Ghostly galaxy without dark matter stuns astronomers
30 March, 2018, 00:45 | Author: Tracy Craig
When observing a collection of galaxies called the NGC 1052 group, the array spotted an object that had shown up in other surveys of that region of the sky.
In view of the proportion in different galaxies, a confined galaxy such as NGC1052-DF2 ought to have around a hundred times more dark matter than ordinary matter.
"I spent an hour just staring at this image", lead researcher Pieter van Dokkum of Yale University says as he recalls first seeing the Hubble image of NGC 1052-DF2.
Based on these data the team discovered that the newly discovered galaxy is larger than the Milky Way, but contains about 250 times fewer stars, leading it to be classified as an ultra diffuse galaxy. After that everything else happens: gas falls into the dark matter halos, the gas turns into stars, they slowly build up, then you end up with galaxies like the Milky Way. But physicists contacted by Live Science to discuss this paper mostly said the finding made dark matter (already the dominant explanation for the universe's weirdness) look a lot more likely. "This result also suggests that there may be more than one way to form a galaxy".
Up to now, the analysis of galaxies has shown a fairly tight ratio of dark to ordinary matter.
"There is no theory that predicts these types of galaxies - how you actually go about forming one of these things is completely unknown", added co-author Allison Merritt from Yale University and the Max Planck Institute for Astronomy, Germany. For instance, dwarf galaxies have 400 times more dark matter than regular matter, whereas a galaxy like the Milky Way has about 30 times less.
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.
Instead, DF2 is a rare ultra-diffuse galaxy. That would only make sense if there was no dark matter at all acting on them, a finding confirmed when the researchers subsequently calculated the mass of the galaxy.
This is weird-and it could change what astrophysicists think dark matter is, in addition to upending their understanding of how galaxies form, says van Dokkum. Or would the current appearance of the galaxy be the result of a cataclysmic event within it? When van Dokkum and his team found NGC 1052-DF2, they expected to see something similar. Yet in this unusual galaxy, the projected signatures of these exotic effects are not seen.
Bottom line: The galaxy NGC 1052-DF2 appears to have no dark matter.
These ideas, however, still do not explain how this galaxy formed. That stellar sparseness means it does not look much like a typical spiral galaxy, but rather a loosely connected, ghostly blob of star-pocked gas and dust. They can't agree on what it's made of, how much a single particle weighs, or the best way to construct a Play-Doh diorama of it.
NGC 1052-DF2 is missing its dark matter. "In those theories, every galaxy should show a dark matter signature, as it's not due to dark matter at all but due to the laws of physics", van Dokkum explained.
We don't really know what dark matter is and why it exists... or why it doesn't. Because there's some regular issue right here, any kind of variation of customized gravity would certainly have that issue generate dark-matter-like impacts. Future observatories under construction, such as the European Extremely Large Telescope in Chile's Atacama Desert, or NASA's James Webb Space Telescope, should be able to take such measurements.
In the meantime, Syed's current attorney, Justin Brown, has celebrated the decision, tweeting in all-caps: "WE WON THE APPEAL". Classmate Asia McClain allegedly saw Syed in their high school library during the time prosecutors said Lee was murdered.
McConnell's support is critical to helping us move hemp from research and pilot programs to full commercial production". Much of the agriculture industry has already been lobbying to declassify hemp as a Schedule I controlled substance.
And Lora Davis added, "I'm super-proud of Bailey and the action and the stand that she's taking over this". She has started a movement called #leveltheplayingfield - one that treats all members of the team equally.
The Space Telescope Science Institute later announced the deadline would be pushed back to no earlier than February 1, 2019. For now, all of us will have to wait and see as NASA tries to get the project back on track and into space.
A victor has not been crowned in nearly three months, since a 20-year-old Florida man took home $451 million on January 5. Although there were no winners in Friday's drawing, IL players won more than 50,000 in prizes, from $2 to $10,000.
If you have Easter travel plans this weekend, Friday and Saturday will be days to keep an eye on as we move throughout the week. The rest of the day will be mostly cloudy with the chance for a passing shower or two and highs near 50 degrees.
Uber has marked that it has suspended its autonomous vehicle testing operations indefinitely in Arizona , California, and Toronto. The company stopped all autonomous testing immediately following the accident, and has also let its permit lapse in California.
Management or employees can participate directly in the bidding process or by way of forming a consortium, as per the memorandum. The Air India call centre was alerted by a caller, claiming that a bomb has been planted onboard the Kolkata-bound flight.
He can say whatever he wants to, but the bottom line is the Giants hold all of the cards. "We want really, really good players". Beckham will enter 2018 on the final year of his rookie deal, with the team having exercised his fifth-year option.
Meanwhile, the US will extend a tariff on pickup trucks, which was set to expire in 2021, for an additional two decades. USA officials had said Friday an agreement could be announced in the coming week.
The Argentine joined in with training over the weekend after missing La Albiceleste's 2-0 win over Italy on Friday in Manchester. Both Argentina and Barcelona will hope the 30-year-old stays in peak fitness as he attempts to fire them to a successful season.
US, South Korea come to agreement on trade deal
Under this approach, Congress does not have to approve the final agreement between the United States and South Korea. The result has been to leave well over half of U.S. imports of both steel and aluminium clear of the new tariffs.
Huawei Porsche Design Mate RS
From a design standpoint, the most noticeable thing you'll see about the Huawei P20 Pro is the Notch in the top of the phone . This camera setup features AI Image Stabilization and can also record slow-motion videos at a whopping 960 frames/second .