adplus-dvertising
Connect with us

Science

A Green Glow Has Been Detected in the Martian Atmosphere – Gizmodo

Published

 on


Artist’s impression of ESA’s ExoMars Trace Gas Orbiter detecting the green glow of oxygen in the martian atmosphere.
Image: ESA

The Red Planet has a touch of green, according to atmospheric observations performed by the ExoMars Trace Gas Orbiter. It’s the first time this effect has been documented on a planet other than Earth.

Advertisement

Like Earth, Mars features green airglow emissions in its dayside atmosphere, according to new research published in Nature Astronomy. The green hue happens when the Sun’s rays excite oxygen molecules in the upper atmosphere.

300x250x1

This green glow effect is quite faint, but astronauts aboard the International Space Station have the best seats in the house to view the phenomenon happening on Earth. They can spot airglow when looking at Earth’s limb—the curved edge of the planet as it appears to intersect with space.

Advertisement

Green airglow in Earth’s atmosphere, as seen from the ISS in 2011.

Green airglow in Earth’s atmosphere, as seen from the ISS in 2011.
Image: NASA

Airglow green line emissions are not to be confused with auroras, commonly known as the Northern and Southern Lights. Auroras arise from collisions between atmospheric molecules, namely oxygen and nitrogen, and fast-moving particles, i.e. electrons, that originate in Earth’s magnetic field. Green line emissions also involve oxygen atoms, which produce the green hue, but the dayglow happens when the Sun’s rays directly excite these atoms and molecules (Mars lacks a strong magnetic field). Nightglow emissions happen when busted molecules recombine.

And yes, Mars has oxygen, though not at the same levels seen on Earth. In fact, atmospheric oxygen on Mars exists as a byproduct of disintegrating carbon dioxide, the result of the Sun’s rays knocking out one of its two oxygen atoms. It’s this very process that produces the green glow, according to the new research, led by Jean-Claude Gérard of the University of Liège in Belgium.

Green airglow emissions on Mars were predicted to exist 40 years ago, but this is the first confirmed detection—a result made possible by the ExoMars Trace Gas Orbiter, a satellite that’s been circling Mars since 2016. The orbiter detected the excited oxygen with its NOMAD spectrometer, which scanned the Martian dayside surface in both ultraviolet and visible light.

Advertisement

“Previous observations hadn’t captured any kind of green glow at Mars, so we decided to reorient the [ultraviolet and visible spectrometer]… to point at the ‘edge’ of Mars, similar to the perspective you see in images of Earth taken from the ISS,” explained Ann Carine Vandaele from the the Royal Belgian Institute for Space Aeronomy in an ESA press release.

The researchers took measurements between 12 to 250 miles (20 to 400 km) above the Martian surface. The green oxygen emissions were found in all of these altitudes, but they were strongest at 50 miles (80 km) above the surface. The strength varied according to the changing distance between Mars and the Sun.

Advertisement

Interestingly, this technique can now be used to measure the density of the Martian atmosphere. This could prove useful for upcoming missions in which engineers need to account for the atmospheric drag experienced by orbiting satellites and by parachutes delivering probes to the surface.

Earth and Venus, as seen from the surface of Mars.

Earth and Venus, as seen from the surface of Mars.
Image: NASA/JPL-Caltech

Advertisement

In other Mars-related news, NASA’s Curiosity rover captured a shot of Earth and Venus in the Martian night sky. Both planets appear as bright specks of light, with the third planet from the Sun glowing more brightly than the second, as seen from the fourth planet. The image was captured on June 5, 2020 as Curiosity was measuring the brightness of twilight.

Let’s block ads! (Why?)

728x90x4

Source link

Continue Reading

Science

Giant prehistoric salmon had tusk-like teeth for defence, building nests: study – Times Colonist

Published

 on


The artwork and publicity materials showcasing a giant salmon that lived five million years ago were ready to go to promote a new exhibit, when the discovery of two fossilized skulls immediately changed what researchers knew about the fish.

Initial fossil discoveries of the 2.7-metre-long salmon in Oregon in the 1970s were incomplete and had led researchers to mistakenly suggest the fish had fang-like teeth.

It was dubbed the “sabre-toothed salmon” and became a kind of mascot for the Museum of Natural and Cultural History at the University of Oregon, says researcher Edward Davis.

300x250x1

But then came discovery of two skulls in 2014.

