First Dark Matter Galaxy Discovery
On February 23rd, 2005, British astronomers discovered an invisible dark galaxy. The mass rotates like a galaxy but has no light, which means that there were no stars. It was found with a radio telescope at the University of Manchester.
Why is it important? Lets Ask Louis Strigari of UC Irvine:
Researchers on Dark Matter and Their Effects Today
Fritz Zwicky was an astronomer to conclude dark matter existed and proposed the idea in 1933. He applied Newton's laws and measured the speeds of galaxies with clusters to make out the mass of the clusters. He also used the amount of visible matter in the clusters by measuring their brightness. The two measurements present that giant clusters consist of about ten time more invisible matter than the visible.
His conclusions were neglected for a few decades until two astronomers Vera S. Rubin and W. Kent Ford, Jr. of the Carnegie Institution of Washington D.C. mapped the stars' motions in galaxies near the Milky Way. They had reached the same conclusion Zwicky did, where each galaxy includes enormous amounts of dark matter and is far more abundant than luminous materials in the galaxy's stars. Its greater components create a large, dark halo spreay way beyond the stars we can see.
Today's astronomers apply Zwicky's logic to detect vast amounts of galaxies far, far away. They observe other things in space like clouds of hot gas and discover things like "gravitational lensing."
lensing_jpg_83751.jpg --> GRAVITATIONAL LENSING
How do we know it exists?
We do not know it exists, but we strongly believe it does because it is believed that dark matter generates gravity; and if dark matter didn't exsist, the Universe would collapse.
When you look at the night sky, you see many glowing things like stars, planets, and galaxies. Protons, neutrons, and electrons that make up everything we can see. So through a telescope we’ve only taken note of 4 percent of energy of the Universe, the rest is dark and mysterious.
It is hard for scientist to observe and learn about the dark Universe, because we cannot directly see any of it. They can only witness the effects of these strange substances have on the material around it through gravity. Luckily, scientist developed a telescope like Chandra to explore the dark realm. Scientist have known about dark matter for decades, but still struggle to figure out what it is. We only know very few about it, when dark matter comes to gravity it acts like regular matter. Unlike normal matter, dark matter emits no light; therefore, we can conclude that it is very different from the elements found in stars and planet. To learn more about dark matter is to study clusters of galaxies, in fact galaxy clusters have the first evidence of dark matter in 1930s. The galaxies in galaxy clusters are moving around so quickly that there has to be a a lot of extra matter in clusters to hold them together with their gravity.
However, most of the normal matter is galaxy clusters is hot gas that can only be seen with an x-ray telescope like Chandra. There is still not enough mass in this hot gas to hold all the normal matter together, so astronomers came up with dark matter.
In the early 1990's, scientists were certain about the Universe is expanding. It might have enough energy density to stop its expansion and recollapse, it might have so little energy density that it would never stop expanding, but gravity was certain to slow the expansion as time pass by. The slowing had not been observed, but, theoretically, the expansion of the Universe had to be slow. The Universe is full of matter and the attractive force of gravity pulls all matter together. Then came 1998 and the Hubble Space Telescope observations of distant supernovae that showed that, a long time ago, the Universe was actually expanding more slowly than it is today. So the expansion of the Universe has not been slowing due to gravity, as everyone thought, it has been accelerating. No one expected this, no one knew how to explain it. But something was pushing the Universe apart.
Eventually theorists came up with explanations. Maybe there were some strange energy-fluid that filled space. Maybe there is something wrong with Einstein's theory of gravity and a new theory could include some kind of field that creates this cosmic acceleration. Theorists still don't know what the correct explanation is, but they have given the solution a name. It is called dark energy.
Dark energy is a mystery to us even though we know its effects and the fact that it takes up roughly 70% of our Universe. You are not going to believe this, but dark energy is a property of space also, and it expands our universe very slowly. Yes, the Universe is getting bigger as time goes by. There's has to be an explanation for this, right? No. There is only many possible explanations for the expansion of the Universe. For example, Albert Einstein and his Theory of General Relativity (the version with the cosmological constant) tried to explain that this "empty space," or dark energy, has its own energy. This pretty much makes it a property of itself, so it won't weaken as the Universe expands; and as the increasing expansion goes, the more energy would appear.However, no one has a clear vision of this possible explanation of why the cosmological constant is there, so it's intents and purposes are deemed unworthy.
There are other possible explanations like how space receives energy from the quantum theory of matter, dark energy being a new kind of fluid or field, and Einstein's theory of gravity is incorrect, but all had one constant: the mystery continued. And the only thing to solve it with is more data and accurate data.
image_preview--> THE UNIVERSE EXPANDING
CERN Accelerator Complex
To recreate the experience and to understand the Big Bang, CERN has created the accelerator complex. The accelerator complex is a series of machines accelerating particle in boosted energies. In each of these machines, a beam of particles is boosted before going into the next machine. The Large Hadron Collider-- the last machine of the acceleratorcomplex--has beams accelerated up to 4 TeV. The other parts have their own compartment where the beams are used for experiments in lower energies.
A bottle of hydrogen gas is the accelerator complex's proton source so that an electriv field is used to strip hydrogen atoms of their electrons to produce protons. The first machine in the accelerator is LInac 2, and it accelerates the protons to energies up to 50 MeV. The beam comes from it is injected into the Proton Synchotron Booster, where the protons accelerate higher at 1.4 GeV; it is then followed by the Proton Synchotron to push the beam to 25 GeV. The protons are sent to the Super Proton Synchotron to accelerate 450 GeV.
The protons are sent to two beam pipes in the LHC. In each pipes, the beams circulate in opposite directions from each other. They circulate for hours and hours under normal conditions and are brought to collision inside detectors--four to be exact (ALICE, ATLAS, CMS, AND LHCb)--where the collision point is equalt 8 TeV.
The accelerator complex includes other machines to provide for other projects, test areas, and facilities.
Protons are not the only particles running through the LHC, Lead ions are in there too. They come from vaproized lead and enter Linac 3 before being accumulated and accelerate into the Low Energy Ion Ring. Then, they follow the same path as protons at maximum energies.
If this all works out, we are able to obtain more data of dark matter and dark energy to figure out its mysteries. LHC_default.jpg --> DIAGRAM OF ACCELERATOR COMPLEX
- There is more dark matter in the universe than bright objects.
- Dark matter is of two kinds – the matter in galaxies (galactic), and the matter between them (intergalactic).
- Galactic dark matter can be the same as ordinary matter but has burnt out early in the universe’s life.
- Intergalactic dark matter is made up of WIMPs (Weakly Interacting Massive Particles).
- Some WIMPs are called cold dark matter because they are travelling slowly away from the Big Bang.
- Some WIMPs are called hot dark matter because they are travelling very fast away from the Big Bang.
- The future of the Universe depends on dark matter. If there is too much dark matter the universe may shrink.
- Dark matter may get trapped inside the sun and other stars effecting stellar energy transfer.