It amazes me how astronomers know this stuff...

[Arkan]

http://www.usatoday.com/tech/science/space...ed_N.htm?csp=34

 

Two galaxy clusters have been spotted colliding at what was previously thought to be impossibly high speeds.

Astronomers estimate that the galaxy cluster collision known as Abell 576 involves two clusters-each containing hundreds of galaxies-crashing into one another at over 7 million miles per hour (3,300 km/s).

 

The finding, to be detailed in an upcoming issue of Astrophysical Journal, supports previous studies which suggest galaxy clusters can collide faster than previously thought.

 

"There is now a growing body of evidence that these high collision velocities are possible," said study leader Renato Dupke of the University of Michigan.

 

Such collisions have been observed before, but the latest one is unusual in that the vantage point is from behind one of the clusters. Another well-known collision involving the Bullet Cluster takes place in the plane of the sky, so it appears to us as if the two clusters are crashing head-on.

 

 

The difference between these two vantage points is comparable to watching two cars ramming together on a movie screen versus being inside one of the cars.

 

Using the European Space Agency's XMM-Newton and NASA's Chandra orbiting X-ray observatories, researchers have spotted blobs of gas ejected from the cores of the clusters, but which will eventually fall back and merge together.

 

While individual galaxies crash into one another fairly frequently, astronomers estimate that only one in a thousand to one in a hundred galaxy clusters are involved in a collision. The amount of energy generated by a single, major cluster collision is thought to be second only to the Big Bang event that scientists think gave rise to the universe.

 

Identifying colliding systems is crucial for understanding the makeup and workings of the universe. Scientists have cited evidence from cluster collisions as some of the best available yet that dark matter and dark energy really do exist. Also, if unrecognized, collisions can lead to an underestimation of galaxy clusters by as much as 20% because of the large amounts of gas ejected during a crash.

 

Scientists rely on the mass of various galaxy clusters to estimate the cosmological parameters describing the expansion of the universe.

 

Astronomers expect that the two goliaths in Abell 576 will eventually settle into a single, gargantuan galaxy cluster.

 

Stars colliding, great. Galaxies colliding, holy geez. But clusters of hundreds of galaxies colliding? It's nigh incomprehensible. Truly awesome.

[Sand]

I hope they have insurance.

[metadigital]

Identifying colliding systems is crucial for understanding the makeup and workings of the universe. Scientists have cited evidence from cluster collisions as some of the best available yet that dark matter and dark energy really do exist. Also, if unrecognized, collisions can lead to an underestimation of galaxy clusters by as much as 20% because of the large amounts of gas ejected during a crash.

 

Scientists rely on the mass of various galaxy clusters to estimate the cosmological parameters describing the expansion of the universe.

Astronomy is still a very young science (evidenced by the large percentage of innovation accomplished by the ranks of amateurs), and is handicapped by the sheer magnitude of the tasks involved ... for example, Charon (the twin dwarf planet of Pluto) was only discovered in 1976 ... and Pluto was only discovered (in 1920) because astronomers were looking for a huge planet to explain some gravitational perturbations in Uranus and Neptune (which turned out to be completely erroneous calculations, hence Pluto has a smaller mass than Mercury, Io or Titan and is more like a Trans-Neptunian Object asteroid than a non-gaseous planet).

 

The sky is just so big that it is taking a long, long time to even begin to start mapping it. Though, the (visible) universe is so incomprehensibly large that it is almost certain that everything that can be possible IS out there, somewhere.

 

Still, colliding galactic clusters is a pretty impressive event, I'll grant you.

 

I quoted a section of the report because I am quite skeptical of "dark matter" and even moreso of "dark energy" ... I think that there must be better explanations than stretching the existing physics models beyond significant boundaries into unrecognisable parodies of what they were originally designed to explain.

[DeathScepter]

DAMN DAMN

[Gorth]

We are all crash test dummies :ninja10:

 

Looks to me like the astronomers have the Sisyphus task among scientists. How do you map an ever expanding universe completely?

[kirottu]

I bet when those two collide FPS drops like hell.

