The Perseid Meteor Shower Is Going to Be Amazing This Weekend

Bill Ingalls, NASA/Getty Images
Bill Ingalls, NASA/Getty Images

If you have camping plans this weekend, you’re in luck. The annual Perseid meteor shower will be returning August 10–13, and it’s expected to be the best and brightest one in years, astrophysicist Ethan Siegel writes for Forbes.

The Perseid meteor shower—named after the Perseus constellation, where the meteors originate—occurs every August when the Earth passes through a path of debris left by the Swift-Tuttle comet. This comet orbits the Sun once every 133 years, and in doing so, the intense heat and tidal forces cause parts of the comet to break off, creating a floating field of debris. The dust and particles left behind compose a comet's two tails: the ion tail and the dust tail.

According to Siegel, a few factors determine how spectacular a meteor shower will be, including light pollution conditions, how close Earth gets to the center of the debris stream, the relative speed of the debris to Earth, and the stream's density. Plus, the new moon phase on August 11 guarantees a darker sky. For this reason, Saturday night should be the best time to head outside and look up.

"The Moon is very favorable for the Perseids this year, and that'll make the Perseids probably the best shower of 2018 for people who want to go out and view it,” NASA meteor expert Bill Cooke tells Space.com.

You’ll probably be able to see 60 to 70 meteors per hour at its peak. The most important consideration is to head somewhere with dark skies and little light pollution. For guidance, you can check out this online map of artificial sky brightness. Once you arrive at your preferred viewing spot, wait for the sky to get completely dark—about 2 to 3 hours after sunset.

Swift-Tuttle, the same comet that gives us these dazzling meteor displays, might also collide with Earth and wipe out life as we know it—but not for another 2460 years, at the very least. So until then, sit back and enjoy the cosmic show.

[h/t Forbes]

10 Facts About the Dwarf Planet Eris

An artist's rendering of the dwarf planet Eris
An artist's rendering of the dwarf planet Eris
ESO/L. Calçada and Nick Risinger (skysurvey.org) // CC BY 4.0

Far beyond the orbit of Pluto exists a celestial body that’s a little smaller, a little colder, and a little denser—the dwarf planet Eris. In Greek mythology, Eris is the goddess of strife, and never was there a more appropriately named body in the solar system. When astronomer Mike Brown of Caltech and his team discovered Eris in 2005, the finding set off a chain reaction that would see the planetary status of Pluto called into question. Here are 10 things you might not know about Eris.

1. An Eridian day is just slightly longer than Earth's.

If you were an astronaut, you wouldn’t find an Eridian day, at 25.9 hours, too disconcerting. This compares favorably with, say, Venus, whose day lasts 5832 hours (admittedly, it's an outlier). An Eridian year is a bit longer than what we're used to, with the dwarf planet completing an orbit of the Sun every 557 Earth years. And that orbit is not along the relatively flat plane with the orbits of most of the other planets of the solar system. Imagine your elementary school solar system model of planets on wires around a light bulb: Instead of a path neatly aligned with the other planets, Eris’s orbit is tilted at a 44 degree angle.

2. Eris was once thought to be bigger than Pluto.

After Eris’s discovery, the best measurements then available placed it as slightly larger than Pluto, with a radius of 722 miles. But after the initial spacecraft reconnaissance of Pluto by New Horizons in 2015, Pluto’s ranking as the ninth-largest planetary object orbiting the Sun was restored; it is now known to have a radius of 736 miles. In comparison, Earth’s Moon has a radius of 1079 miles. Ganymede, Callisto, Io, and Europa (Jupiter’s largest moons), Titan (Saturn’s largest moon), and Triton (Neptune’s largest moon) are also bigger than Pluto. On the other hand, Eris is 34 percent denser than Pluto.

3. Eris is responsible for the big debate over the definition of "planet."

When Brown’s team discovered Eris, it was initially hailed as either the 10th planet of the solar system, or a big problem for scientists who like nicely ordered celestial objects. The discovery of Eris came on the heels of the discoveries of Sedna and Quaoar, both beyond the orbit of Neptune. Astronomers were looking at the possibility of a dozen planets in the solar system or more, because—based on these three—who knew how many Pluto-sized bodies were out there? The International Astronomical Union eventually defined a planet in our solar system as something that has achieved hydrostatic equilibrium (in other words, it's round), orbits the Sun, and has “cleared its neighborhood” (i.e., is gravitationally dominant in its orbit). Yet the debate continues [PDF].

4. It has its own moon.

Eris has a moon called Dysnomia that circles the dwarf planet every 16 days. In Greek mythology, Dysnomia is the name of one of Eris’s daughters and means “anarchy.”

5. Initially, Eris was called Xena.

Before it was called Eris, it was called 2003 UB313 (a provisional designation by the International Astronomical Union). But before that, Brown’s team of astronomers named it Xena—yes, of Warrior Princess fame. “We always wanted to name something Xena,” Brown told The New York Times in 2005 after the discovery. Among Brown’s colleagues, Dysnomia was called Gabrielle, who was, of course, Xena’s sidekick.

6. Its surface is like Pluto's heart.

The primary way to analyze the composition of the surface of a celestial body is through spectroscopy, which is basically looking at an object and seeing how much light comes back at you as a function of wavelength. Many materials have characteristic absorptions of light at certain frequencies, and so less light will come back to you at that frequency.

