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How to catch your once-in-a-lifetime look at Comet Leonard – CBC News



Your once-in-a-lifetime chance to see a green comet named C/2021 A1 — a.k.a. Leonard — is here. Astronomy experts, including the comet’s discoverer, offer tips on when and how to see the comet.

What is Comet C/2021 A1?

Like other comets, Leonard is a ball of frozen gas, rocks and dust. When its orbit brings it close to the sun, the heat causes some of that material to vapourize, which makes it glow and sprout a tail of gas and dust. 

Why is this comet causing so much excitement?

While many comets pass through our solar system, few come close enough to the sun or the Earth for us to see them.

This week, it may be possible to see Leonard even without binoculars, the experts said.

“Brighter comets are rare, so it’s definitely worth making an effort to see them,” said Chris Vaughan, an operator at the David Dunlap Observatory in Richmond Hill, Ont., and a volunteer with the Royal Astronomical Society of Canada. Vaughan recently posted about Comet Leonard on his Astronomy Skylights blog.

Leonard’s discoverer, Greg Leonard, has discovered 13 comets, but said this one feels “like hitting the celestial jackpot,” because of how visible it will be. 

“It’s a real dream come true and it’s very, very humbling,”  he told CBC’s As It Happens on Dec. 2.

When is the best time to see the comet?

Right now, the comet is visible in the Northern Hemisphere in the eastern sky to people using binoculars from anywhere in Canada in the early morning, he said. 

It’s expected to get brighter and closer to the horizon every morning until Saturday, Dec. 11. 

For those who want to see the comet, Vaughan recommends going out in the early morning over the next couple of days, if the sky is clear. He said an area away from city lights, with a clear view of the horizon to the east, would offer the best view. By returning on subsequent mornings, you should be able to notice the change, he said.

If the weather co-operates, Friday and Saturday mornings around 6 a.m. may be the best bets for a good view. At that point, Vaughan said, Leonard should still be high enough that it won’t be blocked by trees and houses or distorted by the atmosphere.  

On Sunday, Dec. 12, the comet should make its closest approach to Earth, then disappear the next day for Northern Hemisphere viewers.

It’s expected to return Monday after sunset, as it heads away from the Earth toward the sun, getting fainter over the following weeks.

“But it’ll never get very high above the horizon,” Vaughan said. “The pre-dawn is your best chance [for viewing], the next few days.”

How can you find it in the night sky?

It will be in the eastern sky below and to the left of the bright star Arcturus in the constellation Bootes. 

This map of the sky at 6 a.m. (no matter where you are in Canada) shows where to look for Comet Leonard this week. It’s based on a diagram created by Chris Vaughan with the software Stellarium for his blog Astronomy Skylights on his website, AstroGeo. (CBC News)

Justin Anderson, an astro-photographer who lives north of Brandon, Man., managed to capture the comet earlier this week, and said he plans to keep going out to take more photos.

He said he uses mobile apps such as Star Walk and Stellarium that allow you to point your phone up at the sky, show a map of the stars in that region and pinpoint where the comet is expected to be.

“With binoculars, it was pretty difficult to find it, just because the tail is quite dim,” Anderson said. 

It’s easier to find with a camera, he said, which is more sensitive to faint objects than our eyes. The camera doesn’t need to be fancy, Anderson said, although zooming in may help. 

“Put your camera in that direction and take a photo if you don’t see it,” he said. “You might have to move it a little bit more and take another photo until you do see it. But it is very green on the camera, and you do see a little bit of a tail behind it.”

When will it become visible to the naked eye?

As of Dec. 7, Leonard was 46.25 million kilometres away, with a brightness magnitude of 6.9. It will need to reach a magnitude between four and five to be visible in rural areas, Vaughan said,which it is predicted to do this weekend.

The @cometleonard Twitter account provides regular updates on the comet’s magnitude.

Magnitude five is dimmer than last year’s Comet NEOWISE, which topped out between magnitude one and two, similar to the North Star, Polaris. 

But no one knows if Comet Leonard will follow predictions.

“The only thing consistent about comets is their unpredictability,” said Greg Leonard. “And a famous comet hunter once said comets are like cats. Both have tails and both do precisely what they want.”

Where did Comet Leonard get its name?

Comets are generally named after their discoverers.  Greg Leonard works for the NASA-funded Catalina Sky Survey at the University of Arizona in Tucson, hunting and tracking near-Earth asteroids.

“On occasion, we stumble into an unknown comet,” he told CBC.

This is actually not the only Comet Leonard. Greg Leonard has discovered 12 other comets — all called Leonard.

But they all have different years, letters and numbers attached.

Greg Leonard poses with the Catalina Sky Survey Telescope, used to find near-Earth asteroids. While doing that, he has found 13 comets, all named after him, including Comet Leonard C/2021a1. (C. Scherer)

On Jan. 3, C/2021 A1 became the first comet discovered this year. The “A” means it was found in the first half of January.

Why do we only get one chance to see it?

Comet Leonard is expected to pass by once and never again.

The comet formed about 4.5 billion years ago and comes from about 550 billion kilometres away, or 3,700 times the distance between the sun and the Earth. 

“It’s been inbound toward the inner solar system for the past 35,000 years,” Leonard said. 

It’s zooming through space at 70 kilometres per second, he said. “That’s enough speed for it to get flung away from our solar system.”

It may arrive in some other star system millions and millions of years from now.

In the meantime, “just appreciate that this beautiful celestial object is up in the sky,” Leonard said. 

“I sure wish everybody clear skies and the opportunity to have a look and see it for themselves.” 

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Scientists study trajectory of meteorite that landed in B.C. in October – Red Deer Advocate



VANCOUVER — Scientistsstudying a meteorite that landed next to a British Columbia woman’s head last year say it was diverted to that path about 470 million years ago.

The small meteorite broke through a woman’s ceiling in Golden, B.C., in October, landing on her pillow, next to where she had been sleeping moments earlier.

Philip McCausland,a lead researcher mapping the meteorite’s journey, said Monday they know the 4.5-billion-year-old rock collided with something about 470 million years ago, breaking into fragments and changing the trajectory of some of the pieces.

McCausland, who’s an adjunct professor at Western University in London, Ont., said the meteorite is of scientific significance because it will allow scientists to study how material from the asteroid belt arrives on Earth.

“There’s 50,000 to 60,000 identified meteorites now in the world, but most have no context. We don’t know really where they came from,” he said.

“In cases where we have known orbits, where they were observed coming in well enough that we can reconstruct what the orbit was before it hit the Earth’s atmosphere, we can actually (determine) where they came from in the asteroid belt. Golden is one of those,” he said, referring to the location of where the meteorite landed.

Researchers determined the meteorite is an L chondrite, one of the most commonly found types of meteorites to fall to Earth. Despite this, he said only about five L chondrites have known orbits.

He said the Canadian team is now working with scientists in Switzerland, the U.K., U.S. and Italy to learn more about the meteorite and its path to Golden.

“We know we’re still going to get something interesting out of this,” McCausland said. “We actually do want to get a good handle on how things get delivered from the asteroid belt, and this is a useful part of putting that together.”

Most of the meteorite has been returned to Ruth Hamilton, the woman who had the close call, and McCausland said it’s up to her to decide what to do with it.

Whether she decides to keep, sell or donate the rock, he said there is cultural significance of the rock to Canada. If she sells it to an international buyer, she would be required to go through the exportation process, he said.

Hamilton said she hasn’t yet made up her mind on what to do with the meteor. It’s currently sitting in a safety deposit box.

“I don’t have any plans for it right now, but once they’re done analyzing it, I’ll get all the documentation that proves it’s a meteorite,” she said. “It’s going to be officially named the Golden Meteorite.”

Before her roof is permanently repaired this spring, Hamilton said she intends to remove the section where the meteorite crashed through to keep it preserved alongside the rock.

McCausland said the research will likely conclude in May, and the scientists will then publish their work in an academic journal.

“Whenever something like this happens, I like to tell people it could happen to any of us; anyone can find a meteorite. It’s unlikely one will crash through your roof, but it can happen,” McCausland said. “It’s nature and, if anything, it’s a reminder that we’re part of something bigger.”

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Elon Musk’s Starlink Is Causing More Streaks to Appear in Space Images – Gizmodo



A Starlink satellite streak appears in a ZTF image of the Andromeda galaxy, as pictured on May 19, 2021.
Image: ZTF/Caltech

Researchers at the Zwicky Transient Facility in California have analyzed the degree to which SpaceX’s Starlink satellite constellation is affecting ground-based astronomical observations. The results are mixed.

The new paper, published in The Astrophysical Journal Letters and led by former Caltech postdoctoral scholar Przemek Mróz, offers some good news and some bad news. The good news is that Starlink is not currently causing problems for scientists at the Zwicky Transient Facility (ZTF), which operates out of Caltech’s Palomar Observatory near San Diego. ZTF, using both optical and infrared wavelengths, scans the entire night sky once every two days in an effort to detect sudden changes in space, such as previously unseen asteroids and comets, stars that suddenly go dim, or colliding neutron stars.

But that doesn’t mean Starlink satellites, which provide broadband internet from low Earth orbit, aren’t having an impact. The newly completed study, which reviewed archival data from November 2019 to September 2021, found 5,301 satellite streaks directly attributable to Starlink. Not surprisingly, “the number of affected images is increasing with time as SpaceX deploys more satellites,” but, so far, science operations at ZTF “have not yet been severely affected by satellite streaks, despite the increase in their number observed during the analyzed period,” the astronomers write in their study.

