Tag Archives: halo

The Milky Way’s halo might be thousands of times hotter than the sun’s surface

Artist’s illustration of the halo of hot gas surrounding the Milky Way galaxy (Credit: NASA)

Our home galaxy, the Milky Way, contains a halo that consists of a hazy fog of dust, gas, and dark matter. Scientists already believe the enormous halo to measure at least 300,000 light-years across (as a reference point, the Milky Way itself reaches 100,000 light-years across space).

Now, a new study out of Ohio State University (OSU) suggests that the extreme temperatures the researchers found in a previous OSU analysis — up to 10 million degrees Kelvin, or about 18 million degrees Fahrenheit — could possibly be found throughout the whole halo. Prior it was believed that only certain parts of the halo could reach the high temperature.

“We can’t say for sure that it is everywhere, because we have not analyzed the entire halo,” said Smita Mathur, professor of astronomy at OSU. “But we know now that the temperatures we saw in the first study definitely are not unique, and that is very exciting.”

A recent April study out of the University of California, Irvine found that the Milky Way could be flinging stars into the outer halo. The movements are believed to be triggered by powerful supernova explosions. Supernovas occur when stars explode and lose most of their mass.

Using “hyper-realistic” computer simulations from the Feedback in Realistic Environments 2 project (FIRE 2), the scientists modeled the disruptions in galactic rotations that would otherwise be considered orderly.

“These highly accurate numerical simulations have shown us that it’s likely the Milky Way has been launching stars in circumgalactic space in outflows triggered by supernova explosions,” study author James Bullock, dean of the university’s School of Physical Sciences and a professor of physics and astronomy. “It’s fascinating, because when multiple big stars die, the resulting energy can expel gas from the galaxy, which in turn cools, causing new stars to be born.”

The data from the Ohio State report came from an X-ray observatory telescope run by the European Space Agency. That telescope, called XMM-Newton, collects data in X-rays that would have otherwise been blocked by Earth’s atmosphere.

“It showed us that the halo was much hotter than we had known, but it didn’t show us whether that was the case throughout the galaxy, or if the telescope had picked up an aberration caused by an unknown force coming from the direction where the telescope was pointed,” Mathur said.

Anjali Gupta, a visiting astronomy researcher at OSU, analyzed data from Suzaku, a Japanese X-ray satellite telescope, which collected spectrum data from the Milky Way’s halo in four different directions. That analysis confirmed their earlier findings — that the halo is much hotter than had previously been known.

However, it still remains to be seen if the same conditions exist for halos surrounding those galaxies far, far, away.

The new findings were presented at the annual meeting of the American Astronomical Society, held online this week because of the COVID-19 pandemic.

Artist's representation of what a Y-class brown dwarf might look like.

Researchers spot the biggest brown dwarf ever, trailing at the edge of the Milky Way

An international research team has found the largest brown dwarf we’ve ever seen, and it has ‘the purest’ composition to boot. Known as SDSS J0104+1535, the dwarf trails at the edges of the Milky Way.

An artists' representation of a brown dwarf with polar auroras.

An artists’ representation of a brown dwarf with polar auroras.
Image credits NASA / JPL.

Brown dwarfs — they’re like stars, but without the spark of love. They’re much too big to be planets but they’re too small to ignite and sustain fusion, so they’re not (that) bright and warm and so on. Your coffee is probably warmer than some Y-class brown dwarfs, which sit on the lower end of their energy spectrum. The coldest such body we know of, a Y2 class known as WISE 0855−0714, is actually so cold (−48 to −13 degrees C / −55 to 8 degrees F) your tongue would stick to it if you could lick it.

But they can still become really massive, as an international team of researchers recently discovered: nestled among the oldest of stars in the galaxy at the halo of our Milky Way, some 750 light years away from the constellation Pisces, they have found a brown dwarf which seems to be 90 times more massive than Jupiter — making it the biggest, most massive brown dwarf we’ve ever seen.

Named SDSS J0104+1535, the body is also surprisingly homogeneous as far as chemistry is concerned. Starting from its optical and near-infrared spectrum measured using the European Southern Observatory’s Very Large Telescope, the team says that this star is “the most metal-poor and highest mass substellar object known to-date”, made up of an estimated 99.99% hydrogen and helium. This would make the 10-billion-year-old star some 250 times purer than the Sun.

