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It's once again time for the Perseids, one of the best meteor showers of the year – CBC News

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Each August, Earth plows through a thick trail of debris left over from a passing comet. The result: A spectacular night of meteors lighting up the sky.

One of the best and most anticipated meteor showers of the year is the Perseids, which takes place from mid-July to the end of August. But peak viewing — where you’ll get a chance to see the most meteors — falls on the night of Aug. 12-13 this year, according to the International Meteor Organization. 

That’s when Earth moves through the thickest part of the debris left over from comet 109P/Swift-Tuttle, with tiny pieces of particles burning up in our atmosphere at 59 km/s.

Try this interactive map showing how Earth passes through the meteor shower:

Swift-Tuttle, which was first discovered in 1862 independently by both Lewis Swift and Horace Tuttle, makes an orbit of the sun every 133 years. The last time it was in our solar system was in 1992. Still, from all those trips around the sun, it’s left behind plenty of debris. 

Some of this debris can be bigger than the normal grain-like particles and can create beautiful bolides, or bright fireballs that light up the sky.

How to see the meteors

Though the Perseids rarely disappoint, there is one thing to contend with this year that may hamper your viewing delight: the full moon.

With the moon lighting up the sky, that means that only the brightest of meteors will be visible. Fortunately, many Perseids tend to be quite bright anyway. 

The Perseids are given their name for the constellation — Perseus. This is the point in the sky from which they seem to appear, called the radiant.

This map shows the radiant of the Perseids, which get their name name from the nearby constellation Perseus. The radiant is the point in the sky from which the meteors seem to appear. (American Meteor Society)

While some people like to look in the direction of the constellation, which rises in the northeast, it limits the number of meteors that can be seen, since they will have shorter tails. To see longer meteors (ie., with long tails), you don’t need to look directly up, but at more of an angle.

And the best thing about meteor showers is that you don’t need a telescope or binoculars, just your own eyes.

You can also keep an eye out for “earthgrazers,” meteors that skim Earth’s atmosphere and, as a result, leave a long trail behind them.

These are best viewed early in the night, when the sky is dark and the radiant is low in the east. They will be moving roughly from north to south.

To increase your chances of catching some bright meteors, you could head out ahead of the peak night of Aug. 12, or even in the days after, when the moon won’t be entirely full. Try to keep the moon behind you when stargazing to block out its glare. 

Helpful hints

Another hot tip is to try to lie down on a blanket or even on a beach lounge chair, otherwise your neck will get tired and ache from trying to look up. 

Also, put away those phones as your eyes will need to become accustomed to the dark, something that can take anywhere from 30 minutes to an hour. And remember, the more stars you can see, the more faint meteors you will catch, so try to get to as dark a location as you can, away from city lights.

Patience is your friend, so try not to give up if you haven’t seen any meteors within a few minutes. Under ideal conditions, the Perseids can produce more than 100 meteors an hour, but don’t expect to see that many. 

At this time of year, you can also catch a couple of planets: Jupiter will be low in the east and hard to miss, and Saturn will lie in the southeast.

People can also use free apps like StarWalk or SkyView (they have a night mode that displays in red in order to preserve your night vision) that allow you to hold your phone up to the sky to identify constellations, planets and more.

There’s always something to look at in the night sky, even if meteors aren’t providing a show.

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N.W.T. man among finalists in international astronomy photographer contest

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YELLOWKNIFE — A man from Yellowknife is gaining international recognition for a photo capturing a stunning display of dancing green aurora lights over the Cameron River.

Frank Bailey was the only Canadian among the finalists in the Royal Observatory Greenwich’s 2022 Astronomy Photographer of the Year competition. His time-lapse photo taken outside the Northwest Territories capital landed him the runner-up spot in the Aurorae category.

“I was of course thrilled, but also humbled at the news given the quality of the entries this year,” he said. “Once the overall standings were made fully public, it sunk in really quickly that this was a significant achievement and shows that I am heading in the right direction with my photography.”

The annual competition is the largest of its kind and showcases space and sky photography from astrophotographers around the world. More than 100 winning and shortlisted images from this year’s entries are currently on display at the National Maritime Museum in London, featuring planets, galaxies, skyscapes and other celestial bodies.

Gerald Rhemann from Austria was named the overall winner for his photo of Comet C/2021 A1, commonly known as Comet Leonard.

The top spot in the Aurorae category went to Filip Hrebenda for his photo titled “In the Embrace of a Green Lady,” showing the lights reflected in a frozen lake above Eystrahorn mountain in Hvalnes, Iceland.

Bailey’s photo, titled “Misty Green River,” was taken last September using a 15-second exposure. He said the photo was taken looking up the river toward the riffle as mist rose off the water.

