Recent discovery challenges what scientists thought about birth of galaxies

Recent discovery challenges what scientists thought about birth of galaxies

Recent discovery challenges what scientists thought about birth of galaxies

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. He points out that the galaxy, memorably named NGC1052-DF2, is orbiting another one.

There have been several ideas that have floated around regarding the true nature of dark matter, and discoveries like this will only push astronomers to unlocking its secrets. It's paradoxical, but the galaxy lacking dark matter could teach us a lot about dark matter itself.

But after 30-plus years of telescope observations, most researchers do agree on one thing: The universe contains a lot of it. Astrophysicists think dark matter dominates ordinary matter in the universe by more than five times because galaxies rotate too fast for their visible star-stuff to handle.

In Dragonfly images, NGC 1052-DF2 looked like a standard ultra-diffuse galaxy.

"This invisible, mysterious substance is the most dominant aspect of any galaxy", Pieter van Dokkum, a Yale professor and lead author of the study, explains. From the W.M. Keck Observatory, they measured the velocity of clusters of stars (called globular clusters) within DF2 and found they were moving slower than expected. When the team studied the behaviour of these clusters, they found that the stars seemed to account for all of the galaxy's mass, leaving no room for dark matter. In fact, it is believed that galaxies start their lives as blobs of dark matter.

Dark matter is still a great mystery for astronomers and scientists. "So finding the opposite, namely an absence of dark matter, really came out of the blue for us", he said. Using observations from the Hubble Space Telescope and the Dragonfly Telephoto Array, the team discovered that the galaxy appeared dramatically different than others they had seen. By following the movement of 10 inserted star clusters, the group could decide how much mass is tucked into the system. Scientists can see right through it like a phantom floating over a bed in a haunted house. "We know so little about dark matter that any new constraint is welcome", says van Dokkum.

"Now wait", you may be thinking, "how does a lack of dark matter make a galaxy transparent when the substance is invisible?" The galaxy is a complete mystery, as everything about it is unusual. "This thing is astonishing: a big blob so sparse that you see the galaxies behind it". It has its own separate existence apart from other components of galaxies. By measuring their motions, the astronomers could calculate the mass of material enclosed inside their orbits.

Some have thought that what we think of as "dark matter" isn't actually another form of matter, but may be just another expression of how normal matter affects the universe.

To imagine this process, you can visualize dark matter as a diffuse collection of individual particles-unlike ordinary matter, which clumps into stars and planets. Utilizing the quantity of light given off by the galaxy created a quote of the overall mass of celebrities in the galaxy that was likewise in the neighborhood of 108.

"Every galaxy we knew about before has dark matter, and they all fall in familiar categories like spiral or elliptical galaxies", van Dokkum said. "They're much smaller objects", she told BBC News.

That's because some scientists have been arguing in recent years that dark matter is not really there - that it's simply a change in the laws of gravity that we don't understand.

The research team identified a few ways that DF2 may have formed. "It's like you take a galaxy and you only have the stellar halo and globular clusters, and it somehow forgot to make everything else", noted van Dokkum.

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