S.p.a.c.e.

Uranus taken by Voyager 2 on January 11 1986. 

Credit: NASA/JPL-Caltech/Kevin M. Gill

Tulip Nebula in Cygnus

50 Facts About Earth

3D Bennu : Put on your red/blue glasses and float next to asteroid 101955 Bennu. Shaped like a spinning toy top with boulders littering its rough surface, the tiny Solar System world is about one Empire State Building (less than 500 meters) across. Frames used to construct this 3D anaglyph were taken by PolyCam on the OSIRIS_REx spacecraft on December 3, 2018 from a distance of about 80 kilometers. With a sample from the asteroid’s rocky surface on board, OSIRIS_REx departed Bennu’s vicinity this May and is now enroute to planet Earth. The robotic spacecraft is scheduled to return the sample to Earth in September 2023. via NASA

New Science from our Mission to Touch the Sun

In August 2018, our Parker Solar Probe mission launched to space, soon becoming the closest-ever spacecraft from the Sun. Now, scientists have announced their first discoveries from this exploration of our star!

The Sun may look calm to us here on Earth, but it’s an active star, unleashing powerful bursts of light, deluges of particles moving near the speed of light and billion-ton clouds of magnetized material. All of this activity can affect our technology here on Earth and in space.

Parker Solar Probe’s main science goals are to understand the physics that drive this activity — and its up-close look has given us a brand-new perspective. Here are a few highlights from what we’ve learned so far.

1. Surprising events in the solar wind

The Sun releases a continual outflow of magnetized material called the solar wind, which shapes space weather near Earth. Observed near Earth, the solar wind is a relatively uniform flow of plasma, with occasional turbulent tumbles. Closer to the solar wind’s source, Parker Solar Probe saw a much different picture: a complicated, active system. 

One type of event in particular drew the eye of the science teams: flips in the direction of the magnetic field, which flows out from the Sun, embedded in the solar wind. These reversals — dubbed “switchbacks” — last anywhere from a few seconds to several minutes as they flow over Parker Solar Probe. During a switchback, the magnetic field whips back on itself until it is pointed almost directly back at the Sun.

The exact source of the switchbacks isn’t yet understood, but Parker Solar Probe’s measurements have allowed scientists to narrow down the possibilities — and observations from the mission’s 21 remaining solar flybys should help scientists better understand these events. 

2. Seeing tiny particle events

The Sun can accelerate tiny electrons and ions into storms of energetic particles that rocket through the solar system at nearly the speed of light. These particles carry a lot of energy, so they can damage spacecraft electronics and even endanger astronauts, especially those in deep space, outside the protection of Earth’s magnetic field — and the short warning time for such particles makes them difficult to avoid.

Energetic particles from the Sun impact a detector on ESA & NASA’s SOHO satellite.

Parker Solar Probe’s energetic particle instruments have measured several never-before-seen events so small that all trace of them is lost before they reach Earth. These instruments have also measured a rare type of particle burst with a particularly high number of heavier elements — suggesting that both types of events may be more common than scientists previously thought.

3. Rotation of the solar wind

Near Earth, we see the solar wind flowing almost straight out from the Sun in all directions. But the Sun rotates as it releases the solar wind, and before it breaks free, the wind spins along in sync with the Sun’s surface. For the first time, Parker was able to observe the solar wind while it was still rotating – starting more than 20 million miles from the Sun.

The strength of the circulation was stronger than many scientists had predicted, but it also transitioned more quickly than predicted to an outward flow, which helps mask the effects of that fast rotation from the vantage point where we usually see them from, near Earth, about 93 million miles away. Understanding this transition point in the solar wind is key to helping us understand how the Sun sheds energy, with implications for the lifecycles of stars and the formation of protoplanetary disks.

4. Hints of a dust-free zone

Parker also saw the first direct evidence of dust starting to thin out near the Sun – an effect that has been theorized for nearly a century, but has been impossible to measure until now. Space is awash in dust, the cosmic crumbs of collisions that formed planets, asteroids, comets and other celestial bodies billions of years ago. Scientists have long suspected that, close to the Sun, this dust would be heated to high temperatures by powerful sunlight, turning it into a gas and creating a dust-free region around the Sun.

For the first time, Parker’s imagers saw the cosmic dust begin to thin out a little over 7 million miles from the Sun. This decrease in dust continues steadily to the current limits of Parker Solar Probe’s instruments, measurements at a little over 4 million miles from the Sun. At that rate of thinning, scientists expect to see a truly dust-free zone starting a little more than 2-3 million miles from the Sun — meaning the spacecraft could observe the dust-free zone as early as 2020, when its sixth flyby of the Sun will carry it closer to our star than ever before.

