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  1. #1
    'ello 'ello 'ello Luigi's Avatar
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    Moons of the Solar System.

    Will start off with Phobos, the larger of the 2 Martian moons.



    The Deathstar.


    Phobos (pronounced FOH bus) is the largest of the two moons which orbit the planet Mars. It is also closer to it’s primary than any other satellite in the solar system. Phobos travels only 3,700 miles (6,000 km) above the surface of the red planet – by comparison the Moon is 384,400 km above Earth. Phobos orbits Mars three times per day.



    THE MOON IS NAMED FOR THE SON OF GREEK GOD OF WAR, ARES, AND MEANS FEAR

    In Greek mythology, Phobos is the son of Ares, the god of war and he is the personification of fear. He was known to join his father in battle along with his twin brother Deimos – the name of Mars’ other moon.
    PHOBOS MOVES ACROSS THE SKY OF MARS TWICE A DAY.

    It takes Phobos 4 hours and 15 minutes to move across the sky of Mars because of how close it is to the planet. The moon rises in the west, moves rapidly across the sky, and sets in the east twice every Martian day (every 11 h 6 min). This is because it orbits Mars below the synchronous orbit radius – this means it moves around Mars faster than Mars moves itself.
    PHOBOS IS MOST LIKELY AN ASTEROID

    Phobos is made up of the same matter as asteroids and dwarf planets, composed mostly of material similar to Type I or II carbonaceous chondrites. It’s density is too light to be solid rock and it is one of the least reflective objects in the solar system.






    IN 50 MILLION YEARS PHOBOS WILL COLLIDE WITH MARS.

    Due to tidal deceleration caused by Phobos orbiting Mars below the synchronous orbit radius, tidal bulges are decelerating Phobos’ orbit and it will gradually spiral closer to Mars. In 30-50 million years, Phobos will be destroyed – either by colliding with Mars or torn into rubble and scattered as a ring around Mars. The moon is spiralling inward at about 1.8 centimeters per year, or 1.8 meters (6 feet) each century.
    PHOBOS HAS AN IMPACT CRATER WHICH IS 9 KM (5.4 MI) WIDE.

    The largest crater on Phobos is 9 km wide and covered a large portion of the moon’s surface. The crater is called Stickney and named after Chloe Angeline Stickney Hall, the wife of Asaph Hall and discoverer of Phobos, in 1973. It is believed that the impact that created Stickney must have nearly shattered Phobos.
    THE TEMPERATURE ON PHOBOS RANGES FROM −4C TO −112C

    Temperatures on Phobos are around −4C (25F) on the sunlit side of the moon, down to around −112C (−170F) on the shadowed side.

    SOME PROMINENT SCIENTISTS ONCE THOUGHT PHOBOS MAY HAVE BEEN CREATED BY MARTIANS.

    In the late 1950s and early 60s, unusual orbital characteristics of Phobos led to speculations by astronomers that it might actually be hollow. Russian astrophysicist Iosif Samuilovich Shklovsky suggested a “thin sheet metal” structure for Phobos and this lead to even more speculation that the moon may be of artificial origin. Fred Singer, who at the time was science advisor to U.S. President Dwight D. Eisenhower, said of Shklovsky’s theory:
    "If the satellite is indeed spiralling inward as deduced from astronomical observation, then there is little alternative to the hypothesis that it is hollow and therefore Martian made."

    A 150-POUND PERSON WOULD WEIGH ABOUT 2 OUNCES ON PHOBOS

    This is because of the small size of the moon and its very weak gravity.

  2. #2
    Thailand Expat jabir's Avatar
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    great potential here, and we're still discovering new moons - most recently just last year. Fex, last I knew Jupiter had 62 moons, but today 79 and counting.

    Useful starting point for mindblowing moon stuff:
    https://en.wikipedia.org/wiki/Timeli...nd_their_moons

  3. #3
    'ello 'ello 'ello Luigi's Avatar
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    One of my 2 favourites.

    Europa.

    One of the Galilean Moons of Jupiter.




    Beneath the icy surface of Jupiter’s moon Europa is perhaps the most promising place to look for present-day environments suitable for life.
    Slightly smaller than Earth's Moon, Europa’s water-ice surface is crisscrossed by long, linear fractures. Like our planet, Europa is thought to have an iron core, a rocky mantle and an ocean of salty water. Unlike Earth, however, Europa’s ocean lies below a shell of ice probably 10 to 15 miles (15 to 25 kilometers) thick and has an estimated depth of 40 to 100 miles (60 to 150 kilometers).
    Europa is named for a woman abducted by the god Zeus in Greek mythology–Jupiter to the Romans.


    Overview

    Beneath the icy surface of Jupiter’s moon Europa is perhaps the most promising place to look for present-day environments suitable for life.
    Slightly smaller than Earth's Moon, Europa’s water-ice surface is crisscrossed by long, linear fractures. Like our planet, Europa is thought to have an iron core, a rocky mantle and an ocean of salty water. Unlike Earth, however, Europa’s ocean lies below a shell of ice probably 10 to 15 miles (15 to 25 kilometers) thick and has an estimated depth of 40 to 100 miles (60 to 150 kilometers).
    Europa is named for a woman abducted by the god Zeus in Greek mythology–Jupiter to the Romans.



