If you’re planning some kind of outdoor nocturnal mischief this November, we recommend you avoid the 14th, when a gargantuan supermoon will light up the night sky. If you’re not, we recommend that you get outside and enjoy it.
Supermoons aren’t rare—we typically get between four and six each year—but this month’s is extra special for a few reasons. It’s a full moon, for one, and will be orbiting extraordinarily close to Earth. We haven’t been this close to our lunar satellite since January 1948, and we won’t be again until November 2034.
The Moon’s proximity to Earth and its position relative to the Sun will create a jaw-dropping spectacle, with the Moon appearing up to 14 percent bigger and 30 percent brighter than normal full moons.
If you’re the early-to-bed type or expect to be stuck inside that evening, don’t fret: the supermoon’s peak will actually occur during morning rush hour at 8:52 a.m. EST. Plus, we'll remind you the day before.
And while you’ve got your calendar out, take note: we’ll get another, albeit lesser, supermoon again on December 14.
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.
Neptune is like a celestial paint swatch: a stunning royal blue that demands attention. The eighth planet in the solar system, it is one half of the ice-giant system (the other half being Uranus), and among the most mysterious worlds circling our Sun. Mental Floss spoke to Mark Hofstadter, a planetary scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, to learn more about this lesser-known planet. Here are a few things you might not know.
1. IT HAS SIX RINGS AND 14 MOONS, ONE OF WHICH HAS GEYSERS BLASTING INTO SPACE.
Neptune is about 30 times farther than we are from the Sun (2.8 billion miles to our 93 million miles)—the farthest in the solar system (aside from the dwarf planets). Its effective temperature, according to NASA, is -353°F. Its mass is 17.1 times that of Earth, and it's big (but not Jupiter big), with an equatorial radius of 15,300 miles. Neptune is circled by six rings and has 14 moons, one of which is geologically active and blasting geysers into space. (Plumes are ideal for sampling; rather than building a lander, you can just fly a science spacecraft right through them.) A Neptunian day is short, at 16.11 hours long, but its years are a different story.
2. IN 2011, HUMANITY MARKED NEPTUNE'S "FIRST" BIRTHDAY.
It is impossible to see Neptune with the naked eye. Galileo first recorded its existence with his telescope, though he identified it as a star, misled by its slow orbit. In the 19th century, astronomers noticed an aberration in the orbit of Uranus, and Urbain Joseph Le Verrier, a French mathematician, went to work on the problem. With a pen and paper, he worked out not only the existence of a planet, but also its mass and position. In 1846, Johann Gottfried Galle made the observation at the request of Le Verrier, and sure enough, found a planet. A couple of weeks later, he also observed Triton, Neptune's largest moon.
It took 165 years for a full Neptunian year to elapse. That's why we celebrated Neptune's "first" birthday in 2011.
3. IT'S CALLED AN ICE GIANT … BUT IT DOESN'T HAVE MUCH ICE.
Hofstadter tells Mental Floss that until the Voyager 2 spacecraft visited Neptune and Uranus in the late 1980s, the two planets were thought to be small Jupiters. "It turns out they are fundamentally different than Jupiter," he says. "They are around two-thirds water by mass, and then they have some rock and an atmosphere of hydrogen and helium."
The "ice" in "ice giants" refers to their formation in the interstellar medium. "When modeling the formation of the solar system, things are more or less sorted into three categories: gas, rock, or ice," says Hofstadter. In interstellar space, helium or hydrogen will not exist as a solid or liquid, so they are the gases. They form planets like Jupiter. Silicates and irons, meanwhile, are solid, and exist as dust particles blown out from such things as supernovae. They form places like Earth. Then there are "in between" molecules, such as water, methane, or ammonia. Depending on the local temperatures and pressure, they might be water vapor or solid ice. Those are called—you guessed it—the ices.
"When planetary scientists found that, wow, Neptune and Uranus seem to be mostly stuff like water and methane, they called them 'ice giants,'" Hofstadter explains. But the name is misleading, because today there is very little ice in those planets. "When they formed, the water was probably coming in as ice," he says. "Now, however, it's hot enough in the interior that almost all of the water there is liquid."
Neptune's blue hue? That's due to the methane in its atmosphere.
4. IT HAS A SOLID CORE SURROUNDED BY AN OCEAN. THE REST IS A MYSTERY.
… but not liquid water like you find on Earth. The interior structures of Neptune and Uranus are among the biggest questions facing planetary scientists today. The conventional thinking is that there is a rocky core at each of their centers, surrounded by an extensive region of ocean. A hydrogen and helium atmosphere comprises the outer layer. "There's a lot of atmosphere to get through before you hit the ocean," says Hofstadter. "It is deep enough that it is under extremely high pressure and temperatures. It is probably a highly reactive ionic ocean." The water exists in what is called a supercritical state: "It doesn't behave in the same way that water in our oceans behave. It's probably conducting and has a lot of free electrons in it."
