Look Up! The Southern Delta Aquariids Meteor Shower Is Here

NASA/Bill Dunford
NASA/Bill Dunford

Wake a few hours before sunrise tomorrow and you can start your day with some shooting stars. The Southern Delta Aquariid meteor shower is peaking this week, and while it's not the brightest show of the year, conditions are good and the moonlight is minimal. Provided you live in an area lacking light pollution, you might be in for quite a treat.

Consider this shower to be the big warmup for the Perseids next month. You might even see a Perseid or two tonight (though it's not like they're labeled; just stick with probability when you tell everyone what you saw). So where did these meteors come from, and what's going on up there?


Comet Machholz recorded on March 1, 2005
Comet Machholz as recorded on March 1, 2005
NASA/JPL-Caltech/U. Washington/J. Morgenthaler

The Delta Aquariids are suspected to be the debris of 96P/Machholz, a sungrazing comet that orbits the Sun every 5.3 years. Sungrazers are the fighter pilots of the comet world, buzzing perilously close to the face of the Sun as they go about an orbit. Machholz is their Chuck Yeager. The comet's perihelion—that is, its point closest to the Sun in its orbit—is 0.1 astronomical unit. This puts it far closer to the Sun than Mercury, whose perihelion is 0.3 AU. (Earth is 1 AU.) When Machholz is at aphelion—its maximum distance away from the Sun—it reaches 5.9 AU, which is beyond even Jupiter's orbit.

It gets weirder yet. The comet's orbital inclination is 58 degrees. Rather than circle the Sun along the orbital plane of most planets (think of the light bulb and marble-on-wires model of the solar system from grade school), it is swooping up and away pretty dramatically. This adds up to a comet without fear, and as it goes about its orbit, it leaves behind a debris field of dust and sand-sized particles. That's where the Earth comes in. Every year as we travel our orbit, we cross through Machholz's trail, slamming into those particles at tens of thousands of miles per hour. When they burn up in our atmosphere, we get the stunning light show we call a meteor shower.


As the shower's name implies, its radius—the seeming point of origin in our night sky—is the constellation Aquarius. Don't limit yourself to looking specifically in that area, though; all the sky is a meteor's canvas. You should give your eyes 30 minutes to adjust to the darkness. Bring a blanket and scan about 45 degrees up from the horizon. That's where the most action will begin to be apparent. Good news if you live in the southern hemisphere (or if you live near the equator in the northern hemisphere): You will get the best viewing of anyone on Earth.

The meteors should be visible until sunrise. If you oversleep or the weather is bad, try again tomorrow night. This shower doesn't have a pronounced peak like others, and you have a fair chance of catching something if you stick with it in the days ahead. The next big meteor shower will be the Perseids, which will peak on the night of August 12.

The Leonid Meteor Shower Peaks This Weekend—Here's the Best Way to See It

NASA/Getty Images
NASA/Getty Images

The Leonid meteor shower will be making its annual appearance in the sky this weekend. As NPR reports, the best time to catch it will be late Saturday night into Sunday morning (November 17-18)—so if you really want to catch this dazzling light show, you may want to drink some coffee to help you stay up.

The waxing gibbous Moon will dull the meteors’ shine a little, so plan to start stargazing after the Moon has set but before dawn on Sunday. (You can use timeanddate.com to figure out the moonset time in your area. The site also features an interactive meteor shower sky map to track visibility conditions.)

If you'll be in parts of the South or Midwest this weekend, you're in luck. Florida, Alabama, Mississippi, Nebraska, and Nevada are expected to enjoy the best view of the Leonids this time around, according to Popular Mechanics.

The Leonids occur every year around November 17 or 18, when Earth drifts across the long trail of debris left behind by the comet Tempel-Tuttle. The comet takes 33 years to complete its orbit around the Sun, and when it reaches perihelion (its closest approach to the Sun), a Leonid storm may occur depending on the density of the comet's existing debris. This sometimes results in hundreds of thousand of meteors streaking across the sky per hour, viewable from Earth. The last Leonid storm occurred in 2001, but Earth may not see dense debris clouds until 2099, according to the American Meteor Society.

This year, if skies are clear and you can secure a secluded spot away from city lights, you might be able to see around 15 to 20 meteors per hour. They travel at 44 miles per second “and are considered to be some of the fastest meteors out there,” NASA says. They’re also known for their “fireballs”—explosions of light and color—which tend to last longer than a typical meteor streak.

[h/t NPR]

Two Harvard Scientists Suggest 'Oumuamua Could Be, Uh, an Alien Probe

ESO/M. Kornmesser
ESO/M. Kornmesser

An odd, cigar-shaped object has been stumping scientists ever since it zoomed into our solar system last year. Dubbed 'Oumuamua (pronounced oh-MOO-ah-MOO-ah), it was first seen through the Pan-STARRS 1 telescope in Hawaii in October 2017. 'Oumuamua moved at an unusually high speed and in a different kind of orbit than those of comets or asteroids, leading scientists to conclude that it didn't originate in our solar system. It was the first interstellar object to arrive from somewhere else, but its visit was brief. After being spotted over Chile and other locales, 'Oumuamua left last January, leaving lots of questions in its wake.

Now, two researchers at Harvard University bury a surprising suggestion in a new paper that analyzes the object's movement: 'Oumuamua could be an alien probe. Sure, why not?

First, astrophysicists Shmuel Bialy and Abraham Loeb argue that 'Oumuamua is being driven through space by solar radiation pressure, which could explain its uncharacteristic speed. But for that theory to work, they calculate that the object must be unusually thin. Bialy and Loeb then analyze how such a slender object might withstand collisions with dust and gases, and the force of rotation, on its interstellar journey.

Then things get weird.

"A more exotic scenario is that 'Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization," they write [PDF]. They suggest that ‘Oumuamua could be be a lightsail—an artificial object propelled by radiation pressure—which also happens to be the technology that the Breakthrough Starshot initiative, of which Loeb is the advisory committee chair, is trying to send into space. "Considering an artificial origin, one possibility is that 'Oumuamua is a lightsail, floating in interstellar space as a debris from an advanced technological equipment,” they write.

Their paper, which was not peer-reviewed, was posted on the pre-print platform arXiv.

Loeb is well known for theorizing about alien tech. He previously suggested that intense radio signals from 2007 could be the work of aliens who travel through space on solar sails. However, Loeb acknowledged that this theory deals more with possibility than probability, The Washington Post noted. “It’s worth putting ideas out there and letting the data be the judge,” Loeb told the paper last year.

[h/t CNN]