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Scientists determine age of youngest known Homo erectus remains – CTV News

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NEW YORK —
Scientists say they have finally calculated the age of the youngest known remains of Homo erectus, which is generally considered an ancestor of our species.

The fossilized skull fragments and other bones were uncovered on the Indonesian island of Java in the 1930s. Determining their age has been a scientific challenge, and a wide range has been proposed by numerous studies.

In a report released Wednesday by the journal Nature, scientists conclude the remains are between 108,000 and 117,000 years old. Researchers used five dating techniques on sediments and fossil animal bones from the area, combining 52 age estimates for the analysis. The project took 13 years to complete.

“I don’t see any way to date this site more thoroughly,” said paleoanthropologist Russell Ciochon of the University of Iowa, an author of the study.

H. erectus arose in Africa about 2 million years ago and spread widely there and in Asia, and possibly into Europe. It reached Java more than 1.5 million years ago, and the new dates suggest it died out at least 35,000 years before the arrival there of our own species, Homo sapiens.

H. erectus may have been doomed on Java by climate change that turned its open woodland environment into rain forest, Ciochon said. Still, it evidently existed longer on Earth than any other species on our “Homo” branch of the evolutionary tree.

Susan Anton, a New York University anthropologist who did not participate in the work, called the dating effort “heroic.” But she said she considered the reported age range to be too narrow. She said she preferred a span of less than 550,000 years old to more than 100,000 years old.

That’s roughly what she and co-authors proposed in a paper published in 2011. The younger end of the range in that paper was as recent as 120,000 years, which she said is virtually the same as the new result.

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Is there really life on Venus? How do we find out? – HalifaxToday.ca

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Last week, an unlikely research project made a startling discovery: Phosphine gas in the atmosphere of Venus. That’s something that, as far as we know, is created by living organisms. Our efforts to find signs of life on other worlds, and a lot of our space dreaming in general, tend to focus on Mars. But all of a sudden we need to take a closer look at our other planetary neighbour.

So how can we find out if there’s really life right next door? What do we know about Venus and why has it been so hard to figure out so far? What else could possibly cause the presence of Phosphine and what would it mean, to space exploration and everything else, if this is really true?

GUEST: Neel Patel, space reporter, MIT Technology Review

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The 'Red Planet' approaches – Coast Reporter

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This summer has been pretty interesting with Comet NEOWISE, the Perseids and some close lunar/planetary appulses in September. (Yes, it’s my new vocabulary word of the month.) October, however, is all about Mars – but the COVID-19 threat we’re facing limits our options somewhat. 

Opposition occurs when Earth passes between the sun and a celestial object – they’re opposite to each other in the sky. Because of our orbital periods – 365 days for Earth and 780 earth days for Mars – a Mars opposition happens about every 26 months. However, the accompanying composite of Hubble images from previous oppositions illustrates that there’s more to it than just that. For example, although opposition is Oct. 13, we’re actually slightly closer on Oct. 6. 

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First, neither planet has a circular orbit; Earth’s is slightly elliptical and Mars’ is much more so. Hence, the close approach distance varies according to how close or far from the Sun each planet is. Second, Earth and Mars orbit in slightly different planes; Mars can be above or below the plane of Earth’s orbit and therefore a bit further away. As well, Mercury and Venus slightly affect Earth’s orbit and Jupiter affects everything, so all the orbits change slowly over time. Finally, we’re in the northern hemisphere; a near-winter opposition puts Mars much higher in the sky at night and we look through much less atmosphere. Although Mars isn’t quite as close as it was in July 2018, it will be about 30 degrees higher – better seeing. 

The Astronomy Picture of the Day site (APOD) at https://apod.nasa.gov/apod/ for Sept. 11 has a striking photo of Mars emerging from behind the Moon taken on Sept. 6 from Brazil, one of five occultations this year. The photo, lovely as it is, illustrates the problem of viewing Mars for most of us: you need a telescope. While you can see Jupiter as a small disc and four moons with good binoculars and a tripod, Mars at its best is only a third that size. Without the current pandemic, I’m sure the Sechelt observatory would be open to the public for this opposition and people could stare to their hearts’ content, but at this point it doesn’t look good. Any changes will be posted on the club website. 

As in September, Jupiter and Saturn are low in the south after sunset, after their opposition in late July. The New Moon on the 16th coincides with its perigee (large tides) and it will pass Jupiter and Saturn a week later on the 22nd and 23rd. Interestingly, it will be a Full Moon on the 1st AND the 31st. 

Remember, all of the movements of moon and planets described can be checked out on the web at: www.heavens-above.com. The next regular meeting of the Astronomy Club should be Oct. 9 at 7 p.m. using Zoom. Information on the speaker and topic and how to register for the meeting will be on the club website at https://sunshinecoastastronomy.wordpress.com/ the week of the meeting.

– Richard Corbet

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Asteroid size of a bus comes close to Earth – Sierra Leone Times

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Scientists at the U.S. space agency NASA say a small asteroid – roughly the size of a bus – passed close to Earth on Thursday, flying just 22,000 kilometers above the surface, within the orbit of geostationary satellites that ring the planet.

While the proximity to Earth might raise alarm, scientists at NASA’s Jet Propulsion Laboratory (JPL) in Southern California said even if the asteroid had entered the earth’s atmosphere, it almost certainly would have broken up and become a bright meteor.

The asteroid, known as 2020 SW, is about five to ten meters wide and was first discovered on September 18 by the NASA-funded Catalina Sky Survey in Arizona.

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NASA’s Center for Near-Earth Object Studies (CNEOS) — part of the JPL — then did follow-up observations and confirmed its orbital trajectory, ruling out any chance of impact.

CNEOS director Paul Chodas says an object this size, this close to earth, is not uncommon. He says, “In fact, asteroids of this size impact our atmosphere at an average rate of about once every year or two.”

After passing the Earth, the asteroid will continue its journey around the Sun, not returning to Earth’s vicinity until 2041, when NASA says it will make a much more distant flyby.

The space agency says they believe there are over 100 million small asteroids like 2020 SW, but they are hard to discover unless they get very close to Earth.

In 2005, Congress assigned NASA the goal of finding 90 percent of the near-Earth asteroids that are about 140 meters or larger in size. These larger asteroids pose a much greater threat if they were to impact, and they can be detected much farther away from Earth, because they’re simply much brighter than the small ones.

Chodas says NASA’s asteroid surveys are getting better all the time, and the agency now expects to find asteroids the size of 2020 SW a few days before they come near Earth.

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