Bailey, who has lived in Yellowknife for 18 years, said he first photographed the aurora when he and his wife, Karen, lived in Yukon in the early 1980s.

He said he likes to enter competitions to get feedback on his photography.

“As for future goals, I have always said it would be a good retirement job,” he said, noting he and his wife have dabbled with making sellable products such as calendars and producing prints for friends and family.

Another photo Bailey took of the aurora over the Cameron River, which he submitted to the National Wildlife Federation’s photo contest in 2020, was selected for use in a holiday card collection.

He said three of his aurora photos received a bronze award from the Epson International Pano Awards in 2021.

This report by The Canadian Press was first published Sept. 24, 2022.

This story was produced with the financial assistance of the Meta and Canadian Press News Fellowship.

 

Emily Blake, The Canadian Press

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Tonga volcano blast was unusual, could even warm the Earth – Kelowna Capital News – Kelowna Capital News

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When an undersea volcano erupted in Tonga in January, its watery blast was huge and unusual — and scientists are still trying to understand its impacts.

The volcano, known as Hunga Tonga-Hunga Ha’apai, shot millions of tons of water vapor high up into the atmosphere, according to a study published Thursday in the journal Science.

The researchers estimate the eruption raised the amount of water in the stratosphere — the second layer of the atmosphere, above the range where humans live and breathe — by around 5%.

Now, scientists are trying to figure out how all that water could affect the atmosphere, and whether it might warm Earth’s surface over the next few years.

“This was a once-in-a-lifetime event,” said lead author Holger Voemel, a scientist at the National Center for Atmospheric Research in Colorado.

Big eruptions usually cool the planet. Most volcanoes send up large amounts of sulfur, which blocks the sun’s rays, explained Matthew Toohey, a climate researcher at the University of Saskatchewan who was not involved in the study.

The Tongan blast was much soggier: The eruption started under the ocean, so it shot up a plume with much more water than usual. And since water vapor acts as a heat-trapping greenhouse gas, the eruption will probably raise temperatures instead of lowering them, Toohey said.

It’s unclear just how much warming could be in store.

Karen Rosenlof, a climate scientist at the National Oceanic and Atmospheric Administration who was not involved with the study, said she expects the effects to be minimal and temporary.

“This amount of increase might warm the surface a small amount for a short amount of time,” Rosenlof said in an email.

The water vapor will stick around the upper atmosphere for a few years before making its way into the lower atmosphere, Toohey said. In the meantime, the extra water might also speed up ozone loss in the atmosphere, Rosenlof added.

But it’s hard for scientists to say for sure, because they’ve never seen an eruption like this one.

The stratosphere stretches from around 7.5 miles to 31 miles (12 km to 50 km) above Earth and is usually very dry, Voemel explained.

Voemel’s team estimated the volcano’s plume using a network of instruments suspended from weather balloons. Usually, these tools can’t even measure water levels in the stratosphere because the amounts are so low, Voemel said.

Another research group monitored the blast using an instrument on a NASA satellite. In their study, published earlier this summer, they estimated the eruption to be even bigger, adding around 150 million metric tons of water vapor to the stratosphere — three times as much as Voemel’s study found.

Voemel acknowledged that the satellite imaging might have observed parts of the plume that the balloon instruments couldn’t catch, making its estimate higher.

Either way, he said, the Tongan blast was unlike anything seen in recent history, and studying its aftermath may hold new insights into our atmosphere.

—Maddie Burakoff, The Associated Press

RELATED: Flights sent to assess Tonga damage after volcanic eruption

EnvironmentScienceVolcano

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NASA is slamming a spacecraft into an asteroid on Monday to test planetary defence – CBC.ca

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On Monday, in what seems like a scene out of a science fiction movie, NASA will slam a spacecraft into a distant asteroid to see whether it can nudge its orbit — all in an effort to test a way to protect Earth from any potential future threats.

The good news is that there’s no need to panic: The asteroid, which is part of a binary — or two-bodied — system, is not a threat to our planet, and there are no known ones that are headed our way for at least the next 100 years. However, space agencies like the U.S. National Aeronautics and Space Administration want to be prepared should there ever be a threat.

NASA’s Double Asteroid Redirection Test (DART) is testing a way in which a spacecraft may be able to nudge an asteroid on a collision course with Earth out of its orbit.

At 7:14 p.m. ET on Monday, the refrigerator-sized spacecraft will plunge itself into Dimorphos — a moonlet that orbits its larger companion, Didymos — at roughly 6.6 km/s.

The goal isn’t to knock Dimorphos out of orbit but rather to change its 12-hour orbit around Didymos by 10 minutes. This means that scientists will know within roughly 12 hours whether they were successful.

So why target a binary asteroid system rather than a single asteroid to see whether you can change its orbit around the sun?

This image of the light from asteroid Didymos and its orbiting moonlet, Dimorphos, is a composite of 243 images taken by the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) on July 27. (NASA JPL DART Navigation Team)

“A binary system was perfect for this test,” said Mallory DeCoster, a senior scientist at Johns Hopkins University’s Applied Physics Laboratory in Maryland and part of the DART Impact Modeling Working Group.

For one, the size of Dimorphos — about 164 metres across — is perfect to illustrate whether this would be an effective way of deflecting asteroids that pose a threat to Earth. Didymos is 780 metres across.

“But then the other piece is, if we were to impact a single asteroid, in order to characterize if we changed its orbit, we would have to wait until it completed its orbit around the sun, which could take many, many years.”

The other advantage is that the binary system is relatively close to us, astronomically speaking, at just 11 million kilometres away.

Shooting gallery

NASA’s Center for Near-Earth Object Studies says that more than 90 per cent of near-Earth objects (NEOs) bigger than one kilometre have already been discovered. But that doesn’t mean we’re out of the woods when it comes to Potentially Hazardous Asteroids (PHAs).

In 2013, the Chelyabinsk asteroid — which was roughly 20 metres in diameter— exploded over parts of Russia, injuring about 1,000 people and serving as a reminder of how even a small asteroid can be dangerous.

In February 2013, a meteorite contrail was seen over Chelyabinsk, Russia, a city close to the Ural Mountains located about 1,500 kilometres east of Moscow. The Chelyabinsk asteroid, which was roughly 20 metres in diameter, exploded over parts of Russia, injuring about 1,000 people. (Chelyabinsk.ru, Yekaterina Pustynnikova/The Associated Press)

Basically, Earth flies through a shooting gallery in space. There are small chunks of debris that burn up in our atmosphere as meteors; bigger ones, like Chelyabinsk; and then even bigger ones that can be catastrophic — all left over from the formation of our solar system.

That’s why space agencies like NASA and the European Space Agency have been trying to develop ways to deflect or nudge a PHA so that its orbit changes and poses no threat to Earth.

Mike Daly, a professor at York University’s Lassonde School of Engineering in Toronto and a co-investigator on DART, said one of the most popular concepts is deflecting asteroids before they become a real threat. But that means we need to have advance warning that one is headed our way.

“So the simplest method is the one that DART is doing, which is essentially to take a spacecraft at high speed and crash it into the asteroid and use that transfer of the energy from the spacecraft to the asteroid to move it along,” he said.

This infographic shows the potential effect of DART’s impact on the orbit of Dimorphos. (NASA/Johns Hopkins APL)

However, the science behind asteroid deflection in this manner is about more than just the combination of the spacecraft’s size and incredibly high speed, called a hypervelocity impact.

“In a hypervelocity impact, you induce this pressure wave into the target that causes a lot of new physics to happen,” Johns Hopkins University’s DeCoster said.

“So what will happen, or what we think will happen, is that the size of the spacecraft might actually not matter that much. It might actually be: How does the asteroid respond to this pressure wave that is induced due to the hypervelocity impact? And we think that it will likely spew out a lot of material in the form of ejecta. And this ejecta might actually have a major component for changing the orbit. So much ejecta might get spewed out that that piece might matter more than the incoming energy from the spacecraft in changing its orbit.”

The DART team hopes that an onboard camera, called DRACO, will show the close approach and then suddenly go black, which would be indicative of an impact.

This map shows the 38 telescopic facilities in space and around the globe that are expected to observe the Didymos asteroid system in support of DART’s global observation campaign after impact. Numerical figures in parentheses next to the telescope names indicate the telescope size. (NASA/Johns Hopkins APL/Nancy Chabot/Mike Halstad)

But there’s a straggler tagging along behind DART, by about three minutes: the Italian Space Agency’s Light Italian Cubesat for Imaging of Asteroids, or LICIACube. Its job is to photograph the impact, study the plume of ejecta and help determine the morphology of the asteroid, as they can be made of iron, rock or just rocky clumps held together by gravity.

As this is the first test of a form of planetary defence, scientists are eagerly anticipating not only the impact of the event itself but what they will learn from it and, most importantly, what this may mean for the future of protecting Earth in the future. Telescopes from around the world will be observing the event and collecting followup data.

“We’re really the first generation that can protect ourselves from these potentially catastrophic impacts,” York University’s Daly said. “And, you know, fortunately the really catastrophic ones don’t happen very often, but they could happen, and never before have we been able to change our fate. So I think it’s really up to us, given the potentially large consequences of not paying attention and our ability to do it.”

The event will be broadcast on NASA TV, which is available online and through its app.

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