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NASA's Hubble Observations Suggest Underground Ocean on Jupiter's Largest Moon


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Nearly 500 million miles from the Sun lies a moon orbiting Jupiter that is slightly larger than the planet Mercury and may contain more water than all of Earth's oceans. Temperatures are so cold, though, that water on the surface freezes as hard as rock and the ocean lies roughly 100 miles below the crust. Nevertheless, where there is water there could be life as we know it. Identifying liquid water on other worlds — big or small — is crucial in the search for habitable planets beyond Earth. Though the presence of an ocean on Ganymede has been long predicted based on theoretical models, NASA's Hubble Space Telescope found the best evidence for it. Hubble was used to watch aurorae glowing above the moon's icy surface. The aurorae are tied to the moon's magnetic field, which descends right down to the core of Ganymede. A saline ocean would influence the dynamics of the magnetic field as it interacts with Jupiter's own immense magnetic field, which engulfs Ganymede. Because telescopes can't look inside planets or moons, tracing the magnetic field through aurorae is a unique way to probe the interior of another world.

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    • By NASA
      Skywatching Skywatching Home Eclipses What’s Up Explore the Night Sky Night Sky Network More Tips and Guides FAQ 24 Min Read The Next Full Moon Will Be the Last of Four Consecutive Supermoons
      Guardians of Traffic statue in Cleveland, Ohio, in front of the supermoon that was visible on Sept. 17, 2024. On this day, the full moon was a partial lunar eclipse; a supermoon; and a harvest moon. Credits:
      NASA/GRC/Sara Lowthian-Hanna The Next Full Moon is a Supermoon; the Beaver, Frost, Frosty, or Snow Moon; Kartik Purnima; Loy Krathong; the Bon Om Touk (”Boat Racing Festival”) Moon, the Tazaungdaing Festival Moon; and Ill Poya.
      The next full Moon will be Friday afternoon, November 15, 2024, at 4:29 PM EST. This will be early Saturday morning from Kamchatka and Fiji Time eastwards to the International Date Line. The Pleiades star cluster will appear near the full Moon. The Moon will appear full for about 3 days around this time, from a few hours before sunrise on Thursday morning to a few hours before sunrise on Sunday morning.
      This full Moon will be the last of four consecutive supermoons, slightly closer and brighter than the first of the four in mid-August.
      The Maine Farmers’ Almanac began publishing Native American names for full Moons in the 1930s. Over time these names have become widely known and used. According to this almanac, as the full Moon in November this is the Beaver Moon, the Frost or Frosty Moon, or the Snow Moon. For the Beaver Moon, one interpretation is that mid-Fall was the time to set beaver traps before the swamps freeze to ensure a supply of warm winter furs. Another interpretation suggests that the name Beaver Moon came from how active the beavers are in this season as they prepare for winter. The Frost, Frosty, or Snow Moon names come from the frosts and early snows that begin this time of year, particularly in northeastern North America.
      This is Kartik Purnima (the full Moon of the Hindu lunar month of Kartik) and is celebrated by Hindus, Jains, and Sikhs (each for different reasons).
      In Thailand and nearby countries this full Moon is Loy Krathong, a festival that includes decorating baskets and floating them on a river.
      In Cambodia this full Moon corresponds with the 3-day Bon Om Touk (“Boat Racing Festival”), the Cambodian Water Festival featuring dragon boat races.
      In Myanmar this is the Tazaungdaing Festival, a festival that predates the introduction of Buddhism and includes the launching of hot air balloons (sometimes flaming or laden with fireworks).
      In Sri Lanka this is Ill (or Il) Poya, commemorating the Buddha’s ordination of sixty disciples as the first Buddhist missionaries.
      In many traditional Moon-based calendars the full Moons fall on or near the middle of each month. This full Moon is near the middle of the tenth month of the Chinese year of the Dragon, Marcheshvan in the Hebrew calendar, a name often shortened to Cheshvan or Heshvan, and Jumādā al-ʾŪlā, the fifth month of the Islamic year.
      As usual, the wearing of suitably celebratory celestial attire is encouraged in honor of the full Moon. Get ready for winter, visit a local river (particularly if there are any festivals or boat races), but please don’t launch flaming hot air balloons filled with fireworks (some online videos make it quite clear why this is a bad idea), especially in areas subject to wildfires!
      The next month or two should be a great time for Jupiter and Saturn watching. Both will continue to shift westward each night, gradually making them easier to see earlier in the evening sky.
      Gordon Johnston
      Retired NASA Program Executive
      As for other celestial events between now and the full Moon after next (with specific times and angles based on the location of NASA Headquarters in Washington, DC):
      As Autumn continues the daily periods of sunlight continue shortening.
