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How low did it go? Scientists calculate Earth's Ice Age temperatures – CBC.ca

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Guided by ocean plankton fossils and climate models, scientists have calculated just how cold it got on Earth during the depths of the last Ice Age, when immense ice sheets covered large parts of North America, South America, Europe and Asia.

The average global temperature during the period known as the Last Glacial Maximum from roughly 23,000 to 19,000 years ago was about 7.8 C, some 7 C colder than 2019, the researchers said on Wednesday.

Certain regions were much cooler than the global average, they found. The polar regions cooled far more than the tropics, with the Arctic region 14 C colder than the global average.

This global map shows the temperature differences compared to preindustrial times. Dark blue translates to cooler temperatures. The ice sheets of the past are superimposed on the continents. (Jessica Tierney/University of Arizona)

The researchers made their calculations with the aid of chemical measurements on tiny fossils of zooplankton and the preserved structures of fats from other types of plankton that change in response to water temperature — what they called a “temperature proxy.”

This information was then plugged into climate model simulations to calculate average global temperatures.

“Past climates are the only information we have about what really happens when the Earth cools or warms to a large degree. So by studying them, we can better constrain what to expect in the future,” said University of Arizona paleoclimatologist Jessica Tierney, lead author of the research published in the journal Nature.

During the Ice Age, which lasted from about 115,000 to 11,000 years ago, large mammals well adapted to a cold climate such as the mammoths, mastodons, woolly rhinos and sabre-toothed cats roamed the landscape.

Humans entered North America for the first time during the Ice Age, crossing a land bridge that once connected Siberia to Alaska with sea levels much lower than they are today.

Sabre-toothed cat skeleton on display in the Royal Ontario Museum’s Reed Gallery of the Age of Mammals. During the Ice Age, which lasted from about 115,000 to 11,000 years ago, large mammals well adapted to a cold climate roamed the landscape. (Wanda Dobrowlanski/Royal Ontario Museum)

Human hunting is believed to have contributed to mass extinctions globally of many species at the end of the Ice Age.

“What is interesting is that Alaska was not entirely covered with ice,” Tierney said. “There was an ice-free corridor that allowed humans to travel across the Bering Strait, into Alaska. Central Alaska was actually not that much colder than today, so for Ice Age humans it might have been a relatively nice place to settle.”

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‘Mini-moon’ set to join Earth might be a rock — or something more – Global News

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Earth and the moon have had a pretty steady relationship over the last 4.53 billion years, but our planet is about to have a close encounter with another body in space, according to astronomers’ projections.

A small object is expected to fall into Earth’s orbit in October, when it will potentially become a so-called “mini-moon” for the next several months. The new object, dubbed 2020 SO, will loop around the Earth in a figure-eight before spinning back into space in May 2021, according to NASA tracking data. The space agency has dubbed it an Apollo object, meaning it’s expected to cross Earth’s orbit.

Read more:
They shall call it ‘mini-moon’ — car-sized object found orbiting Earth

Most space objects are asteroids, but astronomers say there’s something unusual about this one. They say it’s no mini-moon — it’s a piece of space trash. More specifically, it might be a discarded Centaur rocket booster from the Surveyor 2 robot that crash-landed on the moon in September 1966.

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Whatever it is, it could become the second mini-moon in Earth’s orbit this year after 2020 CD3, a car-sized bit of space rock, left us in February. That mini-moon quietly circled Earth for about two years, though astronomers didn’t spot it until shortly before it left.

This one is on course to become a mini-moon but it has a “highly chaotic path,” according to Tony Dunn, who runs the website Orbit Simulator.

Mini-moons are extremely rare despite our luck with them this year. Earth’s gravity will typically pull a space rock down as a meteor or bend its trajectory before releasing it into space. However, space objects can do a few loops around our planet if they approach it just right.

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That’s what happened with 2020 CD3 earlier this year. Earth also hooked up with another asteroid, dubbed 2006 RH120, for a brief mini-moon fling through space 14 years ago.

There’s still no guarantee that the object will become a mini-moon, as Lisa Harvey-Smith, an astrophysicist with the Australian government, pointed out on Twitter.