    Europa orbits Jupiter every 3.5 days and is locked by gravity to Jupiter, so the same hemisphere of the moon always faces the planet. Because Europa's orbit is elliptical (slightly stretched out from circular), its distance from Jupiter varies, and the moon’s near side feels Jupiter’s gravity more strongly than its far side. The magnitude of this difference changes as Europa orbits, creating tides that stretch and relax the moon’s surface. Flexing from the tides creates the moon’s surface fractures. If Europa's ocean exists, it might also have volcanic or hydrothermal activity on the seafloor, supplying nutrients that could make the ocean suitable for living things.


    Based on the small number of observable craters, the surface of this moon appears to be no more than 40 to 90 million years old, which is youthful in geologic terms (the surface of Callisto, another of Jupiter’s moons, is estimated to be a few billion years old). Along Europa's many fractures, and in splotchy patterns across its surface, is a reddish-brown material whose composition is not known, but may hold clues to the moon's potential as a habitable world.


    NASA's Galileo spacecraft explored the Jupiter system from 1995 to 2003 and made numerous flybys of Europa. Galileo revealed strange pits and domes that suggest Europa’s surface ice could be slowly turning over, or convecting, due to heat from below. Galileo also found regions called "chaos terrain," where broken, blocky landscapes were covered in the mysterious reddish material. In 2011, scientists studying Galileo data proposed that chaos terrains could be places where the surface collapsed above lens-shaped lakes embedded within the ice.


    In 2013, NASA announced that researchers using the Hubble Space Telescope found evidence that Europa might be actively venting water into space, which would mean the moon is geologically active in the present day. If confirmed by follow-up observations, the plumes of water could be studied by future spacecraft similar to how the Cassini spacecraft sampled the plume of Enceladus.
    One of the most important measurements made by the Galileo mission showed how Jupiter's magnetic field was disrupted in the space around Europa. The measurement strongly implied that a special type of magnetic field is being created (induced) within Europa by a deep layer of some electrically conductive fluid beneath the surface. Based on Europa's icy composition, scientists think the most likely material to create this magnetic signature is a global ocean of salty water.


    Scientists will begin studying Europa anew with the Europa Clipper mission. Scheduled to launch in the 2020s, Europa Clipper would arrive at Jupiter several years later and try to see whether the icy moon could harbor conditions suitable for life. The radiation-tolerant spacecraft will perform 45 flybys of Europa at altitudes varying from 1,675 miles to 16 miles (2,700 kilometers to 25 kilometers) from a long, looping orbit around Jupiter.


    Clipper’s instruments will include cameras and spectrometers to produce high-resolution images of Europa's surface and determine its composition. An ice-penetrating radar will determine the thickness of the moon's icy shell and search for subsurface lakes similar to those beneath Antarctica. The mission will also carry a magnetometer to measure strength and direction of the moon's magnetic field, which will allow scientists to determine the depth and salinity of its ocean.



    Size compared to Earth, and the amount of water on both.









    There's probably alien life around those hydro-thermal vents.

  4. #4
    Valve Master
    Latindancer's Avatar
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    Crikey....Phobos has had something big smash into it, at some stage. It's got scarring like the remnants of some Teakdoor feud...

  5. #5
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    NamPikToot's Avatar
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    Nice one Lu, love this stuff.

  6. #6
    Thailand Expat

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    Quote Originally Posted by Luigi View Post
    There's probably alien life around those hydro-thermal vents.
    Potentially. "Probably" is a bit optimistic. Or naive.

  7. #7
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    Don't forget the ones orbiting Wallmarts all around USA, USA, USA!


  8. #8
    'ello 'ello 'ello Luigi's Avatar
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    One a bit closer to home.



    One of my own shots with seas, craters and Apollo landing sites crayoned on.



    How the Moon was formed.



    Around 4.5 billion years ago Theia came along to join the party.

    Changing the tilt of the Earth's axis and giving us our seasons.






    Surface Temperature:

    -233 to 123 C

    The rise and fall of the tides on Earth is caused by the Moon.


    • There are two bulges in the Earth due to the gravitational pull that the Moon exerts; one on the side facing the Moon, and the other on the opposite side that faces away from the Moon, The bulges move around the oceans as the Earth rotates, causing high and low tides around the globe.



    Australians, and other dodgy southern hemispherians see the Moon upside down.




  9. #9
    'ello 'ello 'ello Luigi's Avatar
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    One a bit further out.

    Charon.

    The largest of Pluto's moons.



    At almost half the size of Pluto, the largest moon in the solar system compared to the parent body.

    Not that it is orbiting Pluto.

    They are so close and similar in size that they orbit a barycenter, a point between the two bodies.



    At half the size of Pluto, Charon is the largest of Pluto's moons and the largest known satellite relative to its parent body. Pluto-Charon is our solar system's only known double planetary system. The same surfaces of Charon and Pluto always face each other, a phenomenon called mutual tidal locking. Charon orbits Pluto every 6.4 Earth days.