      On Friday, November 15, (the day of the full Moon), morning twilight will begin at 5:51 AM EST, sunrise will be at 6:51 AM, solar noon will be at 11:53 AM when the Sun will reach its maximum altitude of 32.4 degrees, sunset will be at 4:54 PM, and evening twilight will end at 5:55 PM.
      Our 24-hour clock is based on the average length of the solar day. The day of the winter solstice is sometimes called the “shortest day of the year” (because it has the shortest period of sunlight). But it could also be called the “longest day of the year” because the longest solar day is on or just after the solstice. Because the solar days are longer, the earliest sunset of the year occurs before the solstice and the latest sunrise of the year (ignoring Daylight Savings Time) occurs after the solstice. For the Washington, DC area, the sunsets on Friday and Saturday, December 6 and 7, 2024, are tied for the earliest sunsets. On Friday, morning twilight will begin at 6:10 AM EST, sunrise will be at 7:13 AM, solar noon will be at 11:59 AM when the Sun will reach its maximum altitude of 28.5 degrees, sunset will be at 4:45:50 PM, and evening twilight will end at 5:49 PM. On Saturday, morning twilight will begin at 6:11 AM EST, sunrise will be at 7:14 AM, solar noon will actually be at noon (12:00 PM) when the Sun will reach its maximum altitude of 28.4 degrees, sunset will be at 4:45:50 PM, and evening twilight will end at 5:49 PM.
      By Sunday, December 15, (the day of the full Moon after next), morning twilight will begin at 6:16 AM EST, sunrise will be at 7:20 AM, solar noon will be at 12:04 PM when the Sun will reach its maximum altitude of 27.8 degrees, sunset will be at 4:47 PM, and evening twilight will end at 5:51 PM.
      The next month or two should be a great time for Jupiter and Saturn watching, especially with a backyard telescope. Saturn was at its closest and brightest on September 7 and is high in the southern sky as evening twilight ends. Jupiter will be shifting into the evening sky during this lunar cycle. On November 15 Jupiter will be rising about a half hour after evening twilight ends. Jupiter will be at its closest and brightest on December 7, rising around sunset and setting around sunrise. By the full Moon after next on December 15, Jupiter will be 19 degrees above the horizon as evening twilight ends. Both Jupiter and Saturn will continue to shift westward each night, gradually making them easier to see earlier in the evening sky (and friendlier for backyard stargazing, especially if you have young ones with earlier bedtimes). With clear skies and a telescope you should be able to see Jupiter’s four bright moons, Ganymede, Callisto, Europa, and Io, noticeably shifting positions in the course of an evening. For Saturn, you should be able to see Saturn’s rings and its bright moon Titan. The rings are appearing thinner and will be edge-on to the Earth in March 2025. We won’t get the “classic” view of Saturn showing off its rings until 2026.
      Comets
      Of the two comets described in my last Moon Missive, one remains visible through large binoculars or a telescope during this lunar cycle. The sungrazing Comet C/2024 S1 (ATLAS) disintegrated during its very close pass by the Sun and is no longer visible. Comet C/2023 A3 (Tsuchinshan-ATLAS) will be in the evening sky, fading from visual magnitude 8 to 10.3 as it moves away from the Earth and Sun.
      In addition, comet 33P/LINEAR should be visible with large binoculars or a telescope in November and December, shining at about magnitude 10 around its perihelion on November 29 and closest approach to Earth on December 9. The next comet that we anticipate might be visible to the unaided eye is C/2024 G3 (ATLAS), which will reach its closest to the Sun and Earth in mid January 2025. It is another sungrazing comet that might put on a good show or might break apart and vanish.
      Meteor Showers
      Unfortunately, one of the three major meteor showers of the year, the Geminids (004 GEM), will peak the morning of December 14, with the light of the nearly full Moon interfering. According to the International Meteor Organization, observers south of about 30 degrees north might be able to see these meteors for an hour or so between moonset and the first light of dawn (although the radiant for this meteor shower is at 33 degrees north latitude, so observers too far south of the equator will also have limited visibility). In a good year, this shower can produce 150 visible meteors per hour under ideal conditions, but this will not be a good year. For the Washington, DC area the MeteorActive app predicts that at about 2 AM EST on the morning of December 14, under bright suburban sky conditions, the peak rate from the Geminids and all other background sources might reach 20 meteors per hour.
      If the weather cooperates by being clear with no clouds or hazes and you do go looking for meteors, try to find a place as far as possible from light sources that has a clear view of a wide expanse of the sky. Give your eyes plenty of time to adapt to the dark. Your color vision (cone cells), concentrated in the center of your field of view, will adapt to darkness in about 10 minutes. Your more sensitive night vision rod cells will continue to improve for an hour or more (with most of the improvement in the first 35 to 45 minutes). The more sensitive your eyes are, the more chance you will have of seeing meteors. Since some meteors are faint, you will tend to see more meteors from the “corner of your eye.” Even a short exposure to light (from passing car headlights, etc.) will start the adaptation over again (so no turning on a light or your cell phone to check what time it is).