Artist's representation of what a Y-class brown dwarf might look like.

Y u so cold?
Image credits NASA / JPL-Caltech.


“We really didn’t expect to see brown dwarfs that are this pure,” said Dr Zeng Hua Zhang of the Institute of Astrophysics in the Canary Islands, who led the team.

“Having found one though often suggests a much larger hitherto undiscovered population — I’d be very surprised if there aren’t many more similar objects out there waiting to be found.”

From its optical and infrared spectrum, measured using the Very Large Telescope, SDSS J0104+1535 has been classified as an L-type ultra-cool subdwarf — based on a classification scheme established by Dr Zhang.

The paper “Primeval very low-mass stars and brown dwarfs – II. The most metal-poor substellar object” has been published in the journal Monthly Notices of the Royal Astronomical Society.

Massive analysis of gamers’ habits reveals how to best reach excellence in any skill

Scientists are learning tips and tricks for reaching excellence in what most people would call an unlikely source — gamers. A team at Brown University has analyzed countless hours of competitive play to see which practices work best when trying to improve a skill.

Image credits Gerd Altmann.

It’s easy to dismiss gamers as slack-offs, but what most people who don’t partake in video gaming fail to understand is how competitive and skill-centric some game communities can be. Sure, there’s a lot of stuff out there that’s designed purely as a time-and-money sink — a title about crushing candies comes to mind. But in the kind of games that attract competitive players, the ones you’ll see in eSport competitions, you live or die by your skill. Through their very nature, by pitting player against player, these games rear their community with a single overarching goal — to git gud.

Mastering a game isn’t much different from mastering anything else. Mostly, it comes down to practice. So when you think about it, studying gamers, a demographic in which individuals continually order themselves after levels of excellence/skill at a common task, can yield some valuable insight into which practice patterns work best.

Which is exactly what a team led by a Brown University computer scientist has done. They’ve analyzed data gathered from thousands of online matches of Halo: Reach and StarCraft 2.

“The great thing about game data is that it’s naturalistic, there’s a ton of it, and it’s really well measured,” said Jeff Huang, a computer science professor at Brown and lead author of the study.

“It gives us the opportunity to measure patterns for a long period of time over a lot of people in a way that you can’t really do in a lab.”

The results obtained from the first showed how different patterns of play affected skill improvement rates, while the latter showed how highly successful players’ unique and consistent “rituals” play a key part in their success.

There were several reasons for choosing these games: they’re both hugely popular. They have built-in ranking systems which sort players according to their success, providing the team with a solid estimation of individual skill levels. They’re also both highly competitive games, but play very differently from one another.

From zero to hero

Halo: Reach is a first-person shooter, a genre of games in which players take on the role of a single character and have to use a plethora of weapons to battle others. FPS games generally rely on motor skills (e.g. hand-eye coordination), reaction and decision speed, as well as individual tactical choices. One of the most popular game modes is Team Slayer, where players are placed on opposing teams which compete to get the most kills by the end of the 10-15 minute game time.

To make sure the game is fair for everyone, the game uses a metric system called TrueSkill — whose ratings are constantly updated with a player’s performance following each match — to put the together teams of roughly equal ability. TrueSkill gave Huang and his colleagues the means to see how playing habits influence gamers’ skill acquisition. They looked at data mined from all the online Halo matches played since the game’s release — totaling a staggering seven months of continuous game-play.

People who played the most matches every week (more than 64) had the largest overall increase in skill over time. But simply playing a lot isn’t the most efficient way to improve your skill, the team reports. Over the first 200 matches played, people who played 4-8 matches a week showed the most improvement on a per-match basis. They were followed by those who played 8-16 matches every week.

“What this suggests is that if you want to improve the most efficiently, it’s not about playing the most matches per week,” Huang said.

“You actually want to space out your activity a little bit and not play so intensively.”

The team also looked at the effect breaks had on a player’s skill. Players who took short breaks — i.e. one or two days — showed some decrease in skill in the first match following the downtime, but no decrease in their second one. Longer term breaks, however, had more pronounced effects on their efficiency. The effects of a 30-day break, for example, lasted for around 10 matches. So the lesson here is moderation — don’t overdo it on either the practice or the rest.

