Published: Sun, April 01, 2018
Research | By Sheri Schwartz

Researchers find a galaxy without dark matter

Researchers find a galaxy without dark matter

Luckily, their studies might be given an early boost as Hubble images of 23 other ultra-diffuse galaxies seem to suggest that three of them are similar to NGC 1052-DF2.

The ghostly galaxy doesn't have a noticeable central region, or even spiral arms and a disk, typical features of a spiral galaxy. "This thing is astonishing: a huge blob so sparse that you see the galaxies behind it". The more mass there is, the faster that stars and star clusters go. But DF2 may as well be called F-U, because that's what it's saying to scientists who thought they understood galaxies, dark matter, and really anything about our universe. The galaxy is a complete mystery, as everything about it is odd. The result of this would be that a signature usually attributed to dark matter should always be detected, and is an unavoidable outcome of the presence of ordinary matter.

This is certainly not the case with the other galaxies. In a normal galaxy, when traveled towards the end of the galaxy, fewer stars and more dark matter can be found. We've never observed it directly, but we can see the effects of its gravity throughout the universe, and it's thought to be a huge component of every galaxy that researchers have ever studied.

This was among those situations where exploration started with the expression "huh, that looks unusual".

The Dragonfly Telephoto Array is a robotic sky-watcher that peers into space from New Mexico through several regular Canon lenses all working together.

DF2 is unique in other ways, too. Which means we can also tell when it's not there.

The galaxy, charmingly named NGC1052-DF2, is about 65 million light-years away and is about one two-hundredths the mass of our own Milky Way galaxy. "This point is impressive", stated employee Pieter van Dokkum, "an enormous ball that you could browse".

At the beginning of everything, those simulations suggest, all the matter we see in the galaxy was spread out in a thin gas. "It is essentially a translucent galaxy".

Ultra-diffuse galaxies are oddities in their own right, having only been discovered in 2015 as they are very hard to detect.

'So finding a galaxy without it is unexpected.

If this turns out to be true, it may be the first galaxy of its kind - made up only of ordinary matter.

Dark matter has never been seen or measured directly because it does not emit light.

The discovery could revise or even upend theories of how galaxies are formed, they reported in the journal Nature.

Take galaxies, those giant, spinning masses of stars. In this situation, there's a marginal distinction in between the 2. Based on these indirect observations, researchers have estimated that dark matter makes up about 27 percent of our universe. "There must be more than one way to form galaxies". "So it only makes sense if dark matter is a real substance, that can be present or not, separately from the regular matter", Mack added. Since it does not, that particular explanation for dark matter, and why we can't see it, becomes less likely.

"I find this unlikely in all possible contexts", said McGaugh, who is a proponent of a "modified gravity" theory that excludes the existence of dark matter altogether. We do not see any type of sign of these impacts, so customized gravity suggestions should be wrong. And ironically, the fact that the dark matter is missing actually helps establish that it exists. Objects in it move much slower than objects in normal galaxies. One suggestion is that the gas obtained focused as it was being expelled from a galaxy merging; an additional is that it created from issue gushed out by quasars.

Each of these would certainly have to be analyzed in information to identify if it can develop the distinctive attributes of NGC1052- DF2.

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