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India loses contact with space craft heading for moon


India loses contact with space craft heading for moon

The object is expected to come within 50,000 kilometres of Earth on its first pass, and within 220,000 kilometres for its second close encounter. Both passes will bring it closer to Earth than the moon.

This object would become our third mini-moon in recent memory — and perhaps the first one made by humans.

The strongest indicator that it’s not an asteroid is the low velocity, according to Alice Gorman, a space archaeologist at Flinders University in Australia.

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“What I’m seeing is that it’s just moving too slowly, which reflects its initial velocity,” she told ScienceAlert. “That’s essentially a big giveaway.”

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The object is between 6.4 and 14 metres long, according to NASA.

The Centaur rocket booster was 12.68 metres long, and it helped propel the Surveyor 2 lander to the moon exactly 54 years ago. The lander jettisoned the booster into space during the mission.

This 1963 photograph shows vent flowing cryogenic fuel and T/C Rake mounted on a 1/10 scale model Centaur rocket in the Supersonic Wind Tunnel at the Glenn Research Center.


This 1963 photograph shows vent flowing cryogenic fuel and T/C Rake mounted on a 1/10 scale model Centaur rocket in the Supersonic Wind Tunnel at the Glenn Research Center.


NASA

Gorman says that if it is an old piece of human technology, she’d like to scan it to see how much damage it’s sustained after half a century in space.

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“It’s human material that’s been out in a different part of space,” she said.

“It would be interesting to compare that to the results you get from stuff in low Earth orbit, which is much, much denser material.”

The object is expected to approach Earth on Oct. 1.

© 2020 Global News, a division of Corus Entertainment Inc.

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'Minimoon' approaching Earth may be 'space junk' from 1966 rocket launch – CTV News

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TORONTO —
A small asteroid that scientists project could orbit Earth until next spring might actually just be “space junk” more than half a century old.

The new object spotted by astronomers last week and dubbed 2020 SO, a provisional designation based on the discovery date, is expected to fall into our orbit, where it will spin from mid-October to May 2021.

If it doesn’t change course, it could be the third object — sometimes referred to as “minimoons” — confirmed by scientists to be captured in Earth’s celestial path, according to news site ScienceAlert. In 2006, asteroid 2006 RH120 orbited with Earth for about nine months, and in 2020, scientists realized that a rock called 2020 CD3 had been orbiting for three years already.

Though it is still unclear whether 2020 SO is a small asteroid or a man-made object, one NASA scientist with the Jet Propulsion Laboratory in Southern California has “tentatively identified” it as a piece from the failed Surveyor 2 moon lander program in 1966. At the time, NASA used “multi-stage” rockets, some parts of which would fall back to the ground for reuse while others would be discarded in space. 

According to a member of the The Minor Planet Mailing List, an online group of space enthusiasts and lunar researchers, the velocity projections of the object suggest “it is unlikely it is a natural body” and that is is “more likely space junk.”

Current estimates put the size of the object between roughly six and 14 metres in length, which is consistent with the size of the 1966 rocket piece NASA identified, according to ScienceAlert. 

It won’t get very close and is on a “highly-chaotic path,” wrote orbit simulator Tony Dunn on Twitter. In fact, projections suggest it will pass by Earth on Dec. 1 at a distance of about 50,000 kilometres, and later in February at about 220,000 kilometres.

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Earth is about to capture a new “mini moon” (but it might not be a moon at all) – Yahoo Canada Sports

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The March 5 _mini-Moon,î the apogee Moon, the most distant Full Moon of 2015. I processed this image with greatly enhanced vibrance, saturation and contrast to exaggerate the subtle differences in colour in the lunar maria, due to differences in the mineral content of the lava flows that formed the mare ~3.5 to 4 billion years ago. The relatively new impact crater, Tycho, is the bright area at bottom (south) on the luanr disk with bright splash rays emanating from the crater. I shot this with a TMB 92mm refractor with a 2x Barlow lens for an effective f-ratio of about f/12. This is a 1/125th second exposure at ISO100 with the Canon 60Da. (Photo by: Alan Dyer /VW PICS/Universal Images Group via Getty Images)

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From October, Earth will have another, much smaller, moon (Photo by: Alan Dyer /VW PICS/Universal Images Group via Getty Images)
<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="A new mini-moon might be about to join Earth’s orbit briefly, before being hurled back into space.” data-reactid=”32″>A new mini-moon might be about to join Earth’s orbit briefly, before being hurled back into space.