Tap it like it’s (a) hot (key)

The second study focused on the real-time strategy game Starcraft 2. Like other RTS games, it puts players in control of an entire army. They have to secure resources and manage an economy, build up bases and infrastructure, train their forces, and direct them in battle — often taking place on multiple fronts, with hundreds of units at a time. It’s an entirely different game from Halo, promoting management skills, large-scale tactical choices, sustained attention, and strategical thinking.

By comparing the in-game habits of elite players to those of average or lower skill, the team found one major difference: heavy use of hotkeys. These are customizable keyboard shortcuts which enable complex commands to be issued much more quickly. Less skilled players usually gave orders using the mouse. Elite players universally prefer hotkeys, the team found.

Image credits: Josef Glatz.

This gives them a huge advantage. For instance, the task of finding a free worker and selecting it with the mouse, clicking on the build icon, selecting the right building, and finally placing it in the desired location — which can take 4-5 seconds — can be done in under a second with hotkeys. Just press F1, B, B, click, and you have a barracks under construction. Skilled players can issue up to 200 different orders a minute in typical matches with hotkeys, dwarfing anything possible through the mouse alone.

But that’s pretty common knowledge in the StarCraft player-base. Hotkeying is the one skill all my friends say has improved their game the most — and we’re nowhere near an ‘elite’ level of play. What top players do differently is that they form unique hotkeying habits and stick with them. These habits are so distinctive and consistent, in fact, that the team was able to identify specific players with over 90% accuracy just by looking at how they hotkey. These habits are almost like a second nature, the researchers say, enabling players to issue commands efficiently when pressure is on.

They also seem to “warm up” this skill in every match. The study shows that even in the very early stages of a game when there’s almost nothing going on, these players will rapidly scroll through their hotkey habits issuing dummy commands to whatever units they have available.

“They’re getting their minds and bodies into the routines that they’ll need when they’re at peak performance later in the game,” Huang said.

“They’re getting themselves warmed up.”

Mastering mastery

Huang hopes their research will help people can improve their performance in other areas of life. Professions which require specialists to pay attention to lots of different elements at once could benefit from a “warming up” similar to that in StarCraft.

“Air traffic controllers come to mind,” he said.

“Maybe when someone first gets in the seat, they should take a few moments and re-enact what they do until they can get warmed up and in the zone.”

The results of the Halo study confirm previous cognitive research, he adds, which suggests that moderate activity coupled with short breaks can improve learning efficiency.

“People have seen this for other things, like studying.”

“Cramming is generally regarded as less efficient than doing smaller bits of studying throughout the semester. I think we’re seeing something similar here in our study.”

Taken together, the results show that the best way to become good at something is to “practice consistently, stay warm,” Huang concludes.

The full paper “Master Maker: Understanding Gaming Skill Through Practice and Habit From Gameplay Behavior” has been published in the journal Topics in Cognitive Science.

Scientists uncover unique speed and direction of Milky Way’s spinning ‘halo’

A team of NASA-funded astronomers from the University of Michigan has discovered that the hot gas in the Milky Way’s halo is spinning in the same direction, as well as at a similar speed, as its disk.

Illustration of the Milky Way's high temperature gaseous halo (seen in blue). Credit: NASA/CXC/M.Weiss/Ohio State/A Gupta et al.
Illustration of the Milky Way’s high temperature gaseous halo (seen in blue).
Credit: NASA/CXC/M.Weiss/Ohio State/A Gupta et al.

The Milky Way’s disk contains our stars, planets, gas and dust, and the findings from the new study shed light on how stars, planets, and galaxies such as our own form from individual atoms.

“This flies in the face of expectations,” said Edmund Hodges-Kluck of the University of Michigan and lead author of the study. “People just assumed that the disk of the Milky Way spins while this enormous reservoir of hot gas is stationary – but that is wrong. This hot gas reservoir is rotating as well, just not quite as fast as the disk.”

The study used data from the European Space Agency’s (ESA’s) XXM-Newton telescope to examine the nature of the Milky Way’s gaseous halo, which is composed of ionized plasma and is several times larger than its disk.

Motion creates shifts in the wavelengths of light and using lines of hot oxygen, the team was able to pinpoint these shifts. These shift measurements revealed that the our galaxy’s halo spins in the same direction as its disk, as well as at a similar speed – the halo spins at approximately 400,000 miles per hour compared to the disk, which spins at around 540,000 miles per hour.

