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Many of Mars’ stream valleys might have formed under an ice sheet – Ars Technica

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Enlarge / Examples of different types of valleys on Mars.

The further back into Earth’s history your mind wanders, the more work your imagination has to put in. That’s even more true for Mars. None of us have physically stepped foot on the present-day version of the planet, and its past was clearly very different from its present, with evidence pointing to flowing and standing water.

Among the relics of the watery past are networks of valleys incised into Mars’ surface. The Red Planet’s southern hemisphere highlands host many valleys, which have largely been interpreted as formed by rivers and groundwater springs. The source of water in rivers—whether rainfall in a warm climate or just melt from glacial ice—has been a question mark.

It’s thought that Mars’ past was generally quite cold, so a connection between the valleys and glacial ice is quite plausible. But how direct is that connection? We can identify the drainages in which water flows beneath ice sheets based on physical characteristics of the valleys left behind. So a team led by Anna Grau Galofre at Arizona State set out to analyze the valleys on Mars to see if any would better match a sub-glacial origin.

They worked with topographic data for over 10,000 valleys in almost 70 connected valley networks, characterizing each by a number of metrics. That includes some simple things, like valley width, the number of tributaries upstream, and the angle between connected channels. Another metric that turned out to be important is whether the valley undulates up and down a bit, or instead drops smoothly down-slope without interruption.

Combining all the metrics, the valleys fall into several clusters. There’s an indistinct area of overlap, meaning some valleys couldn’t be identified as one thing or another, but the others fell in line. Valley width, for example, is good at picking out valleys that are carved by glacial ice here on Earth. Simple channels with few tributaries indicate groundwater springs that trickle downhill. And sub-glacial drainage valleys tend to meet at angles closer to 90 degrees and undulate up and down—driven by high water pressure under a glacier.

Of the 66 networks of valleys, 18 couldn’t be identified and three looked like the result of groundwater springs. Only 14 were identifiable as formed by rivers. But nine valley networks had the characteristics of glacial erosion, and 22 fell under the sub-glacial drainage category.

To see if that made sense, the researchers compared the locations of the sub-glacial drainage valleys against a previously published ice sheet model. Glaciers and ice sheets have an upper, colder zone where snowfall accumulation dominates, and a lower, warmer zone where losses from melt or sublimation dominate. Sub-glacial drainages should exist in that lower zone, where meltwater is being produced. Laid out on a map, those 22 valley networks do generally sit in the region where the ice sheet model predicts they should—between the edge of the ice sheet and the “equilibrium line” that divides the melt zone from the accumulation zone.

These are the networks of valleys that were analyzed. (Sapping refers to groundwater springs.) The blue lines show a previous ice sheet model, with subglacial drainage valleys falling between the light blue and dark blue outlines.
These are the networks of valleys that were analyzed. (Sapping refers to groundwater springs.) The blue lines show a previous ice sheet model, with subglacial drainage valleys falling between the light blue and dark blue outlines.

The researchers think this ice sheet could have mostly been frozen to the ground, but with localized areas where friction or geothermal heat from below melted ice at the base. That would actually be a simple explanation for consistent sources of flowing water on a cold Mars, although it might paint an icier picture than the one you’ve had in your head.

“This picture alters the current understanding that all Martian valley networks originated by surface runoff and provides geomorphological support for the presence of ice sheets on early Mars,” the researchers write, “which reconciles climate predictions with observations from the geological record.”

Nature Geoscience, 2020. DOI: 10.1038/s41561-020-0618-x (About DOIs).

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COVID-19 messages may need to have greater impact – The Sudbury Star

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As the COVID-19 pandemic drags on, there’s a growing risk people may be tuning out information they need to know, says Dr. David Colby.

This undated transmission electron microscope image shows SARS-CoV-2, also known as novel coronavirus, the virus that causes COVID-19, isolated from a patient in the U.S. Virus particles are shown emerging from the surface of cells cultured in the lab. The spikes on the outer edge of the virus particles give coronaviruses their name, crown-like.

Photo supplied

As the COVID-19 pandemic drags on, there’s a growing risk people may be tuning out information they need to know, says Dr. David Colby.

“Higher-impact” messages may be necessary, said Chatham-Kent’s medical officer of health.

“There is such a thing as message fatigue as well,” Colby said. “Personally, I think it’s not a question of increasing the amount of education we’re doing but rather changing it up into a different style so that it refocuses peoples’ attention on the issues at hand.”

If people keep seeing the same message, eventually they no longer notice it, he said.