[Pop]

So which is faster then, gravity or light?

[Laozi]

Pluto was only discovered (in 1920) because astronomers were looking for a huge planet to explain some gravitational perturbations in Uranus

 

 

Yeah, that was an uncomfortable couple of weeks.

[Xard]

Wow, that's just.. unbeliavable.

 

I bet when those two collide FPS drops like hell.

 

I wonder if two 8800 GTX's could've done the job...

[metadigital]

So which is faster then, gravity or light?

Same. Interactions carried by massless quanta between objects travel at the fastest possible speed.

 

According to Coloumb's Law, electromagnetic forces travel at the fastest speed possible, the speed of light, owing to the fact that the quanta (photons) possess no mass. (At high ambient energies, the em forces "combine" with weak nuclear forces, to produce the "electroweak" force.)

 

Gravitational interactions are still so small and remote that they remain much of a mystery. Like electromagnetic interactions, the quanta (tentatively named the "graviton") has no mass (certainly nothing that we have detected so far), so it interacts on every particle according to the product of the masses and inversely of the distance apart.

 

We owe the downwards fall of the apple to the fact that matter (specifically the matter of the apple and the Earth) is electrically neutral to an accuracy of far better than 1 part in 10^20 (which is how much stronger the electromagnetic interaction is than gravity). In other words, if only one atom in 10^20 would have to lose an electron for the force of gravity to be balanced out by the electromagnetic force repulsing the bodies.

 

Interestingly, the recession speed of distant galaxies (the further they are away, the faster they are receding: Hubble's Law) does not mean that they are travelling faster, as their redshift might indicate as a function of the Doppler Effect; rather this redshift/recession speed indicates how fast SPACE ITSELF is expanding. Wrap your head around that one.

[Nick_i_am]

I bet when those two collide FPS drops like hell.

 

You freaking nerd.

[taks]

The sky is just so big that it is taking a long, long time to even begin to start mapping it. Though, the (visible) universe is so incomprehensibly large that it is almost certain that everything that can be possible IS out there, somewhere.

a point i tried to make to sand in the religion thread. no matter how minuscule the probability, the likelihood of odd things occurring is actually (probably) rather large.

 

I quoted a section of the report because I am quite skeptical of "dark matter" and even moreso of "dark energy" ... I think that there must be better explanations than stretching the existing physics models beyond significant boundaries into unrecognisable parodies of what they were originally designed to explain.

me too. these constructs are the least scientific portion of the entire BB theory. in fact, they were merely "invented" as a way to explain gravitational anomalies, as well as the apparent discrepancy with the way the universe seems to be expanding. i.e., theory said that the mass of the universe had to be more than it was in order to exhibit the expansion in the manner it did. IMO, that means go back to the drawing board and revise the original hypothesis. instead, they created dark matter (and its cousin, dark energy).

 

Interestingly, the recession speed of distant galaxies (the further they are away, the faster they are receding: Hubble's Law) does not mean that they are travelling faster, as their redshift might indicate as a function of the Doppler Effect; rather this redshift/recession speed indicates how fast SPACE ITSELF is expanding. Wrap your head around that one.

even more interestingly, in spite of the fact that hubble discovered the red-shift, and it is now dubbed "hubble's law," he did not believe it was due to a recession, or even an expanding universe. he felt that over such vast distances, photons actually lose energy, which would also create a red-shift. IMO, the jury is still out on this one, though the former explanation certainly has the majority of scientists on board. halton arp, hubble's primary student (a protege of sorts), speaks out against this regularly. he definitely sides with hubble. oh, note that there is a difference between what hubble believed and the so called "tired light" theory, though last time i checked, it was subtle.

 

taks

[Kor Qel Droma]

Pluto was only discovered (in 1920) because astronomers were looking for a huge planet to explain some gravitational perturbations in Uranus

 

 

Yeah, that was an uncomfortable couple of weeks.

 

Does it still hurt when you sit down, Laozi?

[Sand]

I bet when those two collide FPS drops like hell.

 

You freaking nerd.

You have a pokemon 4chan .gif in your sig and you are calling him a nerd?