Space
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Ever wondered what auroras look like from space?
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Sun's Magnetic Field Portrayed
NASA's Solar Dynamics Observatory (SDO) scientists used their computer models to generate a view of the Sun's magnetic field on August 10, 2018. The bright active region right at the central area of the Sun clearly shows a concentration of field lines, as well as the small active region at the Sun's right edge.1 -
Pluto was reclassified from a planet to a dwarf planet in 2006.
• Pluto was discovered on February 18th, 1930 by the Lowell Observatory.
• For the 76 years between Pluto being discovered and the time it was reclassified as a dwarf planet it completed under a third of its orbit around the Sun.
• Pluto has five known moons.
• Pluto is the largest dwarf planet.
• Pluto is one third water.
• This is in the form of water ice which is more than 3 times as much water as in all the Earth’s oceans, the remaining two thirds are rock. Pluto’s surface is covered with ices, and has several mountain ranges, light and dark regions, and a scattering of craters.
Pluto has a eccentric and inclined orbit.
This takes it between 4.4 and 7.3 billion km from the Sun meaning Pluto is periodically closer to the Sun than Neptune.4 -
The Hubble Ultra Deep Field from 2004 represents the deepest portrait of the visible universe ever achieved by humankind. Using the improved capabilities of the Advanced Camera for Surveys, the camera installed during the 2002 servicing mission, a new Deep Field was observed, in the constellation of Fornax (the Furnace).
It reveals some of the first galaxies to emerge from the "dark ages", the time shortly after the Big Bang when the first stars reheated the cold, dim universe.
The Ultra Deep Fields show the furthest away galaxies that can be observed in visible light.
Because the Universe expands, light waves from very distant objects is stretched during its long journey to us. The further away objects are from us, the more their light is stretched. As longer wavelengths appear redder than shorter wavelengths, this phenomenon is known as “redshift”, and it is somewhat similar to the Doppler effect heard when an ambulance siren drops in pitch as the vehicle speeds away.
For very distant objects, their light is shifted so far that they drop out of the visible spectrum altogether, and can only be seen in infrared light. This means that the Hubble Ultra Deep Field cannot be improved on by building a more sensitive optical telescope — Hubble has reached the limit of what is possible in visible light.
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Uranus is the seventh planet from the sun and the first to be discovered by scientists.
Although Uranus is visible to the naked eye, it was long mistaken as a star because of the planet's dimness and slow orbit.
The planet is also notable for its dramatic tilt, which causes its axis to point nearly directly at the sun.
Uranus is blue-green in color, the result of methane in its mostly hydrogen-helium atmosphere.
The planet is often dubbed an ice giant, since 80 percent or more of its mass is made up of a fluid mix of water, methane, and ammonia ices.
Unlike the other planets of the solar system, Uranus is tilted so far that it essentially orbits the sun on its side, with the axis of its spin nearly pointing at the star.
This unusual orientation might be due to a collision with a planet-size body, or several small bodies, soon after it was formed.
This unusual tilt gives rise to extreme seasons roughly 20 years long, meaning that for nearly a quarter of the Uranian year, equal to 84 Earth-years, the sun shines directly over each pole, leaving the other half of the planet to experience a long, dark, cold winter.1 -
Why is the Sun so quiet? As the Sun enters into a period of time known as a Solar Minimum, it is, as expected, showing fewer sunspots and active regions than usual. The quietness is somewhat unsettling, though, as so far this year, most days show no sunspots at all.
In contrast, from 2011 - 2015, during Solar Maximum, the Sun displayed spots just about every day. Maxima and minima occur on an 11-year cycle, with the last Solar Minimum being the most quiet in a century. Will this current Solar Minimum go even deeper? Even though the Sun's activity affects the Earth and its surroundings, no one knows for sure what the Sun will do next, and the physics behind the processes remain an active topic of research. The featured image was taken three weeks ago and shows that our Sun is busy even on a quiet day.
Prominences of hot plasma, some larger than the Earth, dance continually and are most easily visible over the edge.1 -
Gravitational Time Dilation.