The bad news has to do with the future situation and how satellite megaconstellations, whether Starlink or some other fleet, will affect astronomical observations in the years to come, particularly observations made during the twilight hours. Indeed, images most affected by Starlink were those taken at dawn or dusk. In 2019, this meant satellite streaks in less than 0.5% of all twilight images, but by August 2019 this had escalated to 18%. Starlink satellites orbit at a low altitude of around 324 miles (550 km), causing them to reflect more sunlight during sunset and sunrise, which creates a problem for observatories at twilight.

Astronomers perform observations at dawn and dusk when searching for near-Earth asteroids that might appear next to the Sun from our perspective. Two years ago, ZTF astronomers used this technique to detect 2020 AV2—the first asteroid entirely within the orbit of Venus. A concern expressed in the new paper is that, when Starlink gets to 10,000 satellites—which SpaceX expects to achieve by 2027—all ZTF images taken during twilight will contain at least one satellite streak. Following yesterday’s launch of a Falcon 9 rocket, the Starlink megaconstellation consists of over 2,000 satellites.

In a Caltech press release, Mróz, now at the University of Warsaw in Poland, said he doesn’t “expect Starlink satellites to affect non-twilight images, but if the satellite constellation of other companies goes into higher orbits, this could cause problems for non-twilight observations.” A pending satellite constellation managed by OneWeb, a UK-based telecommunications firm, will orbit at an operational altitude of 745 miles (1,200 km), for example.

Launch of a SpaceX Falcon 9 rocket with 49 Starlink satellites on board, as imaged on January 18, 2022.
Launch of a SpaceX Falcon 9 rocket with 49 Starlink satellites on board, as imaged on January 18, 2022.
Photo: SpaceX

The researchers also estimated the fraction of pixels that are lost as a result of a single satellite streak, finding it to be “not large.” By “not large” they mean 0.1% of all pixels in a single ZTF image.

That said, “simply counting pixels affected by satellite streaks does not capture the entirety of the problem, for example resources that are required to identify satellite streaks and mask them out or the chance of missing a first detection of an object,” the scientists write. Indeed, as Thomas Prince, an astronomer at Caltech and a co-author of the study pointed out in the press release, a “small chance” exists that “we would miss an asteroid or another event hidden behind a satellite streak, but compared to the impact of weather, such as a cloudy sky, these are rather small effects for ZTF.”

SpaceX has not responded to our request for comment.

The scientists also looked into the measures taken by SpaceX to reduce the brightness of Starlink satellites. Implemented in 2020, these measures include visors that prevent sunlight from illuminating too much of the satellite’s surface. These measures have served to reduce the brightness of Starlink satellites by a factor of 4.6, which means they’re now at a 6.8 magnitude (for reference, the brightest stars shine at a magnitude 1, and human eyes can’t see objects much dimmer than 6.0). This marks a major improvement, but it’s still not great, as members of the 2020 Satellite Constellations 1 workshop asked that satellites in LEO have magnitudes above 7.

The current study only considered the impacts of Starlink on the Zwicky Transient Facility. Every observatory will be affected differently by Starlink and other satellites, including the upcoming Vera C. Rubin Observatory, which is expected to be badly affected by megaconstellations. Observatories are also expected to experience problems as a result of radio interference, the appearance of ghost-like artifacts, among other potential issues.

More: Elon Musk Tweets Video of ‘Mechazilla’ Tower That Will Somehow Catch a Rocket.

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Earth's core is rapidly cooling, study reveals. Is our planet becoming 'inactive'? – USA TODAY



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Planet Earth hits 6th warmest year on record

Earth simmered to the sixth hottest year on record in 2021, according to several newly released temperature measurements. (Jan. 13)


Earth’s interior is cooling faster than we previously estimated, according to a recent study, prompting questions about how long people can live on the planet.

There’s no exact timetable on the cooling process, which could eventually turn Earth solid, similar to Mars. But results from a new study, published in the peer-reviewed journal Earth and Planetary Science Letters, focuses on how quickly the core may cool by studying bridgmanite, a heat-conducting mineral commonly found at the boundary between the Earth’s core and mantle.

“Our results could give us a new perspective on the evolution of the Earth’s dynamics,”  ETH Zurich professor Motohiko Murakami, the lead author of the study, said in a press release. “They suggest that Earth, like the other rocky planets Mercury and Mars, is cooling and becoming inactive much faster than expected.”

While the process may be moving quicker than previously thought, it’s a timeline that “should be hundreds of millions or even billions of years,” Murakami told USA TODAY.

The boundary between the Earth’s outer core and mantle is where the planet’s internal heat interaction exists. The scientific team studied how much bridgmanite conducts from the Earth’s core and found higher heat flow is coming from the core into the mantle, dissipating the overall heat and cooling much faster than initially thought. 

“This measurement system let us show that the thermal conductivity of bridgmanite is about 1.5 times higher than assumed,” Murakami said in the press release. “We still don’t know enough about these kinds of events to pin down their timing.”

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