“Improvements can always be made,” Colby said. “We never want to get to the point where we basically sit back and say, ‘We’ve done it all. Let’s wait and see what happens.’

“We’re always searching to have a greater impact on people’s behaviour to the benefit of their health.”

The 401 new cases reported Friday in Ontario were the province’s highest single-day total since June 7 had 415 cases.

The numbers are better in Chatham-Kent, which reported no new cases for the sixth consecutive day Friday. The municipality’s cumulative total is 366 cases.

One more recovery raised Chatham-Kent’s total to 362. No one is hospitalized.

Active cases are down to two. Both stem from close contact with other cases.

There have been 25,756 individuals tested in Chatham-Kent.

“As the provincial numbers of new cases are increasing substantially, resulting in all this concern … we are not seeing that yet here,” Colby said, “but we will always be vigilant to deal with whatever comes our way, both in a reactive but especially a proactive way.”

The numbers were reversed in late July and early August. New cases were spiking in Chatham-Kent but sinking overall in the province.

“As our cases were going up, the provincial cases were going down sharply,” Colby said. “At a time when the (daily) number of new cases in the province was less than a hundred, that’s when we were dealing with our huge surge. We dealt with that. We are at a very, very low level now.”

Sarnia-Lambton has one active case, Middlesex-London has 53 active after 13 new cases were confirmed Friday, and Windsor-Essex County has 89 active cases.

Colby sympathizes with people suffering from pandemic fatigue.

“It’s difficult because people are tired of this, and none more than those on the front line that are dealing with it in public health,” he said. “It is very difficult.”

Anyone who says there’s no pandemic shouldn’t look to him for support.

“I have no idea how to deal with people that deny there’s a pandemic,” he said. “It’s sort of, to me, like people that deny that there are trees and rocks.”

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The detection of phosphine in Venus' clouds is a big deal – here's how we can find out if it's a sign of life – The Conversation US

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On Sept. 14, 2020, a new planet was added to the list of potentially habitable worlds in the Solar System: Venus.

Phosphine, a toxic gas made up of one phosphorus and three hydrogen atoms (PH₃), commonly produced by organic life forms but otherwise difficult to make on rocky planets, was discovered in the middle layer of the Venus atmosphere. This raises the tantalizing possibility that something is alive on our planetary neighbor. With this discovery, Venus joins the exalted ranks of Mars and the icy moons Enceladus and Europa among planetary bodies where life may once have existed, or perhaps might even still do so today.

I’m a planetary scientist and something of a Venus evangelical. This discovery is one of the most exciting made about Venus in a very long time — and opens up a new set of possibilities for further exploration in search of life in the Solar System.

Venus as seen in the infrared by the Japanese Akatsuki spacecraft. The warm colors are from the hot lower atmosphere glowing through the cooler cloud layers above. Image credit: JAXA/ISAS/DARTS/Damia Bouic.
JAXA/ISAS/DARTS/Damia Bouic

Atmospheric mysteries

First, it’s critical to point out that this detection does not mean that astronomers have found alien life in the clouds of Venus. Far from it, in fact.

Although the discovery team identified phosphine at Venus with two different telescopes, helping to confirm the initial detection, phosphine gas can result from several processes that are unrelated to life, such as lightning, meteor impacts or even volcanic activity.

However, the quantity of phosphine detected in the Venusian clouds seems to be far greater than those processes are capable of generating, allowing the team to rule out numerous inorganic possibilities. But our understanding of the chemistry of Venus’ atmosphere is sorely lacking: Only a handful of missions have plunged through the inhospitable, carbon dioxide-dominated atmosphere to take samples among the global layer of sulfuric acid clouds.

So we planetary scientists are faced with two possibilities: Either there is some sort of life in the Venus clouds, generating phosphine, or there is unexplained and unexpected chemistry taking place there. How do we find out which it is?

A model of the Soviet Vega 1 spacecraft at the Udvar-Hazy Center, Dulles International Airport. Vega 1 carried a balloon to Venus on its way to visit Halley’s Comet in 1985.
Daderot

First and foremost, we need more information about the abundance of PH₃ in the Venus atmosphere, and we can learn something about this from Earth. Just as the discovery team did, existing telescopes capable of detecting phosphine around Venus can be used for follow-up observations, to both definitively confirm the initial finding and figure out if the amount of PH₃ in the atmosphere changes with time. In parallel, there is now a huge opportunity to carry out lab work to better understand the types of chemical reactions that might be possible on Venus — for which we have very limited information at present.