These are just a few of Parker Solar Probe’s first discoveries, and there’s plenty more science to come throughout the mission! For the latest on our Sun, follow @NASASun on Twitter and NASA Sun Science on Facebook.

Snaking Filament Eruption by NASA Goddard Photo and Video

The glow of ionized hydrogen in the Flame Nebula, in Orions belt, by Adam Block

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Happy 4th of July… From Space!

In Hollywood blockbusters, explosions and eruptions are often among the stars of the show. In space, explosions, eruptions and twinkling of actual stars are a focus for scientists who hope to better understand their births, lives, deaths and how they interact with their surroundings. Spend some of your Fourth of July taking a look at these celestial phenomenon:

Credit: NASA/Chandra X-ray Observatory

An Astral Exhibition

This object became a sensation in the astronomical community when a team of researchers pointed at it with our Chandra X-ray Observatory telescope in 1901, noting that it suddenly appeared as one of the brightest stars in the sky for a few days, before gradually fading away in brightness. Today, astronomers cite it as an example of a “classical nova,” an outburst produced by a thermonuclear explosion on the surface of a white dwarf star, the dense remnant of a Sun-like star.

Credit: NASA/Hubble Space Telescope

A Twinkling Tapestry

The brilliant tapestry of young stars flaring to life resemble a glittering fireworks display. The sparkling centerpiece is a giant cluster of about 3,000 stars called Westerlund 2, named for Swedish astronomer Bengt Westerlund who discovered the grouping in the 1960s. The cluster resides in a raucous stellar breeding ground located 20,000 light-years away from Earth in the constellation Carina.

Credit: NASA/THEMIS/Sebastian Saarloos

An Illuminating Aurora

Sometimes during solar magnetic events, solar explosions hurl clouds of magnetized particles into space. Traveling more than a million miles per hour, these coronal mass ejections, or CMEs, made up of hot material called plasma take up to three days to reach Earth. Spacecraft and satellites in the path of CMEs can experience glitches as these plasma clouds pass by. In near-Earth space, magnetic reconnection incites explosions of energy driving charged solar particles to collide with atoms in Earth’s upper atmosphere. We see these collisions near Earth’s polar regions as the aurora. Three spacecraft from our Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission, observed these outbursts known as substorms.

Credit: NASA/Hubble Space Telescope//ESA/STScI

A Shining Supermassive Merger

Every galaxy has a black hole at its center. Usually they are quiet, without gas accretions, like the one in our Milky Way. But if a star creeps too close to the black hole, the gravitational tides can rip away the star’s gaseous matter. Like water spinning around a drain, the gas swirls into a disk around the black hole at such speeds that it heats to millions of degrees. As an inner ring of gas spins into the black hole, gas particles shoot outward from the black hole’s polar regions. Like bullets shot from a rifle, they zoom through the jets at velocities close to the speed of light. Astronomers using our Hubble Space Telescope observed correlations between supermassive black holes and an event similar to tidal disruption, pictured above in the Centaurus A galaxy. 

Credit: NASA/Hubble Space Telescope/ESA

A Stellar Explosion

Supernovae can occur one of two ways. The first occurs when a white dwarf—the remains of a dead star—passes so close to a living star that its matter leaks into the white dwarf. This causes a catastrophic explosion. However most people understand supernovae as the death of a massive star. When the star runs out of fuel toward the end of its life, the gravity at its heart sucks the surrounding mass into its center. At the turn of the 19th century, the binary star system Eta Carinae was faint and undistinguished. Our Hubble Telescope captured this image of Eta Carinae, binary star system. The larger of the two stars in the Eta Carinae system is a huge and unstable star that is nearing the end of its life, and the event that the 19th century astronomers observed was a stellar near-death experience. Scientists call these outbursts supernova impostor events, because they appear similar to supernovae but stop just short of destroying their star.

Credit: NASA/GSFC/SDO

An Eye-Catching Eruption

Extremely energetic objects permeate the universe. But close to home, the Sun produces its own dazzling lightshow, producing the largest explosions in our solar system and driving powerful solar storms.. When solar activity contorts and realigns the Sun’s magnetic fields, vast amounts of energy can be driven into space. This phenomenon can create a sudden flash of light—a solar flare.The above picture features a filament eruption on the Sun, accompanied by solar flares captured by our Solar Dynamics Observatory.

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