This effect measures the amount of time that has elapsed between two events by observers at different distances from a gravitational mass. In other words, time runs slower wherever gravity is strongest, and this is because gravity curves space-time.
Think of it this way — time follows a simple equation:
speed = distance / time
Light (in this case, speed) is always constant and travels at a speed of 180,000 miles per second. Imagine two beams of light: one in a weak gravitational field traveling between points a and b, and the other in a strong gravitational field traveling between points c and d.
The path between c and d is longer due to the curving of space and time so it takes longer for light to travel between the two points. This effect has been proven by several experiments and is used to run and maintain something most of us use almost every single day: GPS.
Global Positioning System (GPS) satellites are positioned about 12,550 miles above Earth’s surface and therefore are not as close to Earth’s gravitational field. The clocks on these satellites tick faster than the clocks on Earth’s surface so scientists have put a correction into the satellite programs to ensure that the GPS data sent back to Earth’s surface have matching times. Without this correction, GPS satellites would not be the useful tool that we know them to be.1 -
Our sun's sphere of influence, composed of solar plasma and solar magnetic fields, is called the heliosphere. This gigantic structure is about three times wider than the orbit of Pluto. At the edge of the heliosphere lies the heliosheath, a boundary region between the solar system and interstellar space.
For decades, scientists had thought that, in the heliosheath, the sun's magnetic field curves around in a smooth, consistent arc, forming a relatively uniform structure.
But that appears not to be the case.
The twin unmanned probes Voyager 1 and Voyager 2, both launched in 1977, are currently plying different parts of the heliosheath, more than 9 billion miles (14.5 billion kilometers) from Earth. And their observations are spurring a rethink of the region.
Specifically, the probes measured abrupt changes in the flow of particles, such as electrons, from one patch of space to another.
"What really struck us were the sudden differences between what Voyager 1 was seeing and what Voyager 2 was seeing," said study co-author James Drake of the University of Maryland. "We had to explain, well, why is that?"
The best explanation, according to subsequent computer models, is that the probes are flying through a frothy field of magnetic bubbles. These bubbles act as particle traps. So particle readings increase while the spacecraft are inside one, then drop when they exit.
These bubbles form as a result of the interaction between the sun's rotation and its magnetic field. As the sun spins, its magnetic field churns and twists out in the heliosheath. The folded field bunches up on itself, causing lines of magnetic force to crisscross and reconnect, forming the sea of bubbles.
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Sounds like NASA is going to let SpaceX fuel their rockets with live astronauts inside of them! Wild.0
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Triton was discovered on Oct. 10, 1846 by British astronomer William Lassell, just 17 days after Neptune itself was discovered.
Triton is the largest of Neptune's 13 moons. It is unusual because it is the only large moon in our solar system that orbits in the opposite direction of its planet's rotation―a retrograde orbit.
Scientists think Triton is a Kuiper Belt Object captured by Neptune's gravity millions of years ago. It shares many similarities with Pluto, the best known world of the Kuiper Belt.
Like our own moon, Triton is locked in synchronous rotation with Neptune―one side faces the planet at all times. But because of its unusual orbital inclination both polar regions take turns facing the Sun.
Triton is one of the coolest objects in our solar system. It is so cold that most of Triton's nitrogen is condensed as frost, giving its surface an icy sheen that reflects 70 percent of the sunlight that hits it.
NASA's Voyager 2―the only spacecraft to fly past Neptune and Triton―found surface temperatures of -391degrees Fahrenheit (-235 degrees Celsius). During its 1989 flyby, Voyager 2 also found Triton has active geysers, making it one of the few geologically active moons in our solar system.1 -
I'm excited about the Webb telescope and what it will bring to us in the future3
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Glowing Elements in the Soul Nebula
Stars are forming in the Soul of the Queen of Aethopia. More specifically, a large star forming region called the Soul Nebula (IC 1898) can be found in the direction of the constellation Cassiopeia, who Greek mythology credits as the vain wife of a King who long ago ruled lands surrounding the upper Nile river.
