7.2 above 2005 levels by the end of this century.                  

We can prevent global warming by cleaning up the streets. Keep in mind paper, plastic, news paper, glass and aluminum cans can be recycled. By recycling half of household waste, we can save 2,400 pounds of carbon dioxide annually. All light bulbs that are CFL save a percentage of 70% than a regular light bulb. Instead of buying a car that’s going to use gas or diesel replace it with a hybrid car which converts more distance than fuel. Unplug any electric devises that you know are going to waste electricity. These are a couple of ideas on how we can save our world from global warming. Drive less, take bikes walk or carpool whenever possible. Clean or replace your filters monthly. Choose energy-efficient appliances when it’s time to buy new ones. You can always decrease your air travel. A really good idea is to plant a tree to help our earth breathe a little more.       

The first egoist names Harrison Schmitt was the first person to ever walk on the moon. He was one of the highlights of the Apollo mission because he was also the first person to find the orange glass on the moon. This smart astronaut is somebody I look up to because one day I want to accomplish my dream of going stepping on the one day, and explore the galaxies. This is going to make feel like I’m on top of the, and can actually acomplish it.