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May 9, 2017
One of the most unusual features in the Saturnian atmosphere is the North Pole hexagonal cloud pattern. There’s a vortex at the heart of the pattern that looks exactly like the eyewall of a hurricane here on Earth.
The outer solar system, where temperatures were colder, was more hospitable to planetesimals (the seeds of planets) that were rich in volatiles (gassy materials) and ices.
Some of those ice crystals fall back to Enceladus as a fine snow. This venting process is called cryovolcanism,
became clear that Herschel’s “comet” was really a planet.
The five largest moons are Ariel, Umbriel,
Titania, Miranda, and Oberon. Each is a small, icy body with many cracks and craters on its surface.
Miranda is torn apart by the action of cryovolcanism—ice volcanoes spewing softened and slushy ice across the surface.
Look up video on cryovolcanism
This jagged scar on Miranda is named Verona Rupes, and it is the tallest known cliff in the solar system.
but scientists suspect that they may be ice particles coated with some kind of complex organic material. Oddly enough, the rings seem to be disappearing, and the reasons why are still being debated.
They’re locked together in what’s called a tidal resonance, which means that they each present the same face to each other as they orbit around their common center of gravity.
Most of the other worlds orbit near the plane of the solar system, but Pluto’s orbit takes it above and below the plane.
world. It was the first planet discovered in the new century, and it was found by an American. At the suggestion of an English schoolgirl named Venetia Burney, Tombaugh named his discovery Pluto and noted that the first two
letters were also a salute to Percival Lowell, who had died some years earlier. Later, it turned out that the extra perturbations in Uranus’s and Neptune’s orbits were the result of a mathematical error, and not due to Pluto’s influence.
As a comet gets close to the Sun, those ices begin to vaporize—the technical term is sublimation. This
Interestingly, comets are known to leave behind streams of particles, which are eventually spread out along the path of the comet’s orbit. When Earth encounters one of those streams, the material gets caught up in our atmosphere. As particles from the stream fall to the surface, they vaporize in the atmosphere, creating meteors.
Technically, what you saw was a piece of solar system debris vaporizing in Earth’s atmosphere and leaving behind a visible path called a meteor. If any piece of it survived the trip and fell to the ground, the remaining rocky bits would be called meteorites. Some
Think You Have a Meteorite? People often run across rocks they think are meteorites. A true meteorite will be very dense and feel quite heavy. It’s usually magnetic and may have small inclusions called chondrules embedded in it. Most meteorites have what’s called a fusion crust, which is a black, ash-like, darkened exterior. The surface also has smoothed depressions and cavities that look like thumbprints. These are called regmaglypts. Finally, most are made of a mixture of iron and nickel. If you find something you think might be a rock from space, take it to a local observatory or a college
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Meteor Showers
Meteorite Types
Asteroids are grouped into three main types:
Some asteroids come close to Earth but don’t always cross
our orbital path. They’re called Near-Earth Asteroids (NEAs for short). At least 10,000 of these close neighbors
Those that are the greatest threat are called Potentially Hazardous Asteroids (PHAs), and once they are discovered, they’re tracked very carefully.
The classes are O, B, A, F, G, K, and M, with O-type stars being the hottest, densest hypergiants and K and M stars being the coolest red dwarfs and supergiants. Some classifications contain even cooler-temperature objects that might be brown dwarfs (objects too hot to be planets and too cool to be stars) or even rogue planets. They are labeled L, T, and Y, and some of them are known to be cooler than planets.
fusing hydrogen
The bigger the magnitude number, the dimmer the object. The smaller the number (and this includes negative numbers), the brighter the celestial object.
dark nebula, a cloud that is so dense that light can’t pass through it.
helium. That process releases energy in the form of heat and light, and that’s what powers stars. The birth of the star is marked by the moment when nuclear fusion begins.
Wherever temperatures and pressures are high enough,
a star will form.
emission nebula
Eta Carinae
Nicknamed “the Homunculus,” it lies about 7,500 light-years away in the Southern Hemisphere constellation of Carina.
“the Tarantula Nebula.”
stellar nucleosynthesis.
stellar winds
supernova explosions.
white dwarfs
black dwarfs.
It’s on the main sequence, a phase where stars spend their time fusing hydrogen in their cores. When they stop fusing hydrogen, they leave the main sequence, and that’s when things get interesting. The aging and death process of a star depends very much on its starting mass. A star like the Sun dies very differently than a star that is forty times more massive.
asymptotic giant branch star.
mass loss.
planetary nebula.
neutron star.
the original star is very massive (say greater than twenty-five solar masses), the core can keep condensing to become a stellar black hole.
pulsar (from the two words pulsating star)
Black holes are massive, dense objects with gravity so strong that nothing—not even light—can get out. That makes black holes themselves impossible to see. However, their effects can be detected.
There are three kinds of black holes: Mini black holes, which were created in the first moments of the universe and have probably all evaporated Stellar black holes, which form during the deaths of very massive stars Supermassive black holes, which live in the hearts of galaxies
black holes also have an electric charge,
most have angular momentum, or spin, which comes from the original rotation of the star that collapsed.
