Furtherest object in the universe discovered

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Marsoups
Posts: 1368
Joined: Fri Dec 28, 2001 3:57 pm


A dim galaxy is the most distant object yet found

http://www.newscientist.com/article/dn1 ... found.html

Image
The distant galaxy, called UDFy-38135539, appears as a faint smudge inside the red circle in this image snapped by the Hubble Space Telescope (Image: NASA/ESA/G Illingworth/UCO/Lick Observatory/UCSC/HUDF09 Team)

A faint glow first spotted by the Hubble Space Telescope belongs to a galaxy that is the most distant object yet found, new observations suggest. The galaxy helps provide a window into the primordial cosmos, when a thick fog gave way to the transparent universe we see today.

The Hubble Space Telescope's Wide Field Camera 3 picked up the object as a dim infrared blob in observations made in August and September 2009.

It was suspected to be a very distant galaxy because its light is strongly reddened or skewed towards longer wavelengths, as expected for light that has travelled for billions of years to reach Earth. The intervening expansion of the universe stretches light waves, pushing them to longer, redder wavelengths.

But astronomers initially could not rule out the possibility that the object might be intrinsically red and much closer to Earth, such as a brown dwarf star in our own galaxy. The Hubble camera is not equipped to measure the detailed light spectrum needed to distinguish between such possibilities.

Now, follow-up observations made with an 8.2-metre telescope at the European Southern Observatory in Chile suggest the object sits far outside the Milky Way. Its light appears to be more than 13.1 billion years old, making it the most distant object confirmed to date.
High redshift

A team led by Matt Lehnert of the Observatoire de Paris, France, used the telescope to stare at the object for 16 hours to measure its light spectrum. The peaks and troughs in the spectrum – which correspond to light that is emitted or absorbed – included a spike at a wavelength of 1.16 micrometres. The team says the peak is most likely created by the glow of hot hydrogen gas from a distant galaxy. The light originally had a wavelength of 0.122 micrometres but has been greatly stretched en route to Earth.

The amount of this stretch, measured by a quantity called redshift, is 8.55, suggesting the light has taken more than 13.1 billion years to reach us. We see the galaxy as it appeared less than 600 million years after the big bang occurred, some 13.7 billion years ago.

"We have confirmed that a galaxy spotted earlier using Hubble is the most remote object identified so far in the Universe," says Lehnert. The record for most distant object was previously held by a self-destructing starMovie Camera with a redshift of 8.2, suggesting the blast occurred when the universe was 630 million years old.

Tentative candidates at even higher redshifts than the newfound galaxy have been reported, but they have not been confirmed with light spectrum measurements. Until now, the farthest galaxyMovie Camera to be spectroscopically confirmed had a redshift of 6.96.
Primeval fog

The extreme distance of this new galaxy – dubbed UDFy-38135539 – provides hints about how a primeval fog was lifted to make the universe more transparent to light. Much of the starlight in the first few hundred million years of the universe's existence was quickly absorbed by hydrogen gas permeating the cosmos.

These hydrogen atoms were eventually split into their constituent protons and electrons – a process called reionisation – by sources of radiation whose identity is still debated, leading to the more transparent universe we see today.

UDFy-38135539 existed at a time when the fog was still in the process of lifting. But the fact that it is visible at all indicates that much of the hydrogen around it has already been reionised.

Lehnert and colleagues calculate that radiation from the galaxy itself is insufficient to do the job, so it must have had help, perhaps from a retinue of smaller galaxies around it that are too faint to see.

"It's very exciting that we have possible evidence for a galaxy at a record breaking redshift," says Avi Loeb of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. But Loeb, who is not a member of Lehnert's team, says that contributions from Earth's atmosphere could add some uncertainty to the galaxy's distance. "I wouldn't say it's a slam dunk," he says.

The team admits there is a chance that the spike in the spectrum is due to oxygen instead of hydrogen, which would give it a much lower redshift of 2.12. The jittering of Earth's atmosphere could cause light from oxygen, which produces a pair of spikes, to blur into a single peak that looks like the one produced by hydrogen. But the team calculated this blurring should only occur in about 0.1 per cent of observations, making it unlikely to be the case.
Marsoups
Posts: 1368
Joined: Fri Dec 28, 2001 3:57 pm


My thoughts... Why do astronomers always talk about 'dark matter'.

