Ice in the Air Makes Earth Sparkle From Space

NASA
NASA

A satellite orbiting Earth has captured images of our planet seemingly studded with flecks of gold glitter—the result, scientists say, of sunlight reflecting off ice particles in our atmosphere. They published their findings in the journal Geophysical Research Letters.

Alexander Marshak helps direct the Deep Space Climate Observatory (DSCOVR), a joint venture between NASA and NOAA. Tucked aboard that observatory is an instrument called EPIC, or the Earth Polychromatic Imaging Camera. As DSCOVR passes between Earth and the Sun, EPIC takes photo after photo, like a proud parent on prom night.

And just like an eager teen dressed for the dance, our planet is apparently just decked out in sparkles.

Astronomers have known about the little gold flashes of light for decades; legendary cosmos-gazer Carl Sagan even described them in a journal article three years before his death. In reviewing images from the Galileo telescope, Sagan and his colleagues developed a reasonable theory: The flashes were the ordinary reflections of sunlight bouncing off flat stretches of the ocean. After all, they said, there were no flashes over land.

But there were. Marshak and his colleagues first noticed a few tiny glints over landmasses in EPIC’s images. Then they went back to Galileo’s snapshots and found even more.


An image from the EPIC instrument aboard DSCOVR, taken on Dec. 3, 2015, shows a glint over central South America (circled in red).
NASA/NOAA/U.S. Air Force.

“When I first saw [a small flash] I thought maybe there was some water there,” Marshak said in a statement, “or a lake the sun reflects off of. But the glint is pretty big, so it wasn’t that.”

The flashes are also too big, and too significantly positioned relative to the Sun, to be the result of electric storms. “Lightning doesn’t care about the sun and EPIC’s location,” Marshak said, and “The source of the flashes is definitely not on the ground.”

That leaves only our atmosphere, which is sprinkled with a layer of fine ice particles. When the ice particles are floating horizontally and the Sun hits them just right, those particles coruscate better than a tiara under a disco ball.

And while Earth will always be the prom queen of our hearts, Marshak says we may not be the only bedazzled planet out there; in the future, researchers may be able to use these flashes to study exoplanets.

No Venom, No Problem: This Spider Uses a Slingshot to Catch Prey

Courtesy of Sarah Han
Courtesy of Sarah Han

There are thousands of ways nature can kill, and spider species often come up with the most creative methods of execution. Hyptiotes cavatus, otherwise known as the triangle weaver spider, is one such example. Lacking venom, the spider manages to weaponize its silk, using it to hurl itself forward like a terrifying slingshot to trap its prey.

This unusual method was studied up close for a recent paper published in the Proceedings of the National Academy of Sciences by researchers at the University of Akron in Ohio. They say it's the only known instance of an animal using an external device—its web—for power amplification.

Hyptiotes cavatus's technique is simple. After constructing a web, the spider takes one of the main strands and breaks it in half, pulling it taut by moving backwards. Then, it anchors itself to a spot with more webbing in the rear. When the spider releases that webbing, it surges forward, propelled by the sudden release of stored energy. In the slingshot analogy, the webbing is the strap and the spider is the projectile.

This jerking motion causes the web to oscillate, tangling the spider's prey further in silk. The spider can repeat this until the web has completely immobilized its prey, a low-risk entrapment that doesn’t require the spider to get too close and risk injury from larger victims.

The triangle weaver spider doesn’t have venom, and it needs to be proactive in attacking and stifling prey. Once a potential meal lands in its web, it’s able to clear distances much more quickly using this slingshot technique than if it crawled over. In the lab, scientists clocked the spider’s acceleration at 2535 feet per second squared.

Spiders are notoriously nimble and devious. Cebrennus rechenbergi, or the flic-flac spider, can do cartwheels to spin out of danger; Myrmarachne resemble ants and even wiggle their front legs like ant antennae. It helps them avoid predators, but if they see a meal, they’ll drop the act and pounce. With H. cavatus, it now appears they’re learning to use tools, too.

[h/t Live Science]

Bad News: The Best Time of the Day to Drink Coffee Isn’t as Soon as You Wake Up

iStock.com/ThomasVogel
iStock.com/ThomasVogel

If you depend on coffee to help get you through the day, you can rest assured that you’re not the world's only caffeine fiend. Far from it. According to a 2018 survey, 64 percent of Americans said they had consumed coffee the previous day—the highest percentage seen since 2012.

While we’re collectively grinding more beans, brewing more pots, and patronizing our local coffee shops with increased frequency, we might not be maximizing the health and energy-boosting benefits of our daily cup of joe. According to Inc., an analysis of 127 scientific studies highlighted the many benefits of drinking coffee, from a longer average life span to a reduced risk for cancer, heart disease, type 2 diabetes, and Parkinson’s disease.

Sounds great, right? The only problem is that the benefits of coffee might be diminished depending on the time of day that you drink it. Essentially, science tells us that it’s best to drink coffee when your body’s cortisol levels are low. That’s because both caffeine and cortisol cause a stress response in your body, and too much stress is bad for your health for obvious reasons. In addition, it might end up making you more tired in the long run.

Cortisol, a stress hormone, is released in accordance with your circadian rhythms. This varies from person to person, but in general, someone who wakes up at 6:30 a.m. would see their cortisol levels peak in different windows, including 8 to 9 a.m., noon to 1 p.m., and 5:30 to 6:30 p.m. Someone who rises at 10 a.m. would experience cortisol spikes roughly three hours later, and ultra-early risers can expect to push this schedule three hours forward.

However, these cortisol levels start to rise as soon as you start moving in the morning, so it isn’t an ideal time to drink coffee. Neither is the afternoon, because doing so could make it more difficult to fall asleep at night. This means that people who wake up at 6:30 a.m. should drink coffee after that first cortisol window closes—roughly between 9:30 a.m. and 11:30 a.m.—if they want to benefit for a little caffeine jolt.

To put it simply: "I would say that mid-morning or early afternoon is probably the best time," certified dietitian-nutritionist Lisa Lisiewski told CNBC. "That's when your cortisol levels are at their lowest and you actually benefit from the stimulant itself."

[h/t Inc.]

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