‘Minimoons’ are only a few feet across, and each tends to do a stint of around a few months in orbit – before resuming their previous lives as asteroids.

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="But this particular mini-moon may be a little different – as experts have suggested it’s not a moon at all, but man-made space junk.&nbsp;” data-reactid=”34″>But this particular mini-moon may be a little different – as experts have suggested it’s not a moon at all, but man-made space junk. 

Specifically, it may be a discarded part of a rocket launched in 1966, experts have suggested. 

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="The tiny object, known as 2020 SO, was spotted by the Pan-STARRS1 at the Haleakala Observatory on 17 September 2020, ScienceAlert reports.&nbsp;” data-reactid=”36″>The tiny object, known as 2020 SO, was spotted by the Pan-STARRS1 at the Haleakala Observatory on 17 September 2020, ScienceAlert reports

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Read more: What are fast radio bursts, and why do they look like aliens?” data-reactid=”37″>Read more: What are fast radio bursts, and why do they look like aliens?

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="It will be captured by Earth this October, and will pass close by Earth in December 2020 and February 2021, Sky reports.&nbsp;” data-reactid=”38″>It will be captured by Earth this October, and will pass close by Earth in December 2020 and February 2021, Sky reports

It will continue to orbit our planet until May next year. 

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Alice Gorman of Flinders University in Australia says that several measurements about 2020 SO suggest it’s not an asteroid, in an interview with Science Alert..&nbsp;” data-reactid=”40″>Alice Gorman of Flinders University in Australia says that several measurements about 2020 SO suggest it’s not an asteroid, in an interview with Science Alert.. 

Vent flowing cryogenic fuel and T/C Rake mounted on a 1/10 scale model Centaur in the l0 x l0 Foot Supersonic Wind Tunnel. The fuel being used is liquid hydrogen. The point of the test is to determine how far to expel venting fuel from the rocket body to prevent explosion at the base of the vehicle. This vent is used as a safety valve for the fumes created when loading the fuel tanks during launch preparation. Liquid hydrogen has to be kept at a very low temperature. As it heats, it turns to gas and increases pressure in the tank. It therefore has to be vented overboard while the rocket sits on the pad.Vent flowing cryogenic fuel and T/C Rake mounted on a 1/10 scale model Centaur in the l0 x l0 Foot Supersonic Wind Tunnel. The fuel being used is liquid hydrogen. The point of the test is to determine how far to expel venting fuel from the rocket body to prevent explosion at the base of the vehicle. This vent is used as a safety valve for the fumes created when loading the fuel tanks during launch preparation. Liquid hydrogen has to be kept at a very low temperature. As it heats, it turns to gas and increases pressure in the tank. It therefore has to be vented overboard while the rocket sits on the pad.

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A scale model of a Centaur rocket, used in the 1966 launch (Getty)

Gorman said, “The velocity seems to be a big one. What I’m seeing is that it’s just moving too slowly, which reflects its initial velocity. That’s essentially a big giveaway.”

Gorman says that these signs suggest that the object may be space junk. 

Astronomer Paul Chodas has suggested that teh object is a Surveyor 2 Centaur rocket body, launched on September 20, 1966. 

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Read more: Astronomers find closest black hole to Earth” data-reactid=”64″>Read more: Astronomers find closest black hole to Earth

Chodas suggests that the low Earth encounter velocity is too low even for material ejected from the moon, so it’s unlikely to be a natural body. 

Spectroscopy may be able to show if the object has been painted, the experts believe. 

Gorman says, “It would be interesting to do some reflectance spectroscopy, which would show how rough the surfaces are, how much it’s been pitted and decayed from being bombarded by dust and micro meteorites.”

“It’s human material that’s been out in a different part of space. So, it would be interesting to compare that to the results you get from stuff in low Earth orbit, which is much, much denser in material.”

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