“The rotation of the hot halo is an incredible clue to how the Milky Way formed,” Hodges-Kluck said. “It tells us that this hot atmosphere is the original source of a lot of the matter in the disk.”

The data could help scientists better understand the nature of dark matter, the mysterious undetectable matter that is believed to make up around 80 percent of the universe, as well as the other missing “normal” matter that appears to be missing from galaxy disks. The answers to these missing matter mysteries could lie in the gaseous halos of the universe’s many galaxies.

“Now that we know about the rotation, theorists will begin to use this to learn how our Milky Way galaxy formed – and its eventual destiny,” said Joel Bregman, a professor of astronomy from the University of Michigan and senior author of the study. “We can use this discovery to learn so much more – the rotation of this hot halo will be a big topic of future X-ray spectrographs.”

Journal Reference: THE ROTATION OF THE HOT GAS AROUND THE MILKY WAY. 27 April 2016. 10.3847/0004-637X/822/1/21

Spectacular solar halo seen in Mexico [with explanation… and memes]

A stunning round solar halo caused a social media frenzy – people were out in the streets, taking photos, sharing them, while scientists were also excited to see such a rare phenomenon. But what are solar halos, and why did this one appear in Mexico?

Generally speaking, a halo is an optical phenomenon produced by light interacting with ice crystals suspended in the atmosphere. Basically, millions of ice crystals in the atmosphere refract the light, and when light hits them at just the right angle, a halo is formed. The most common type of halo, as was the case here, is called the 22° halo.

It’s called that because it forms a circle with a radius of approximately 22° around the Sun, or occasionally the Moon. As light passes through the 60° apex angle of the hexagonal ice prisms it is deflected twice resulting in deviation angles ranging from 22° to 50°. The angle of minimum deviation is about 22°. As no light is refracted at angles smaller than 22° the sky is darker inside the halo.

In folklore, such halos are generally a bad omen – either a sign of a storm to come, or just of… something bad (superstitions, yeah).

“I have received some 30 phone calls from people who are scared and think that it’s a bad omen, others think it means it will rain more than expected,” the coordinator of the National Weather Service, Juan Manuel Caballero, told said in an interview.

Of course, the manifestation is quite benign; it is possible that it’s followed by a storm, but the halo can appear without an ensuing storm. Some people took it more lightly, and even made memes with it:



Hubble Discovers Huge Halo Around Andromeda Galaxy

In an article published in the Astrophysical Journal last week, astronomers described a massive halo around the Andromeda Galaxy, extending up close to Earth. The team spotted the halo through NASA’s Hubble Space Telescope and consider it one of the galaxy’s most important features.

The Andromeda Galaxy seen in infrared by the Spitzer Space Telescope, one of NASA’s four Great Space Observatories. Image via Wikipedia.

“Halos are the gaseous atmospheres of galaxies,” Lehner said in a statement released by Notre Dame News. “The properties of these gaseous halos control the rate at which stars form in galaxies.”

The Andromeda Galaxy is located about 2.5 million light years from our own, and it is the nearest galaxy to the Milky Way. It’s the largest galaxy in the Local Group. The halo itself is huge, extending one million light years from the galaxy, containing about as much mass as half the stars in Andromeda.

So how is it that we didn’t discover something as huge as this until now? Well, as the team explains, the gas in the halo is invisible, so they had to rely on an indirect method to view it, using light from 18 different quasars. Quasars are a class of amazing objects – compact regions in the center of a massive galaxy surrounding a central supermassive black hole. They rotate at high speeds and emit electromagnetic radiation which can be detected when they are faced towards the Earth. Imagine a rotating lighthouse – you can see its light when it’s facing you.

“As the light from the quasars travels toward Hubble, the halo’s gas will absorb some of that light and make the quasar appear a little darker in just a very small wavelength range,” the study’s co-author J. Christopher Howk said.

Halos have been observed before, but never before has one so big been imaged. We don’t know if the Milky Way also has a halo; if it does, then the two halos might merge sooner than the two galaxies, and the consequences are still not yet understood.

If you’re worried about the collision of the two galaxies, then you should know that’s only going to happen about 4 billion years from now.