10 Discoveries That Shed Light On Mysteries Of Our Solar System

Sometimes, we get so caught up in trying to find aliens on exoplanets that we forget how many mysteries our own solar system contains. Fortunately, our scientists keep searching for clues to solve the puzzles in our little corner of the universe.

The Puzzling Temperature Of The Sun’s Corona


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As we’ve discussed before, scientists have wondered for decades why the temperature of the Sun’s corona, or outer atmosphere, is so much hotter than its photosphere, or visible surface. Defying all logic, the surface of the Sun has a temperature around 6,000 Kelvin (about 6,000 degrees Celsius, or 10,000 °F), while the corona often becomes 300 times hotter. “That’s a bit of a puzzle,” said Jeff Brosius, a space scientist at NASA’s Goddard Space Flight Center in Maryland. “Things usually get cooler farther away from a hot source. When you’re roasting a marshmallow you move it closer to the fire to cook it, not farther away.”

But scientists recently found strong evidence that nanoflares, and the energetic particles produced by them, are at least part of the source of the extra heat. Although nanoflares are the tiny cousins of solar flares (which may heat solar plasma to tens of millions of degrees in only seconds), they still produce small, quick bursts of heat and energy almost constantly. We can’t see them directly yet, but that problem may be solved when NASA’s NuSTAR space telescope takes high-energy X-ray portraits of them. But scientists can’t take those pictures until the Sun is quieter; otherwise, all the energetic activity may hide the action of the nanoflares.

Until then, the Interface Region Imaging Spectrograph (IRIS) gives us the best way to detect nanoflares indirectly by looking at coronal loop footpoints. A coronal loop is a hot plasma loop reaching out from the surface of the Sun into the corona that glows brightly in ultraviolet and X-rays. A footpointoccurs where magnetic loops meet the Sun’s surface. IRIS can’t see the actual coronal heating events, but it does see the telltale rapid, small brightenings at the coronal loop footpoints.

While other theories have been disproven, increasing evidence points to nanoflares as the solution to the coronal heating mystery. If it’s correct, NuSTAR should see at least one nanoflare every few minutes. If it doesn’t, it’s time to go back to the drawing board.

The Origin Of Dark Material On Protoplanet Vesta


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Rocks can tell us a lot about a protoplanet’s evolution because they can only be formed under specific conditions. NASA’s spacecraft Dawn recently gave us information on the puzzling dark matter that’s spread all over Vesta’s surface. It absorbs light like soot. But our scientists were curious to know what it was made of and where it came from. That might give them some insight into why Vesta started to become a planet over four billion years ago but never made the evolutionary leap beyond protoplanet.

For more than a year, scientists have known that the dark material was high in carbon. But recently, they discovered that serpentine, a rock-forming silicate mineral, was an element of the dark matter. Serpentine is named for its resemblance to snakeskin.

That one mineral solves some of the mystery of Vesta’s formation. The dark matter can’t have come in contact with high levels of heat because temperatures above 400 degrees Celsius (700 °F) would destroy serpentine. We already know that Vesta was quite hot at one time, so the dark matter couldn’t have come from Vesta itself.

That leaves a relatively slow impact from a carbon-rich asteroid as the only logical explanation. If the impact had been high-speed, then the serpentine would have been destroyed by the resulting high temperature. The dispersion of dark material on Vesta is also consistent with a low-speed impact from an asteroid.

The Mystery Of Venus’s Atmosphere


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“This work all started with a mystery from 1978,” said Glyn Collinson from NASA’s Goddard Space Flight Center in Maryland. “When Pioneer Venus Orbiter moved into orbit around Venus, it noticed something very, very weird—a hole in the planet’s ionosphere. It was a region where the density just dropped out, and no one has seen another one of these things for 30 years.”

The ionosphere is a layer of atmosphere on Venus that’s electrically charged. When the European Space Agency’s Venus Express began to orbit Venus in recent years, it was in a much higher orbit than that of its predecessor. But even at the higher altitude, Venus Express saw the same holes. That meant these holes had drilled farther down into the atmosphere than once believed. In addition, Pioneer Venus Orbiter observed the holes at the solar maximum, when solar activity is at its peak. But Venus Express saw holes during the solar minimum which means these holes are more prevalent than we realized.

To interpret what’s happening to Venus, it’s necessary to understand that the side of its ionosphere facing the Sun is hammered constantly by solar wind, a stream of charged particles flowing from the Sun. The ionosphere acts like a thin boundary that extends from the front of Venus around the planet until tailing off in the back like a comet. Think of the ionosphere as the air streaming around a golf ball that’s in flight. space space science earth science space station science space travel space science earth science space station science

When the solar wind hits the ionosphere, the plasma piles up, which in turn creates a thin magnetosphere around the planet. A magnetosphere is an area around a planet where its magnetic field may repel solar wind.

Venus Express can measure this weak magnetic field around Venus. But it suggested that there weren’t two holes behind Venus. Instead, scientists now believe that there are two wide, long cylinders that extend from the surface of Venus into outer space. It’s possible that charged particles are squeezed out of these cylinders like toothpaste from a tube.

But that raises another compelling mystery. What allows these magnetic fields to cut through the ionosphere, go down to the planet surface, and possibly even enter the planet? We may have shed light on one Venus mystery, but we ended up with another one.

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