Image: Hubble sees spiral in Serpens

September 8, 2014, NASA
Credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt

(Phys.org) —This new NASA/ESA Hubble Space Telescope image shows a beautiful spiral galaxy known as PGC 54493, located in the constellation of Serpens (The Serpent). This galaxy is part of a galaxy cluster that has been studied by astronomers exploring an intriguing phenomenon known as weak gravitational lensing.

This effect, caused by the uneven distribution of matter (including ) throughout the Universe, has been explored via surveys such as the Hubble Medium Deep Survey. Dark matter is one of the great mysteries in cosmology. It behaves very differently from as it does not emit or absorb light or other forms of electromagnetic energy—hence the term "dark."

Even though we cannot observe dark matter directly, we know it exists. One prominent piece of evidence for the existence of this mysterious matter is known as the "galaxy rotation problem." Galaxies rotate at such speeds and in such a way that ordinary matter alone—the stuff we see—would not be able to hold them together. The amount of mass that is "missing" visibly is dark matter, which is thought to make up some 27 percent of the total contents of the Universe, with dark energy and normal matter making up the rest. PGC 55493 has been studied in connection with an effect known as cosmic shearing. This is a weak gravitational lensing effect that creates tiny distortions in images of distant galaxies.

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wsrmtls
1.8 / 5 (6) Sep 08, 2014
I was wandering if we or anyone sent a satalite into dark matter to see what it really is. If not why not do it.
antialias_physorg
4.3 / 5 (6) Sep 08, 2014
I was wandering if we or anyone sent a satalite into dark matter to see what it really is.

What sattelite-mountable instrument do you propose they use? Dark matter interacts very weakly (if at all). The experiments currently under way to detect it are rather large and need huge amounts of shielding to prevent false positives.
http://news.disco...1030.htm

If not why not do it.

http://arxiv.org/abs/1306.5534
Dark matter density constraints would indicate that the density within the solar system is fairly low. Places where density are higher are still somewhat out of our reach for shooting probes at.
cantdrive85
1.5 / 5 (8) Sep 08, 2014
I was wandering if we or anyone sent a satalite into dark matter to see what it really is. If not why not do it.


As soon as they figure out how to fix a satellite to a flying unicorn or leprechaun rocket such a whimsical notion would be possible.
ereeves
4 / 5 (1) Sep 08, 2014
"we know it exists"

Since "we cannot observe dark matter" and have never seen it with any experiment, exactly how do we "know" dark matter exists? I think better phasing might be "we believe the dark matter hypothesis must be correct".
Benni
1 / 5 (3) Sep 08, 2014
I was wandering if we or anyone sent a satalite into dark matter to see what it really is. If not why not do it.


First we'd need to locate a DM target point where the probability for DM is very high. This would not be an area in our solar system or any others nearby because we know by the gravity exerted by our sun & nearby stars that their gravity fields are accounted for by the mass of normal matter. The closest target area would be somewhere in a spiral arm of the Milky Way galaxy other than the one in which we are located, but we can't know for sure which one.

Next we need to get a rocket there. We don't have the rocket engines that could get a satellite to another spiral arm that could travel the distance inside any of our lifetimes, even if we did the rocket would not survive the trip because interstellar space has micron sized (& larger) dust particles traveling at speeds that will rip holes in the hull of the rocket rendering it a useless hulk upon arrival.

cantdrive85
1 / 5 (5) Sep 08, 2014
First we'd need to locate a DM target point where the probability for DM is very high.


Never Never Land? A galaxy far, far away? The end of the rainbow in the leprechaun"s pot? I know, between the ears of an astrophysicist because we know for a fact there is no gray matter there.
FineStructureConstant
5 / 5 (3) Sep 09, 2014
...between the ears of an astrophysicist because we know for a fact there is no gray matter there.
Whereas the heads of messianic proponents of whack-o pseudo-science are just crammed full of brains'n'stuff, firing on all cylinders. Copy that...
antialias_physorg
5 / 5 (1) Sep 10, 2014
Next we need to get a rocket there. We don't have the rocket engines that could get a satellite to another spiral arm that could travel the distance inside any of our lifetimes, even if we did the rocket would not survive the trip because interstellar space has micron sized (& larger) dust particles traveling at speeds that will rip holes in the hull of the rocket rendering it a useless hulk upon arrival.

I think you underestimate the distances to 'other spiral arms'. We'd be talking thousands of light years. (I.e. thousands of years to get there and thousands of years to get any info back. Even with optimal (read: light-speed) engines this isn't going to happen in anyone's lifetime. (Unless we figure out immortality.)

Forget about rockets for anything interstellar.
Lex Talonis
3 / 5 (2) Oct 06, 2014
I hope the Hubble can be used wayyyy past my life time....

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