Davis, a member of the team that found the skulls, says it wasn’t until they got back to the lab that he realized the significance of the discovery that has led to the renaming of the fish in a new, peer-reviewed study.

“There were these two skulls staring at me with sideways teeth,” says Davis, an associate professor in the department of earth sciences at the university.

In that position, the tusk-like teeth could not have been used for biting, he says.

“That was definitely a surprising moment,” says Davis, who serves as director of the Condon Fossil Collection at the university’s Museum of Natural and Cultural History.

“I realized that all of the artwork and all of the publicity materials and bumper stickers and buttons and T-shirts we had just made two months prior, for the new exhibit, were all out of date,” he says with a laugh.

Davis is co-author of the new study in the journal PLOS One, which renames the giant fish the “spike-toothed salmon.”

It says the salmon used the tusk-like spikes for building nests to spawn, and as defence mechanisms against predators and other salmon.

The salmon lived about five million years ago at a time when Earth was transitioning from warmer to relatively cooler conditions, Davis says.

It’s hard to know exactly why the relatives of today’s sockeye went extinct, but Davis says the cooler conditions would have affected the productivity of the Pacific Ocean and the amount of rain feeding rivers that served as their spawning areas.

Another co-author, Brian Sidlauskas, says a fish the size of the spike-toothed salmon must have been targeted by predators such as killer whales or sharks.

“I like to think … it’s almost like a sledgehammer, these salmon swinging their head back and forth in order to fend off things that might want to feast on them,” he says.

Sidlauskas says analysis by the lead author of the paper, Kerin Claeson, found both male and female salmon had the “multi-functional” spike-tooth feature. 

“That’s part of our reason for hypothesizing that this tooth is multi-functional … It could easily be for digging out nests,” he says.

“Think about how big the (nest) would have to be for an animal of this size, and then carving it out in what’s probably pretty shallow water; and so having an extra digging tool attached to your head could be really useful.”

Sidlauskas says the giant salmon help researchers understand the boundaries of what’s possible with the evolution of salmon, but they also capture the human imagination and a sense of wonder about what’s possible on Earth.

“I think it helps us value a little more what we do still have, or I hope that it does. That animal is no longer with us, but it is a product of the same biosphere that sustains us.”

This report by The Canadian Press was first published April 24, 2024.

Brenna Owen, The Canadian Press

Adblock test (Why?)

728x90x4

Source link

Continue Reading

Science

Giant prehistoric salmon had tusk-like spikes used for defence, building nests: study

Published

 on

A new paper says a giant salmon that lived five million years ago in the coastal waters of the Pacific Northwest used tusk-like spikes as defense mechanisms and for building nests to spawn.

The initial fossil discoveries of the 2.7-metre-long salmon in Oregon in the 1970s were incomplete and led researchers to suggest the fish had fang-like teeth.

The now-extinct fish was dubbed the “saber-tooth salmon,” but the study published in the peer-reviewed journal PLOS One today renames it the “spike-toothed salmon” and says both males and females possessed the “multifunctional” feature.

Study co-author Edward Davis says the revelation about the tusk-like teeth came after the discovery of fossilized skulls at a site in Oregon in 2014.

300x250x1

Davis, an associate professor in the department of earth sciences at the University of Oregon, says he was surprised to see the skulls had “sideways teeth.”

Contrary to the belief since the 1970s, he says the teeth couldn’t have been used for any kind of biting.

“That was definitely a surprising moment,” Davis says of the fossil discovery in 2014. “I realized that all of the artwork and all of the publicity materials … we had just made two months prior, for the new exhibit, were all out of date.”

Adblock test (Why?)

728x90x4

Source link

Continue Reading

Science

SpaceX sends 23 Starlink satellites into low-Earth orbit

Published

 on

April 23 (UPI) — SpaceX launched 23 Starlink satellites into low-Earth orbit Tuesday evening from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida.

Liftoff occurred at 6:17 EDT with a SpaceX Falcon 9 rocket sending the payload of 23 Starlink satellites into orbit.

The Falcon 9 rocket’s first-stage booster landed on an autonomous drone ship in the Atlantic Ocean after separating from the rocket’s second stage and its payload.

The entire mission was scheduled to take about an hour and 5 minutes to complete from launch to satellite deployment.

300x250x1

The mission was the ninth flight for the first-stage booster that previously completed five Starlink satellite-deployment missions and three other missions.

Adblock test (Why?)

728x90x4

Source link

Continue Reading

Trending