      In addition, a number of relatively minor meteor showers will peak during this lunar cycle. The light of the waning Moon will interfere with the Leonids (013 LEO) on November 17, α-Monocerotids (246 AMO) on November 21, and November Orionids (250 NOO) on November 28. The Phoenicids (254 PHO), best seen from the Southern Hemisphere, may peak around December 1. Models predict low rates and faint meteors this year but not much is known about this meteor shower. Most years the rates are low, but as reported by the International Meteor Organization, significant activity was observed in 2014. Once, in 1956, the Phoenicids reached an estimated rate of 100 visible meteors per hour. Another Southern Hemisphere shower is the Puppid-Velids (301 PUP), expected to peak sometime around December 4 at about 10 meteors per hour (under ideal conditions). The Monocerotids (019 MON) and σ-Hydrids (016 HYD) are both expected to peak on December 9 at 3 meteors per hour and 7 meteors per hour, respectively. These rates are low enough that seeing them from our light-polluted urban areas will be unlikely.
      Evening Sky Highlights
      On the evening of Friday, November 15 (the evening of the full Moon), as twilight ends (at 5:55 PM EST), the rising Moon will be 14 degrees above the east-northeastern horizon with the Pleiades star cluster 5 degrees to the lower left. The brightest planet in the sky will be Venus at 12 degrees above the southwestern horizon. Next in brightness will be Mercury at less than a degree above the west-southwestern horizon. Saturn will be 38 degrees above the south-southeastern horizon. Comet C/2023 A3 (Tsuchinshan-ATLAS) will be 39 degrees above the west-southwestern horizon, with its current brightness curve predicting it will have faded to magnitude 8, too faint to see with the unaided eye. The bright star closest to overhead will be Deneb at 79 degrees above the northwestern horizon. Deneb (visual magnitude 1.3) is the 19th brightest star in our night sky and is the brightest star in the constellation Cygnus the swan. One of the three bright stars of the “Summer Triangle” (along with Vega and Altair). Deneb is about 20 times more massive than our Sun but has used up its hydrogen, becoming a blue-white supergiant about 200 times the diameter of the Sun. If Deneb were where our Sun is, it would extend to about the orbit of the Earth. Deneb is about 2,600 light years from us.
      As this lunar cycle progresses, Saturn and the background of stars will appear to shift westward each evening (as the Earth moves around the Sun). Bright Venus will shift to the left and higher in the sky along the southwestern horizon. Mercury, shining brighter than Saturn, will initially shift left along the southwestern horizon until November 19, after which it will shift to the right. On November 22 Jupiter will join the planets Venus, Mercury and Saturn in the sky as twilight ends, shining brighter than Mercury. November 24 will be the last evening Mercury will be above the horizon as evening twilight ends, although it will remain visible in the glow of dusk for a few more evenings as it dims and shifts towards its passage between the Earth and the Sun on December 5. Jupiter will be at its closest and brightest for the year on December 7. The waxing Moon will pass by Venus on December 4, Saturn on December 7, and the Pleiades on December 13.
      By the evening of Saturday, December 14 (the start of the night of the December 15 full Moon), as twilight ends (at 5:50 PM EST), the rising Moon will be 19 degrees above the east-northeastern horizon with bright planet Jupiter 6 degrees to the right and the bright star Aldebaran father to the right. The brightest planet visible will be Venus at 21 degrees above the southwestern horizon. Next in brightness will be Jupiter. Saturn will be 43 degrees above the southern horizon. The bright star closest to overhead will still be Deneb at 61 degrees above the west-northwestern horizon.
      Morning Sky Highlights
      On the morning of Friday, November 15 (the morning of the full Moon after next), as twilight begins (at 5:51 AM EST), the setting full Moon will be 7 degrees above the west-northwestern horizon. The brightest planet in the sky will be Jupiter at 35 degrees above the western horizon. Mars will be at 68 degrees above the southwestern horizon. Comet C/2024 S1 (ATLAS) will not be visible, even with a telescope, as it broke apart into pieces too small to see as it passed its closest to the Sun on October 28. The bright star appearing closest to overhead will be Pollux at 69 degrees above the west-southwestern horizon (higher than Mars by about a half degree). Pollux is the 17th brightest star in our night sky and the brighter of the twin stars in the constellation Gemini. It is an orange tinted star about 34 lightyears from Earth. Pollux is not quite twice the mass of our Sun but about 9 times the diameter and 33 times the brightness.
