CLOSE
Kenneth Snyder, Flickr //  CC BY-NC-ND 2.0
Kenneth Snyder, Flickr // CC BY-NC-ND 2.0

Look Up! The Perseid Meteor Shower Peaks This Weekend

Kenneth Snyder, Flickr //  CC BY-NC-ND 2.0
Kenneth Snyder, Flickr // CC BY-NC-ND 2.0

Look up tonight and you’ll see streaks of light headed your way. The annual Perseid meteor shower has arrived, and if the skies are clear and light pollution low, you are in for quite a treat: This is easily the best meteor shower of the year. Those who stay up late (or wake really early) are virtually guaranteed to see something.

FROM SLAYER OF MEDUSA TO COMETARY DUST 

The Perseids are the result of a debris field left by the comet Swift-Tuttle. This is a Halley-type comet that orbits the Sun every 133 years. (Its highly eccentric orbit takes it far beyond Pluto in the meantime.) As the comet travels across the solar system, it leaves behind a trail of dust and sand-sized particles that, over the course of centuries and millennia, becomes an increasingly dense field. When the Earth's orbital path crosses this debris, the speed and force of our planet colliding into the comet's phantom particles vaporizes them. A distinctive "shooting star" is the result of energy released by a speck of cometary dust colliding with the atmosphere of a 3.7-octillion-mile celestial object—that would be Earth—moving at 67,000 miles per hour.

The Perseids get their name from the constellation from which they seem to originate: Perseus. Don’t limit yourself to staring at the celestial slayer of Medusa, however. (Though bonus points if you can actually find it.) Meteors will appear across the night sky. The shower was first formally "discovered" in 1835 by astronomer Adolphe Quételet, though it has been observed for millennia. Meteors near the shower’s peak are sometimes called the "tears of St. Lawrence," coinciding with the feast day of St. Lawrence of Rome.

KEEP AN EYE OUT FOR FIREBALLS

If you are in an area of low light pollution—that is, any remote area away from a city—you will be able to see between 30 and 40 meteors per hour this weekend. Believe it or not, that makes this a bad year for the Perseids shower, down from a possible 150 per hour. Many meteors will be obscured by the big bright Moon still riding high after reaching a full phase earlier this week.

To best experience a meteor shower, NASA recommends you dress for the lower temperatures that come at night and give your eyes a good 30 minutes to adjust to the darkness. Take a blanket outside, lay back, and take in the sky. Be on the lookout for fireballs, which are particularly bright meteors. (You'll know one when you see it.)

The best time to see the Perseids shower is between midnight and dawn on Saturday. If you miss the Perseids early Saturday morning due to bad weather (or just sleeping in), you can try again at the same time each early morning well into next week. If being outside just isn’t your thing, but astronomy is, you can also view the meteor shower online at Slooh, beginning at 8:00 p.m. EDT on Saturday. The Perseids are the perfect warmup for the main event later this month: a total solar eclipse over North America on August 21.

nextArticle.image_alt|e
iStock
arrow
Space
Mysterious 'Hypatia Stone' Is Like Nothing Else in Our Solar System
iStock
iStock

In 1996, Egyptian geologist Aly Barakat discovered a tiny, one-ounce stone in the eastern Sahara. Ever since, scientists have been trying to figure out where exactly the mysterious pebble originated. As Popular Mechanics reports, it probably wasn't anywhere near Earth. A new study in Geochimica et Cosmochimica Acta finds that the micro-compounds in the rock don't match anything we've ever found in our solar system.

Scientists have known for several years that the fragment, known as the Hypatia stone, was extraterrestrial in origin. But this new study finds that it's even weirder than we thought. Led by University of Johannesburg geologists, the research team performed mineral analyses on the microdiamond-studded rock that showed that it is made of matter that predates the existence of our Sun or any of the planets in the solar system. And, its chemical composition doesn't resemble anything we've found on Earth or in comets or meteorites we have studied.

Lead researcher Jan Kramers told Popular Mechanics that the rock was likely created in the early solar nebula, a giant cloud of homogenous interstellar dust from which the Sun and its planets formed. While some of the basic materials in the pebble are found on Earth—carbon, aluminum, iron, silicon—they exist in wildly different ratios than materials we've seen before. Researchers believe the rock's microscopic diamonds were created by the shock of the impact with Earth's atmosphere or crust.

"When Hypatia was first found to be extraterrestrial, it was a sensation, but these latest results are opening up even bigger questions about its origins," as study co-author Marco Andreoli said in a press release.

The study suggests the early solar nebula may not have been as homogenous as we thought. "If Hypatia itself is not presolar, [some of its chemical] features indicate that the solar nebula wasn't the same kind of dust everywhere—which starts tugging at the generally accepted view of the formation of our solar system," Kramer said.

The researchers plan to further probe the rock's origins, hopefully solving some of the puzzles this study has presented.

[h/t Popular Mechanics]

nextArticle.image_alt|e
NASA
arrow
science
The Ozone Layer Is Healing, Thanks to an International Ban on Harmful Man-Made Chemicals
NASA
NASA

The ozone layer is on the mend, thanks to a decrease in human-produced chemicals called chlorofluorocarbons, or CFCs, in the atmosphere. Using data from NASA's Aura satellite, scientists were able to measure the chemical composition of the thinned gas layer above the Antarctic and found about 20 percent less ozone depletion than there was in 2005. They published their findings on January 4 in the journal Geophysical Research Letters.

In 1985, UK scientists published a landmark study in the journal Nature announcing their discovery of an annually recurring hole in the ozone layer above Antarctica. (Each September, as the Southern Hemisphere's winter arrives, the Sun's UV rays trigger a reaction between the ozone and chemical elements from CFCs, chlorine and bromine, which destroys the ozone molecules.) The finding led to the Montreal Protocol in 1987, an international treaty that gradually banned the production and use of CFCs in refrigerants, aerosol sprays, solvents, and air conditioners.

In July 2016, Antarctic researchers published a study in the journal Science reporting that the ozone layer appeared to be healing (although it wasn't projected to completely patch up for decades). They tracked this progress by monitoring the Antarctic ozone hole's area, height, and chemical profile. Still, they didn't know whether this progress could be attributed to the Montreal Protocol's mandate.

NASA itself has used Aura to monitor the hole since the mid-2000s. After analyzing data produced by the Microwave Limb Sounder, a satellite instrument aboard Aura that measures trace gases, the space agency has confirmed that the CFC ban has led to the big decrease in ozone depletion during the Antarctic winter.

By winter, ozone-busting chlorine compounds have converted into hydrochloric acid, a process that occurs after it's destroyed ozone particles and reacts with methane. "By around mid-October, all the chlorine compounds are conveniently converted into one gas, so by measuring hydrochloric acid, we have a good measurement of the total chlorine," researcher Susan Strahan said in a NASA statement. Scientists compared these hydrochloric acid levels with nitrous oxide, which is similar in nature to CFCs but isn't diminishing in the atmosphere.

Their study is billed as "the first to use measurements of the chemical composition inside the ozone hole to confirm that not only is ozone depletion decreasing, but that the decrease is caused by the decline in CFCs," according to NASA. But while these initial results are promising, scientists say that the ozone layer's full recovery is still a long way off.

"As far as the ozone hole being gone, we're looking at 2060 or 2080,” study co-author Anne Douglass said. “And even then there might still be a small hole."

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios