Happy 4th of Julyโฆ 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:ย NASA/Chandra X-ray Observatory
An Astral Exhibition
This object became a sensation in the astronomical community when a team of researchers pointed at itย with ourย Chandra X-ray Observatory telescopeย 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 โclassical nova,โ 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.ย 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 Earthโs upper atmosphere. We see these collisions near Earthโs polar regions as the aurora. Three spacecraft from ourย 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 starโs 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 holeโs 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.ย
Credit: NASA/Hubble Space Telescope/ESA
A Stellar Explosion
Supernovae can occur one of two ways. The first occurs when a white dwarfโthe remains of a dead starโpasses 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.ย 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 Sunโs magnetic fields, vast amounts of energy can be driven into space. This phenomenon can create a sudden flash of lightโa 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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