The Soul Nebula houses several open clusters of stars, a large radio source known as W5, and huge evacuated bubbles formed by the winds of young massive stars. Located about 6,500 light years away, the Soul Nebula spans about 100 light years and is usually imaged next to its celestial neighbor the Heart Nebula (IC 1805).
The featured image is a composite of three exposures in different colors: red as emitted by hydrogen gas, yellow as emitted by sulfur, and blue as emitted by oxygen.2 -
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Asteroid Ryugu from Hayabusa2
This big space diamond has an estimated value of over 80 billion dollars. It's only diamond in shape, though -- asteroid 162173 Ryugu is thought to be composed of mostly nickel and iron. Asteroids like Ryugu are interesting for several reasons, perhaps foremost because they are near the Earth and might, one day in the far future, pose an impact threat. In the nearer term, Ryugu is interesting because it may be possible to send future spacecraft there to mine it, thus providing humanity with a new source of valuable metals.
Scientifically, Ryugu is interesting because it carries information about how our Solar System formed billions of years ago, and why its orbit takes it so close to Earth. Japan's robotic spacecraft Hayabusa2 just arrived at this one-kilometer wide asteroid in late June. The featured image shows surface structures unknown before spacecraft Hayabusa2's arrival, including rock fields and craters.
Within the next three months, Hayabusa2 is scheduled to unleash several probes, some that will land on Ryugu and hop around, while Hayabusa2 itself will mine just a little bit of the asteroid for return to Earth.1 -
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If two pieces of the same type of metal touch in space, they will bond and be permanently stuck together.
This amazing effect is called cold welding. It happens because the atoms of the individual pieces of metal have no way of knowing that they are different pieces of metal, so the lumps join together. This wouldn't happen on earth because there is air and water separating the pieces. The effect has a lot of implication for spacecraft construction and the future of metal-based construction in vacuums.1 -
Space Station Flight Over Hurricane Lane
NASA astronaut Ricky Arnold photographed a massive storm in the Pacific Ocean during a flyover from the International Space Station. Arnold shared images on social media on Aug. 22, 2018, and wrote, "#HurricaneLane in the early morning hours near #Hawaii. The crew of the @Space_Station sends much aloha to everyone there."1 -
The greenish coma of comet 21P/Giacobini-Zinner stands out at the left of this telephoto skyscape spanning over 10 degrees toward the northern constellations Cassiopeia and Perseus. Captured on August 17, the periodic comet is the known parent body of the upcoming Draconid meteor shower.
Predicted to be at its brightest next month, the comet is actually in the foreground of the rich starfield, only about 4 light-minutes from our fair planet. Giacobini-Zinner should remain too faint for your eye to see though, like the colorful Heart and Soul nebulae near the center of the sensitive digital camera's field of view. But the pair of open star clusters at the right, h and Chi Persei, could just be seen by the unaided eye from dark locations. The Heart and Soul nebulae with their own embedded clusters of young stars a million or so years old, are each over 200 light-years across and 6 to 7 thousand light-years away.
They are part of a large, active star forming complex sprawling along the Perseus spiral arm of our Milky Way Galaxy. Also known as the Double Cluster, h and Chi Persei are located at about that same distance. Periodic Giacobini-Zinner was visited by a spacecraft from Earth when the repurposed International Cometary Explorer passed through its tail in September 1985.1 -
The object on the right is a star that is 500 light years away - the one on the left is a Quasar that is 5 billion light years away!1 -
honeybee__12 wrote: »
The Latest: Three of the world's largest radio telescopes team up to show a rare double asteroid. 2017 YE5 is only the fourth binary near-Earth asteroid ever observed in which the two bodies are roughly the same size, and not touching.
This is better than a double rainbow..2 -
Reddened by scattered sunlight, the Moon in the center is passing through the center of Earth's dark umbral shadow in this July 27 lunar eclipse sequence. Left to right the three images are from the start, maximum, and end to 103 minutes of totality from the longest lunar eclipse of the 21st century. The longest path the Moon can follow through Earth's shadow does cross the shadow's center, that's what makes such central lunar eclipses long ones.