    The dance, from 50 million Km or so away.


    In Depth

    Charon is almost half the size of Pluto. The little moon is so big that Pluto and Charon are sometimes referred to as a double dwarf planet system. The distance between them is 19,640 km (12,200 miles).


    Charon's orbit around Pluto takes 6.4 Earth days, and one Pluto rotation (a Pluto day) takes 6.4 Earth days. Charon neither rises nor sets, but hovers over the same spot on Pluto's surface, and the same side of Charon always faces Pluto―this is called tidal locking.



    • Charon MAY have ‘ice volcanoes’.
      Observations made by ground-based observers at the Gemini Observatory in Hawaii determined that Charon MAY have ice-particle geysers, a form of cryovolcanism.

  10. #10
    Thailand Expat Dillinger's Avatar
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    Bet she got it with that teenage lutant hero wand

  11. #11
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    Any simple hint how to remember whether the Moon is either Waxing or Waning when looking on the sky?

    In some languages there are words to remember beginning with "D" for Waxing Crescent and "C" for Waning Crescent. Any such words in English?



  12. #12
    Thailand Expat Dillinger's Avatar
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    The Vialli twins




  13. #13
    'ello 'ello 'ello Luigi's Avatar
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    ^

  14. #14
    'ello 'ello 'ello Luigi's Avatar
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    Titan.

    The largest moon of Saturn and second largest in the Solar System. Larger than the planet Mercury and 50% larger than our Moon.

    The only body in space, besides Earth, with stable bodies of surface liquid.



    Unfortunately the rivers and lakes aren't water, but liquid methane (boiling point -161 degrees Celsius. )




    The surface of Titan is one of the most Earthlike places in the solar system, albeit at vastly colder temperatures and with different chemistry. Here it is so cold (-290 degrees Fahrenheit or -179 degrees Celsius) that water ice plays the role of rock. Titan may have volcanic activity as well, but with liquid water “lava” instead of molten rock. Titan’s surface is sculpted by flowing methane and ethane, which carves river channels and fills great lakes with liquid natural gas. No other world in the solar system, aside from Earth, has that kind of liquid activity on its surface.


    Vast regions of dark dunes stretch across Titan’s landscape, primarily around the equatorial regions. The "sand" in these dunes is composed of dark hydrocarbon grains thought to look something like coffee grounds. In appearance, the tall, linear dunes are not unlike those seen in the desert of Namibia in Africa. Titan has few visible impact craters, meaning its surface must be relatively young and some combination of processes erases evidence of impacts over time. Earth is similar in that respect as well; craters on our planet are erased by the relentless forces of flowing liquid (water, in Earth's case), wind, and the recycling of the crust via plate tectonics. These forces are present on Titan as well, in modified forms. In particular, tectonic forces—the movement of the ground due to pressures from beneath—appear to be at work on the icy moon, although scientists do not see evidence of plates like on Earth.
    Atmosphere

    Our solar system is home to more than 150 moons, but Titan is unique in being the only moon with a thick atmosphere. At the surface of Titan, the atmospheric pressure is about 60 percent greater than on Earth—roughly the same pressure a person would feel swimming about 50 feet (15 meters) below the surface in theocean on Earth. Because Titan is less massive than Earth, its gravity doesn't hold onto its gaseous envelope as tightly, so the atmosphere extends to an altitude 10 times higher than Earth's—nearly 370 miles (600 kilometers) into space.
    Titan's atmosphere is mostly nitrogen (about 95 percent) and methane (about 5 percent)



    Liquid methane seas.

  15. #15
    Thailand Expat jabir's Avatar
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    good stuff!

  16. #16
    Utopian Expat
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    Interesting read Lulu.

    Reminds me to have a trip out here...



    Her Royal Highness Princess Maha Chakri Sirindhorn of Thailand yesterday (5 July), visited Jodrell Bank Observatory to celebrate the close links between her country and The University of Manchester in astronomy.
    On her visit, Her Royal Highness – who is a keen astronomer – met scientists from the University’s School of Physics & Astronomy who are working closely with Thai researchers on joint projects and heard about historic links between the University and the Royal Family which stretch back to an 1875 expedition to observe a solar eclipse.
    She toured the observatory, including the iconic Lovell Telescope and the Jodrell Bank Discovery Centre, which welcomes 185,000 visitors each year, including 26,000 school pupils on educational visits.
    She also visited the headquarters of the Square Kilometre Array, an international effort to build the world’s largest radio telescope over two sites in South Africa and Australia.
    One of the current collaborations Her Royal Highness heard about was with The National Astronomical Research Institute of Thailand (NARIT). The Capacity Building for Thai Radio Astronomy NARIT-STFC Newton Fund Collaboration is led by the University of Hertfordshire with extensive involvement from Jodrell Bank and funding from the Science and Technologies Funding Council. It aims to provide training and technical support for the Thai National Radio Observatory Astronomy.

    https://www.manchester.ac.uk/discove...k-observatory/



    Last edited by Chittychangchang; 06-03-2019 at 02:22 AM.

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