What's to say that there aren't any other clusters of galaxies beyond our vision ? What would we see if there was one for example exploding so somewhere far off ? A blue-shifted supercluster of matter ? Or would the light wavelengths be too completely weak to pick up with current instruments ???
Pete_Paranoid
Posts: 2332
Joined: Tue Jun 17, 2003 2:45 am


Awesome, thanks for posting!
ionized
Posts: 1474
Joined: Tue Sep 20, 2005 4:20 pm


Marsoups wrote :
My thoughts... Why do astronomers always talk about 'dark matter'.


Because without it or something similar, there should just be random stars flying apart. Something is causes galaxies to form and it's not matter... (apparently). There's not enough of it to have a gravitational effect.
rollyz
Posts: 3334
Joined: Wed May 01, 2002 6:58 pm


Isn't space suposed to be curved? Maybe that distant galaxy is actually our own galaxy but in a different time....?
Last edited by rollyz on Mon Oct 25, 2010 12:43 pm, edited 1 time in total.
Marsoups
Posts: 1368
Joined: Fri Dec 28, 2001 3:57 pm


I wrote out my question on yahoo answers, one lad came back with this reply :

You have a lot of different questions here, and it seems like you're pretty confused and getting mixed up. Let me see if I can clarify some things for you... :)

Dark matter has nothing to do with the expansion of the Universe. That is dark energy.

Dark matter is the mysterious, completely invisible, non-matter, that has gravitational force and keeps galaxies from flinging apart. Dark matter is only able to be detected at the scale of a galaxy - we have yet to pinpoint what it actually is.

Dark energy is the mysterious force that is pulling the actual space that makes up the Universe apart. It actually makes space get bigger, so that things are getting farther and farther apart from each other over time. However it is also INCREDIBLY weak. The gravitational forces that we feel are billions of times stronger. Dark energy is incredibly weak, however it is constant everywhere in all of space, which adds up across really big distances, so that things that are far apart are getting farther apart faster than things that are close together. Dark energy really only affects things that are as far apart as galaxies are - even galaxy clusters don't feel dark energy.

Now, the expansion of the Universe leads to something interesting - If there is enough space between two points, the space between them will be expanding faster than the speed of light. So no matter how much time you've got, light CAN NEVER make it from one side of the Universe to the other. No amount of technology can ever change that (unless we can make worm holes or something) - so we will NEVER be able to see things that are outside of our visible Universe.

The Universe is certainly a MUCH larger place than our visible Universe. We can tell by looking at perturbations in the cosmic microwave background radiation that the Universe is much too smooth to be small, and it the entire Universe is probably trillions of times larger (at least) than the visible Universe.

Another issue is that the space between us is expanding faster and faster, so over time the galaxies that we can see right now will actually be FARTHER away, so over millions and billions of years, a person on Earth will actually see fewer and fewer galaxies - not more and more.


Another answered :

Would we be able to see an exploding "big bang" further out than the furthest observed object ? No because the light would be heading away from us
I was wondering whether all this talk about 'dark matter' could be related to other 'super clusters' of mass that are not observable with our technology ? We don't know yet. Possibly
Would an object beyond the depths of what is being observed here, appear blue-shifted if it was heading towards us ? Or would that light not be visible at all due to the distance ? Not visible
What are the chances that we would pick up whether there was other stuff / superclusters beyond what we've seen at present ? The longer we wait the more we will see, so if we wait a billion years we will be able to see an extra billion light years

EDIT: Bill Dark Energy and Matter have not been identified yet so we cannot say exactly what they do, though what you say is probably right you cannot say it as fact. And you do have a point about the galaxies moving apart
ionized
Posts: 1474
Joined: Tue Sep 20, 2005 4:20 pm


After you've digested that, you might like to wrap your head around this one.

Studies by a team at UNSW :D have discovered that one of the universal constants, the Fine Structure Constant (or Alpha), is apparently changing across the universe. Alpha relates to how matter and light interact and also how atoms are held together. The discovery, if proved true, would mean a new model of physics as Einstein's Theory of Relativity states that the constant should be universal.


http://www.newscientist.com/article/dn19429-laws-of-physics-may-change-across-the-universe.html
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