But July 27 was also the date of lunar apogee, and at the most distant part of its elliptical orbit the Moon moves slowest. For the previous lunar eclipse, last January 31, the Moon was near its orbital perigee. Passing just south of the Earth shadow central axis, totality lasted only 76 minutes. Coming up on January 21, 2019, a third consecutive total lunar eclipse will also be off center and find the Moon near perigee. Then totality will be a mere 62 minutes long.
Everlasting Gobstoppers.
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Messier 20 and 21
The beautiful Trifid Nebula, also known as Messier 20, is easy to find with a small telescope in the nebula rich constellation Sagittarius. About 5,000 light-years away, the colorful study in cosmic contrasts shares this well-composed, nearly 1 degree wide field with open star cluster Messier 21 (bottom right). Trisected by dust lanes the Trifid itself is about 40 light-years across and a mere 300,000 years old.
That makes it one of the youngest star forming regions in our sky, with newborn and embryonic stars embedded in its natal dust and gas clouds. Estimates of the distance to open star cluster M21 are similar to M20's, but though they share this gorgeous telescopic skyscape there is no apparent connection between the two. In fact, M21's stars are much older, about 8 million years old.2 -
This artist's concept illustrates the hottest planet yet observed in the universe. The scorching ball of gas, a "hot Jupiter" called HD 149026b, is a sweltering 3,700 degrees Fahrenheit (2,040 degrees Celsius) -- about 3 times hotter than the rocky surface of Venus, the hottest planet in our solar system. The planet is so hot that astronomers believe it is absorbing almost all of the heat from its star, and reflecting very little to no light. Objects that reflect no sunlight are black. Consequently, HD 149026b might be the blackest known planet in the universe, in addition to the hottest.
The temperature of this dark and balmy planet was taken with NASA's Spitzer Space Telescope. While the planet reflects no visible light, its heat causes it to radiate a little visible and a lot of infrared light. Spitzer, an infrared observatory, was able to measure this infrared light through a technique called secondary eclipse.
HD 149026b is what is known as a transiting planet, which means that it crosses in front of and passes behind its star -- the secondary eclipse -- when viewed from Earth. By determining the drop in total infrared light that occurs when the planet disappears, astronomers can figure out how much infrared light is coming from the planet alone.2 -
Planetary nebula NGC 3918
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Time-lapse Sequence of Jupiter’s North
Striking atmospheric features in Jupiter’s northern hemisphere are captured in this series of color-enhanced images from NASA’s Juno spacecraft.2 -
Awesome!0
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A bit of an aside, but I've been trying to get a good look at Mars in the telescope lately, and it is simultaneously cool and disappointing.
It's cool because it's close to Earth right now so you can get a pretty good view, but disappointing because all you see is a featureless, orange-red ball. Normally you can see at least the white poles, and make out lighter and darker features on the surface (at least in my 'scope). But the reason you can't see anything is because of a global sandstorm, and that's pretty cool. I understand the storm is starting to subside, though.2 -
A recent study out from Leiden Observatory and Cornell University may shed light on the curious case of one of the solar system's more exotic objects: 90377 Sedna.
A team led by astronomer Mike Brown discovered 90377 Sedna in late 2003. Provisionally named 2003 VB12, the object later received the name Sedna from the International Astronomical Union, after the Inuit goddess of the sea.
From the start, Sedna was an odd-ball. Its 11,400 year orbit takes it from a perihelion of 76 astronomical units (for context, Neptune is an average of 30 AUs from the sun) to an amazing 936 AUs from the sun. (A thousand AUs is 1.6% of a light year, and 0.4% of the way to Proxima Centauri, the closest star to our solar system). Currently at a distance of 86 AU and headed towards perihelion in 2076, we're lucky we caught Sedna as it 'neared' (we use the term 'near' loosely in this case!) the sun.
But this strange path makes you wonder what else is out there, and how Sedna wound up in such an eccentric orbit.
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