5. NEPTUNE'S FORMATION IS ONE OF THE GREAT CELESTIAL UNKNOWNS.
When planets form, solids first come together. When a solid ball gets big enough, it can gravitationally trap gas—and there's a lot more gas around than there is rock. Hydrogen is the most abundant thing in the universe. "Once you get a rocky core that's big enough to trap gas, a planet can grow very rapidly and can grow very big," says Hofstadter. In the inner solar system, where there was not as much gas, or ices were not solid, you got the terrestrial planets. In the outer solar system, where there was rock and solid ice, large cores formed quickly and started sucking up all the gas around them. That's how you get monster planets like Jupiter and Saturn.
How this relates to Neptune (and Uranus): A star, as it is forming, has a phase during which it has a tremendously strong stellar wind and effectively blows away all the gas. "If Jupiter and Saturn had been in an environment with an endless supply of gas, they would have grown big enough to eventually become stars," says Hofstadter. "But the idea is, the Sun kind of turned on and blew away all the gas, and Jupiter and Saturn had their growth cut off."
Neptune and Uranus have large cores big enough to trap gas. So the question is, why didn't they become like Jupiter and Saturn? "Jupiter and Saturn are 80 percent gas, by mass. Why are Uranus and Neptune something like 10 percent gas? Why didn't they trap more?"
The first theory involves luck. "The idea is, well, for Uranus and Neptune, their cores got big enough to trap gas precisely at the time when the Sun started blowing away all the gas. There wasn't enough, and they couldn't trap more," Hofstadter says. It's possible that could happen once or perhaps twice in a solar system's formation, explaining Uranus and Neptune. But the study of exoplanets have upended this thinking. "When you look around in our galaxy and see how many ice giants there are, it's hard to believe that every solar system out there was lucky enough to have planets forming large cores just as their stars started blowing away all the gas," he points out. "So this is a fundamental question: How do ice giants form? And we don't understand."
6. NEPTUNE'S RINGS ARE CLUMPY.
Unlike the rings of Saturn, the six Neptunian rings are thin, young, and dark. Their color is due to their composition: radiation-processed organic material. One of the rings features three thick, distinct clumps named Liberty, Equality, and Fraternity. The clumps are something of a mystery: The laws of physics dictate that they should be spread out evenly, as you see at Uranus, but there they are, little lumps in space. (Before Voyager 2 visited, only the clumps were visible, and were called arcs, part of an incomplete ring.) The most likely cause for the ring irregularity is gravitational meddling by the moon Galatea.
7. MORE ABOUT THAT MOON WITH GEYSERS …
Triton, Neptune's largest moon, is thought to be something like Pluto: an object from the Kuiper Belt (the ring of icy bodies beyond Neptune). "It happened to be gravitationally captured by Neptune," says Hofstadter. "It is a fascinating object to study because it's a Kuiper Belt object, but it's also interesting because it is active. We see a lot of geology on Triton just like we see on Pluto. When Voyager flew by—in just a few minutes—it happened to see geysers spouting off."
When Triton was captured into orbit around Neptune—you can see it circling the planet in the video above—it caused all the native Neptunian satellites to be destroyed. They either impacted Neptune and were absorbed, or they were ejected from the Neptunian system.
8. IT HAS A "GREAT DARK SPOT."
Just as Jupiter has a Great Red Spot, Neptune has a Great Dark Spot. They are both anticyclonic storms, though while Jupiter's spot is centuries old, Neptune's spot is short lived. It seems to come and go. Notably, the Great Dark Spot even generated stunning white clouds over Neptune much in the way that cirrus clouds form from cyclones on Earth.
9. WE'VE BEEN THERE ONCE BUT WANT TO GO BACK.
Only one spacecraft has visited Neptune: Voyager 2, in 1989. The photo of Neptune at top was taken during that mission; in fact, it's likely the source of any image of Neptune you've ever seen. Pretty much everything scientists know about the world comes from that flyby, and from telescopic observation. The James Webb Space Telescope [PDF], which launches in 2019, will unlock new ice-giant science, including mapping cloud structures, observing auroras, and studying post-impact atmospheric dynamics.
Some things, however, such as a detailed atmospheric composition or a study of its satellites, can only be done by a spacecraft at the system. Planetary scientists are today developing flagship-class missions to visit both Neptune and Uranus. An ice-giants mission is considered a top priority of the planetary science community, after a Mars sample return mission and a Europa orbiter. Mars 2020, which launches in its namesake year, is a sample-caching rover (returning those samples to Earth awaits a future mission); meanwhile, the Europa Clipper was approved by NASA and is well into development. That puts Neptune and Uranus next in line. A mission to these planets would have to launch no later than 2034 lest their orbits place them beyond easy reach.