Antennas of the Atacama Large Millimeter/submillimeter Array telescope, on the Chajnantor Plateau in the Chilean Andes. The telescope was used to confirm the initial detection of phosphine in Venus’ atmosphere.
ESO/C. Malin.

Once more unto the breach

But measurements on and from Earth can take us only so far. To really get to the heart of this mystery, we need to go back to Venus. Spacecraft equipped with spectrometers that can detect phosphine from orbit could be dispatched to the second planet with the express purpose of characterizing where, and how much, of this gas is there. Because spacecraft can survive for many years in Venus’ orbit, we could obtain continuous observations with a dedicated orbiter over a much longer period than with telescopes on Earth.

But even orbital data can’t tell us the whole story. To fully get a handle on what’s happening at Venus, we have to actually get into the atmosphere. And that’s where aerial platforms come in. Capable of operating above much of the acidic cloud layer – where the temperature and pressure are almost Earthlike – for potentially months at a time, balloons or flying wings could take detailed atmospheric composition measurements there. These craft could even carry the kinds of instruments being developed to look for life on Europa. At that point, humanity might finally be able to definitively tell if we share our Solar System with Venusian life.

A concept for an aerial platform at Venus. Two connected balloons could take turns to inflate, allowing the balloon to control the altitude at which it floats. An instrument package would then hang from below the balloons.
NASA/JPL-Caltech

A new dawn for Venus exploration?

Thirty-one years have elapsed since the United States last sent a dedicated mission to Venus. That could soon change as NASA considers two of four missions in the late 2020s targeting Venus. One, called VERITAS, would carry a powerful radar to peer through the thick clouds and return unprecedented high-resolution images of the surface. The other, DAVINCI+, would plunge through the atmosphere, sampling the air as it descended, perhaps even able to sniff any phosphine present. NASA plans to pick at least one mission in April 2021.

[Deep knowledge, daily. Sign up for The Conversation’s newsletter.]

I have argued before for a return to Venus, and will continue to do so. Even without this latest scientific discovery, Venus is a compelling exploration target, with tantalizing evidence that the planet once had oceans and perhaps even suffered a hellish fate at the hands of its own volcanic eruptions.

But with the detection of a potential biomarker in Venus’ atmosphere, we now have yet another major reason to return to the world ancient Greek astronomers called Phosphorus — a name for Venus that, it turns out, is wonderfully prescient.

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Municipalities look to Elon Musk for improved internet – Hanna Herald

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The Federation of Northern Ontario Municipalities’ board  of directors passed a resolution Sept. 15 in support of Starlink, Elon Musk’s satellite internet project.
Bill Pugliano/Getty Images


Sarah Cooke, Local Journalism Initiative

Internet access and remote/rural communities usually don’t go together well in a sentence, but Elon Musk’s satellite internet project  aims to fix that.
The Federation of Northern Ontario Municipalities’ board  of directors passed a resolution Sept. 15 in support of Starlink —  which is a low Earth orbit satellite system which can provide improved  upload/download speeds and response times for rural residents.
“We know today our citizens require greater connectivity than 50/10  megabits per second,” says Danny Whalen, president of FONOM. “FONOM  believes that the Starlink program is our best option.”
The resolution also calls on the Canadian Radio-Television and Telecommunications Commission (CRTC) to permit the company a basic international telecommunications service licence (BITS).
Space Exploration Technologies Corporation (SpaceX) is the parent company of Starlink and it applied for a BITS licence May 1.
On July 6, the CRTC published the procedural letter on  its website which states that it “received a number of  interventions, both in support of and in opposition” to SpaceX’s request  for a licence.
The letter further states that the CRTC provided SpaceX the opportunity to reply to these interventions.
The interventions and replies are available on the commission’s website under “closed BITS licenses.”
Discussions surrounding broadband and connectivity dominated much of  FONOM’s recent board meeting, according to a release issued Sept. 16.,  as the federation is looking to work with municipal organizations and  governments to bring improved internet services to its 110 communities.
SpaceX launched 180 satellites last month to grow the  “mega-constellation” and Starlink has allegedly begun private beta  testing.
A tweet from Musk on June 24 stated that, “Canada is a major priority for Starlink!”
Those interested in signing up for the potential to beta test Starlink can do so on the company’s website.
FONOM said it will not be communicating with its partners to seek additional support for the Starlink program.


Sarah Cooke is a Local Journalism Initiative reporter with muskokaregion.com. The Local Journalism Initiative is funded by the Government of Canada.

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