Missing Diagrams
You, the computer you’re sitting at, the air you breathe, even the distant stars are all made up of protons electrons and neutrons. For a long time this ordinary matter, or what physicists like to call baryonic matter, was thought to be the main constitute of the universe. However, in the past twenty years evidence has been accumulating to the contrary, that in fact the universe is much stranger than ever thought of before and is almost entirely made up of something that we can’t see.
For a long time astronomers weren’t concerned about the mass of objects that they couldn’t see. For example the earth is too small and dim to see from any great distance and all the planets in out solar system make up less than one percent of the total mass of the sun. However it soon became a concern when astronomers began to measure the mass of galactic clusters and it became apparent that there was a significant amount of matter unaccounted for.
In the thirties, astronomers named Zwicky and Smith both examined closely two relatively nearby clusters, the Coma cluster and the Virgo cluster. They looked at the individual galaxies making up the clusters individually, and the velocities of the clusters. What they found was that the velocities of the galaxies were about a factor of ten to one hundred larger than they expected.
In a cluster the main force is the gravitational pull of the galaxies on one another which gives rise to their velocities. By knowing the velocities of the galaxies the total mass of the cluster can be determined.
If your web browser is Java-aware -- e.g., Netscape 2.0b or higher, try this experiment. It allows you to vary the mass inside a galaxy cluster, and watch the individual galaxies.
Experiment I
( Courtesy of John's Homepage http://www.astro.queensu.ca/~dursi/dm-tutorial/dm1.html)
Now like all observations there is a certain amount of error involved. In this case, watching the galaxies in a cluster takes years of observation and the velocities are hard to determine due to the expanse of the cluster. It’s not like the experiment were the dots are whizzing around. Also some of the galaxies measured may not be in the cluster but are just in the line of site of the telescope.
Two men named Harlow Shapley and Heber Curtis has a debate in 1920 that is still important today for changing how we think about galaxies. They talked about five important things. The first thing they debated was how big our galaxy, the Milky Way, is. Shapley said that the Milky Way was much bigger than we first thought, 100,000 light-years across, and that, because it was that big, it had to be the only one. Curtis said the the Milky Way was smaller than that, and that other galaxies existed past ours. They were both right and both wrong. Shapley was right about the size of the Milky Way, and Curtis was right about there being many more galaxies in the universe.
In the first chapter we meet some of the characters and what they do. Both Daniela and Jason Dessen gave up their careers to start a family together. Jason goes to a party held for his former colleague, Ryan Holder, celebrating a Prize that he had earned. He and Jason talk and Jason gets enraged and leaves the party early. On his way home a kidnapper approaches him and forces him into a SUV. He takes Jason to an abandoned warehouse and injects a needle into his neck and slowly Jason goes unconscious.
Clusters like NGC 6530 were formed from the same cloud, and as a result have roughly the same age. This makes them of particular interest to astronomers. Because clusters are all formed from the same material, have roughly the same age, and distance from earth, variations in their brightness is only due to their mass ("Open Star Clusters"). This makes them particularly useful for studying stellar evolution. This cluster was first observed by Hodierna in 1654, and later found independently by Flamsteed in 1680 when he discovered the cluster was located within the Lagoon Nebula. Like most open star clusters, NGC 6530 is relatively young; having been formed less than 6 million years ago ("Young Stars Paint Spectacular Stellar Landscape"). It is known to consist of more than a hundred known bright stars, the light of which show very little reddening as a result of interstellar matter from the nebula, this is likely because the cluster is located just in front of the
This cluster located in Hercules consist of about 300,000 stars. It is more than “22,200 light years away, the brightest star in the cluster is call v11” (Constellation Guide, n.d.). The second objects that I find in the Hercules constellation is called NGC 6166. This object is classified as a supermassive type galaxy it’s an elliptical galaxy with a large number of stars. It is calculated that NGC 6166 consist of approximately 50 million stars, it is located about 490 million light years away, a galaxy that massive has a supermassive black hole at its core. The third objects is called Hercules A, it is an elliptical galaxy with plasma jets spanning over a million lights years around the galaxy. “It has a mass 1,000 times more than the milky way galaxy also at the center of Hercules A is its black hole which is more massive that the black hole at the center of the milky way” (Kerrod,
Despite all our advances in particle physics and astrophysics, we still don't know what form of matter makes up 95% of the universe. Physicists have named this mysterious substance dark matter, for it can not be detected by observation (it does not emit visible or other frequency light waves). However, we know that dark matter must exist, following Newton's universal law of gravity.
Every day we look into the night sky, wondering and dreaming what lies beyond our galaxy. Within our galaxy alone, there are millions upon millions of stars. This may be why it interests us to learn about all that we cannot see. Humans have known the existence of stars since they have had eyes, and see them as white glowing specks in the sky. The mystery lies beyond the white glowing specks we see but, in the things we cannot see in the night sky such as black holes.
An underlying theme present throughout the series is the possibility that our existence is not the only one. According to current theories in physics, it is entirely possible that our universe is just one of many universes f...
Waller, William H. The Milky Way: An Insider's Guide. Princeton, N.J: Princeton UP, 2013. 42+. Print.
Comparing this galaxy’s size to are own Milky Way Galaxy, which is estimated to be around 8.5*1011 solar masses large, the Andromeda Galaxy is about 20% bigger then are own. Along with this we also know that both our own galaxy and this galaxy are on a collision course. It is estimated that in around 7.5 billion years that these two galaxies will merge together in a surely violent process. It is suspected that after this a large disc or elliptical galaxy will exist in the place of the once separate galaxies.
By 1936, astronomers had realized that the hazy balls they sometimes saw in their telescopes, which looked like stars obscured by gas, were actually galaxies (Hibbison).
...at different points in the past, this observation presents an interesting argument for panspermia. While this study does not provide conclusive evidence for presence of life in outer space, it does raise the possibility that our galaxy may be fool with bacterial spores.
Astronomers believe that most galaxies consist of a supermassive black hole at the center, which attracts all constituents of galaxies such as, dust, gases (mainly Hydrogen and Helium), atoms, stars, interstellar clouds and planets to the center by force of gravity, but are not sure whether all galaxies contain a black hole in the center. Galaxies keep moving in relative motion to one another and intermittently can come so close that the force of gravitational attraction between the galaxies may become strong enough to cause a change in the shape of the galaxies, while in exceptional cases, the galaxies may collide. If two galaxies collide, they may pass right through without any effect or may merge, forming strands of stars, extending beyond 100,000 light years in space (World Book Online Reference Centre, 2005). Hence, neighboring and often other colliding galaxies induce the sha...
Since the beginning of astronomy, astronomers had a unanimous goal: to see farther, better and in greater details.
The Sun, in turn, is moving in an undulating orbit around the centre of the MIlky Way at 800,000 km/h (ka-boom would be 15 TJ - about a 3.5 kiloton baby nuke), which in turn is moving with the Local Group towards the Virgo Cluster, which in turn...... and so on and so on.