“Eris has very, very strong methane ice absorption bands,” Will Grundy, a planetary scientist at Lowell Observatory and a member of the New Horizons team, tells Mental Floss. “They are much stronger than Pluto’s, and of course we’ve seen methane all over the place on Pluto, so I think it’ll be more ubiquitous on Eris’s surface.” The implication is that Eris is more than just a dead ice rock in space, because methane degrades very quickly in a space environment, darkening and forming heavier hydrocarbons. “The fact that it’s bright and covered with methane ice says it’s refreshing its surface relatively rapidly, and there are any number of ways it can do that. One is the methane just periodically sublimates underneath the atmosphere and then re-condenses somewhere else, just sort of painting on top of whatever dark stuff that forms,” Grundy says.

7. Pluto data enriches our understanding of Eris.

Pluto data returned from the New Horizons spacecraft give scientists new ideas about the processes that might be at work on Eris. “One of the things the Pluto flyby showed us that nobody really talked about, even in wild speculations, was something like Sputnik Planitia: this big, bright, teardrop-shaped region on the encounter hemisphere. Volatile ices there are trapped in a deep basin and they are just convectively overturning, like a simmering pot of soup,” Grundy says.

That process might be happening writ large on Eris. It might be, in a sense, an ice lava lamp planet. “I’ve called it a Sputnik planet,” Grundy says, “but nature is much more clever than scientists at coming up with new ways of doing things with the same old ingredients. Who knows, we might get there and find out it’s doing something completely different than Pluto was doing to refresh its surface. The real lesson is that activity on a lot of different timescales is possible, even on a tiny little planet that’s at frigid temperatures, far away from the sun.”

8. Its neighborhood is a potential gold mine of information.

In comparative planetology, scientists use planets to understand other planets. By studying Venus, which is similar to Earth in terms of size, mass, and basic composition, scientists can better understand how our planet operates and evolved. The objects in Eris’s celestial neighborhood work the same way. “The Kuiper Belt”—a region rich in rocky and icy objects beyond Neptune’s orbit—“is an incredibly rich environment for comparative planetology because there are so just many of these tiny planets out there,” Grundy says. “It’s going to take a while to discover them all, let alone explore them all, but that’s what is exciting about it.” The New Horizons data from Pluto are helping planetary scientists develop models to tease out the secrets of Eris.

9. Geologists could learn a lot, too.

“If you work out the surface area of, say, objects there that are bigger than 100 kilometers, based on extrapolation, the Kuiper Belt has more solid geology surface area than of all of the planets in the solar system—including the terrestrial planets—combined,” Grundy explains, adding that it holds true even if you wanted to include the ocean floor on Earth. “If you like geology—and especially if you like exotic, cryogenic temperature geology—this is the place to explore, and there’s just so much territory to explore out there.”

10. A mission to Eris will take a while.

It took New Horizons, one of the fastest spacecrafts ever built, nine years to get to Pluto. Eris is currently three times farther from the Sun than Pluto (though due to a highly elliptical orbit, this number changes), so if a mission is ever approved, don’t expect to find out how it all ends. “It takes decades to pull something like that together, so if you want to be around to see the results, you’ve got to start young,” Grundy says. A possible future Kuiper Belt mission might be part of a flyby mission to Uranus or Neptune, after which the spacecraft would continue into that region of space. It will be a very long time before technology allows an Earth-centric telescope—in space or otherwise—to take pictures of the geology of Eris.

The Geminid Meteor Shower Peaks This Week: Here's When and Where to See It

iStock.com/sripfoto
iStock.com/sripfoto

Star-gazers are in for a treat this week with the Geminid meteor shower set to light up skies across the globe. According to Space.com, the shower produces consistently stunning light shows this time each year, with meteors that are fast, frequent, and bright depending on where they're viewed. Whether you catch the spectacle every December or you'll be watching it for the first time, there's some important information to know before the 2018 event.

While most meteor showers are the product of our planet passing through the tail of a comet, the Geminid meteors come from something different: A small, rocky asteroid called 3200 Phaethon that leaves a wake of fiery debris like a comet. Its orbit brings it very close to the Sun, and when this happens, bits of rock break off in the heat and trail the object through space. (Some astronomers refer to 3200 Phaethon as a "rock comet.")

When the Earth passes through the tail, the debris burns up in the atmosphere, producing a bright show that's visible from the ground. And because the matter that trails 3200 Phaethon is denser than what you'd find behind a comet, it takes longer to burn up, creating a brighter spark and sometimes breaking up into multiple meteorites. This year viewers can expect to see more than one meteor a minute with up to 100 meteors per hour at the shower's peak.

The shower peaks the night of Thursday, December 13 and early Friday morning on December 14. The best time to watch is when the skies are darkest, usually around 2 a.m. local time. Unlike two years ago, when the Geminids coincided with a supermoon, the Moon will set around midnight on Thursday so viewing conditions will be ideal.

The Geminid meteor shower is visible around the world, though it's most prominent in the northern hemisphere. As is the case with all celestial events, people who live as far away from cities as possible will get the best view, but even people watching from the suburbs could catch as many as 30 meteors an hour.

[h/t Space.com]

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