Connect with us

Science

New Simulation Shows Exactly What Dark Matter Would Look Like If We Could See It – Universe Today

Published

on


How do you study something invisible? This is a challenge that faces astronomers who study dark matter. Although dark matter comprises 85% of all matter in the universe, it doesn’t interact with light. It can only be seen through the gravitational influence it has on light and other matter. To make matters worse, efforts to directly detect dark matter on Earth have been unsuccessful so far.

Despite the elusive quality of dark matter, we have learned several things about it. We know that it is not just dark but cold. As a result, it clumps together, forming the seeds of galaxy clusters. It also often forms haloes around galaxies, making up the majority of a galaxy’s mass. However, there are still many unanswered questions about dark matter, so astronomers often develop new models for dark matter, comparing them to observation to test their accuracy.

One way this is done is through sophisticated computer simulations. Recently a team from the Harvard & Smithsonian Center for Astrophysics ran a detailed simulation of the dark matter cosmos, and it has produced some surprising results.

The IceCube Neutrino Detector in Antarctica has searched for WIMPs. Credit: IceCube Collaboration/NSF

The accuracy of any dark matter simulation depends upon the assumptions you make about dark matter. In this case, the team assumed dark matter consists of weakly interacting massive particles (WIMPs) with a mass about 100 times that of a proton. WIMPs are one of the more popular theories for dark matter. Similar computer simulations of WIMP dark matter have been done before. Still, this one was exceptionally high in resolution, simulating features on a scale ranging across thirty orders of magnitude.

In this simulation, dark matter formed in haloes around galaxies, just as we observe. But interestingly, it found that haloes also developed at all mass scales, from small, planet-mass haloes, to galactic haloes, to massive haloes that form around clusters of galaxies. These haloes have a similar structure, where they are most dense toward their center, becoming more diffuse at their edges. The fact that this happens at all scales makes it an explicit feature of dark matter.

The simulation shows dark mater haloes at all scales. Credit: J. Wang; S. Bose/Center for Astrophysics

While the small scale haloes are too small to be detected through their gravitational influence on light, they could tell us about how dark matter interacts with itself. One idea about dark matter is that when dark matter particles collide, they emit gamma radiation. Some gamma-ray observations have hinted at a gamma ray excess coming from the center of our galaxy, which could be caused by dark matter. In this particular model, most gamma radiation produced by dark matter would come from smaller haloes. Since the scale of a halo would affect the energy spectrum of the gamma rays, this model makes specific predictions about the gamma-ray excess we should see both in the Milky Way and other galaxies.

Dark matter remains one of the biggest unsolved problems in modern astronomy. While we would love to detect it directly, until that happens, simulations such as this are one of our most powerful tools to better understand dark matter.

Reference: Wang, J., Bose, S., Frenk, C.S. et al. “Universal structure of dark matter haloes over a mass range of 20 orders of magnitude.” Nature 585.7823 (2020): 39-42.

Let’s block ads! (Why?)



Source link

Continue Reading

Science

The detection of phosphine in Venus' clouds is a big deal – here's how we can find out if it really is life – The Conversation US

Published

on


On Sept. 14, 2020, a new planet was added to the list of potentially habitable worlds in the Solar System: Venus.

Phosphine, a toxic gas made up of one phosphorus and three hydrogen atoms (PH₃), commonly produced by organic life forms but otherwise difficult to make on rocky planets, was discovered in the middle layer of the Venus atmosphere. This raises the tantalizing possibility that something is alive on our planetary neighbor. With this discovery, Venus joins the exalted ranks of Mars and the icy moons Enceladus and Europa among planetary bodies where life may once have existed, or perhaps might even still do so today.

I’m a planetary scientist and something of a Venus evangelical. This discovery is one of the most exciting made about Venus in a very long time — and opens up a new set of possibilities for further exploration in search of life in the Solar System.

Venus as seen in the infrared by the Japanese Akatsuki spacecraft. The warm colors are from the hot lower atmosphere glowing through the cooler cloud layers above. Image credit: JAXA/ISAS/DARTS/Damia Bouic.
JAXA/ISAS/DARTS/Damia Bouic

Atmospheric mysteries

First, it’s critical to point out that this detection does not mean that astronomers have found alien life in the clouds of Venus. Far from it, in fact.

Although the discovery team identified phosphine at Venus with two different telescopes, helping to confirm the initial detection, phosphine gas can result from several processes that are unrelated to life, such as lightning, meteor impacts or even volcanic activity.

However, the quantity of phosphine detected in the Venusian clouds seems to be far greater than those processes are capable of generating, allowing the team to rule out numerous inorganic possibilities. But our understanding of the chemistry of Venus’ atmosphere is sorely lacking: Only a handful of missions have plunged through the inhospitable, carbon dioxide-dominated atmosphere to take samples among the global layer of sulfuric acid clouds.

So we planetary scientists are faced with two possibilities: Either there is some sort of life in the Venus clouds, generating phosphine, or there is unexplained and unexpected chemistry taking place there. How do we find out which it is?

A model of the Soviet Vega 1 spacecraft at the Udvar-Hazy Center, Dulles International Airport. Vega 1 carried a balloon to Venus on its way to visit Halley’s Comet in 1985.
Daderot

First and foremost, we need more information about the abundance of PH₃ in the Venus atmosphere, and we can learn something about this from Earth. Just as the discovery team did, existing telescopes capable of detecting phosphine around Venus can be used for follow-up observations, to both definitively confirm the initial finding and figure out if the amount of PH₃ in the atmosphere changes with time. In parallel, there is now a huge opportunity to carry out lab work to better understand the types of chemical reactions that might be possible on Venus — for which we have very limited information at present.

Antennas of the Atacama Large Millimeter/submillimeter Array telescope, on the Chajnantor Plateau in the Chilean Andes. The telescope was used to confirm the initial detection of phosphine in Venus’ atmosphere.
ESO/C. Malin.

Once more unto the breach

But measurements on and from Earth can take us only so far. To really get to the heart of this mystery, we need to go back to Venus. Spacecraft equipped with spectrometers that can detect phosphine from orbit could be dispatched to the second planet with the express purpose of characterizing where, and how much, of this gas is there. Because spacecraft can survive for many years in Venus’ orbit, we could obtain continuous observations with a dedicated orbiter over a much longer period than with telescopes on Earth.

But even orbital data can’t tell us the whole story. To fully get a handle on what’s happening at Venus, we have to actually get into the atmosphere. And that’s where aerial platforms come in. Capable of operating above much of the acidic cloud layer – where the temperature and pressure are almost Earthlike – for potentially months at a time, balloons or flying wings could take detailed atmospheric composition measurements there. These craft could even carry the kinds of instruments being developed to look for life on Europa. At that point, humanity might finally be able to definitively tell if we share our Solar System with Venusian life.

A concept for an aerial platform at Venus. Two connected balloons could take turns to inflate, allowing the balloon to control the altitude at which it floats. An instrument package would then hang from below the balloons.
NASA/JPL-Caltech

A new dawn for Venus exploration?

Thirty-one years have elapsed since the United States last sent a dedicated mission to Venus. That could soon change as NASA considers two of four missions in the late 2020s targeting Venus. One, called VERITAS, would carry a powerful radar to peer through the thick clouds and return unprecedented high-resolution images of the surface. The other, DAVINCI+, would plunge through the atmosphere, sampling the air as it descended, perhaps even able to sniff any phosphine present. NASA plans to pick at least one mission in April 2021.

[Deep knowledge, daily. Sign up for The Conversation’s newsletter.]

I have argued before for a return to Venus, and will continue to do so. Even without this latest scientific discovery, Venus is a compelling exploration target, with tantalizing evidence that the planet once had oceans and perhaps even suffered a hellish fate at the hands of its own volcanic eruptions.

But with the detection of a potential biomarker in Venus’ atmosphere, we now have yet another major reason to return to the world ancient Greek astronomers called Phosphorus — a name for Venus that, it turns out, is wonderfully prescient.

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Texas youth hockey coach, 29, dies from coronavirus complications days after feeling sick – Fox News

Published

on


A 29-year-old North Texas youth hockey coach died late last month from coronavirus complications after feeling sick for just three days, according to reports.

Tyler Amburgey was a “loving husband and a loving father” who had played hockey since he was 7 years old, his wife, Aimee Amburgey, told WFAA-TV in Dallas. Their daughter, Rylee, is 8 years old.

She said her husband first thought he had caught a cold traveling from rink to rink like he usually did in late summer.

“It started out like originally…with him getting like all…normal cold symptoms,” she told the station.

He then started to suffer from nausea, sleeplessness, shortness of breath, fatigue and migraines, FOX 4 in Dallas reported.

UNITED KINGDOM SEES SPIKE IN CORONAVIRUS CASES, SECOND LOCKDOWN MAY BE LOOMING 

By the third day, Aug. 29, his wife said he finally canceled his hockey practice, where some players had already tested positive, and went to bed at their home in Lavon, Texas, north of Dallas.

Soon after, she found him unresponsive in bed. She called 911 but it was too late, she told WFAA.

The medical examiner said a sleeping pill Amburgey took combined with the virus to slow his heart until it stopped, his grandfather, Paul Hinds, told the Journal Star in Peoria, Illinois. Amburgey was a former Peoria Rivermen hockey player.

“He told us sleeping pills slow your heart rate, and in combination with COVID-19, which also slows your heart, Tyler’s heart stopped,” he said. “We were unaware he had COVID-19. No one knew that when he gathered to see him.”

Amburgey played for several minor league teams before becoming a coach, The New York Times reported.

FAUCI WOULD BET ON EFFECTIVE AND SAFE CORONAVIRUS VACCINE BY NOVEMBER OR DECEMBER 

He suffered several concussions and had five hip surgeries during his career. It’s unclear if any of that made him more vulnerable to the virus.

He only tested positive for the virus after his death, Hinds told the Journal Star.

“Hockey meant everything to him,” Aimee Amburgey told The Times. “When he got a new pair of skates, he was like a kid at Christmas. You never saw anyone so pumped up about new equipment, even shin guards.”

“I just want him to be remembered for more than just a person that… passed away from COVID,” she added.

CLICK HERE TO GET THE FOX NEWS APP

Nearly 30 youth players and coaches have tested positive for the virus this month, which could be linked to a recent tournament in the area, the Dallas County Health and Human Services said, FOX 4 reported.

Let’s block ads! (Why?)



Source link

Continue Reading

Science

How to spot a Starlink satellite in the night sky – Trading U

Published

on


There are hundreds of SpaceX satellites in the sky. A successful sighting just requires a bit of luck, writes Abigail Beall

Space


16 September 2020

Denise Taylor/Getty Images

What you need

The Find Starlink website or something similar

A spot of sky viewed away from light pollution

OUR skies are filling up with satellites. Starting in May 2019, the firm SpaceX has deployed around 700 Starlink satellites into Earth orbit over 11 launches. SpaceX plans to deploy 12,000, and perhaps later 42,000, satellites with the aim of providing internet access to the entire world.

These satellites have the potential to change the way that the night sky looks. For comparison, there are only around 2600 satellites currently orbiting Earth. These days, …

Let’s block ads! (Why?)



Source link

Continue Reading

Trending