      As this lunar cycle progresses, Jupiter, Mars, and the background of stars will appear to shift westward each evening, with Mars passing near the Beehive star cluster in early December. The waning Moon will pass by the Pleiades star cluster on November 16, Jupiter on November 17, Mars and Pollux on November 20, appear on the other side of Mars on November 21, Regulus on November 22 and 23, and Spica on November 27 (passing in front of Spica for parts of the USA and Canada). Jupiter will be at its closest and brightest on December 7, rising around sunset and setting around sunrise. December 12 will be the first morning Mercury will be above the east-southeastern horizon as morning twilight begins, though it will be visible in the glow of dawn for a few days before.
      By the morning of Sunday, December 15 (the morning of the full Moon after next), as twilight begins (at 6:16 AM EST), the setting full Moon will be 15 degrees above the west-northwestern horizon. The brightest planet in the sky will be Jupiter, appearing below the Moon at 5 degrees above the horizon. Second in brightness will be Mars at 46 degrees above the western horizon, then Mercury at 4 degrees above the east-southeastern horizon. The bright star appearing closest to overhead will be Regulus at 55 degrees above the southwestern horizon, with Arcturus a close second at 52 degrees above the east-southeastern horizon. Regulus is the 21st brightest star in our night sky and the brightest star in the constellation Leo the lion. The Arabic name for Regulus translates as “the heart of the lion.” Although we see Regulus as a single star, it is actually four stars (two pairs of stars orbiting each other). Regulus is about 79 light years from us. Arcturus is the brightest star in the constellation Boötes the herdsman or plowman and the 4th brightest star in our night sky. It is 36.7 light years from us. While it has about the same mass as our Sun, it is about 2.6 billion years older and has used up its core hydrogen, becoming a red giant 25 times the size and 170 times the brightness of our Sun. One way to identify Arcturus in the night sky is to start at the Big Dipper, then follow the arc of the handle as it “arcs towards Arcturus.”
      Detailed Daily Guide
      Here for your reference is a day-by-day listing of celestial events between now and the full Moon on December 15, 2024. The times and angles are based on the location of NASA Headquarters in Washington, DC, and some of these details may differ for where you are (I use parentheses to indicate times specific to the DC area). If your latitude is significantly different than 39 degrees north (and especially for my Southern Hemisphere readers), I recommend using an astronomy app set for your location or a star-watching guide from a local observatory, news outlet, or astronomy club.
      Thursday morning, November 14, at 6:18 EST, the Moon will be at perigee, its closest to the Earth for this orbit.
      As mentioned above, the full Moon will be Friday afternoon, November 15, 2024, at 4:29 PM EST. This will be early Saturday morning from Kamchatka and Fiji Time eastwards to the International Date Line. It will be the last of four consecutive supermoons. The Pleiades star cluster will appear near the full Moon. The Moon will appear full for about 3 days around this time, from a few hours before sunrise Thursday morning to a few hours before sunrise Sunday morning.
      Friday evening into Saturday morning, November 15 to 16, the Pleiades star cluster will appear near the full Moon. This may best be viewed with binoculars, as the brightness of the full Moon may make it hard to see the stars in this star cluster. As evening twilight ends (at 5:55 PM EST), the Pleiades will appear 5 degrees to the lower left of the full Moon. By the time the Moon reaches its highest for the night (Saturday morning at 12:07 AM), the Pleiades will be 2 degrees to the upper left. The Moon will pass in front of the Pleiades in the early morning hours. By the time morning twilight begins (at 5:52 AM) the Pleiades will be a degree to the lower right of the Moon.
      Saturday, November 16, will be when the planet Mercury reaches its greatest angular separation from the Sun as seen from the Earth for this apparition (called greatest elongation). Because the angle between the line from the Sun to Mercury and the line of the horizon changes with the seasons, the date when Mercury and the Sun are farthest apart as seen from the Earth is not always the same as when Mercury appears highest above the southwestern horizon as evening twilight ends, which will occur three evenings later, on November 19.
      Saturday night into Sunday morning, November 16 to 17, the planet Uranus will be at its closest and brightest for the year, called “opposition” because on Saturday night it will be opposite the Earth from the Sun. At opposition Uranus can be bright enough to see with the unaided eye (under very clear, dark sky conditions). From our light-polluted urban locations you will need binoculars or a telescope.
      Also on Saturday night into Sunday morning, November 16 to 17, the planet Jupiter will appear near the full Moon. As Jupiter rises on the east-northeastern horizon (at 6:14 PM EST) it will be 10 degrees to the lower left of the Moon. The Moon will reach its highest for the night about 7 hours later (at 1:09 AM), with Jupiter 7.5 degrees to the lower left. By the time morning twilight begins (at 5:52 AM) Jupiter will be 6 degrees to the left of the Moon.
      Tuesday night into Wednesday morning, November 19 to 20, the bright star Pollux and the bright planet Mars will appear near the waning gibbous Moon. As the Moon rises on the northeastern horizon (at 8:20 PM EST), Pollux will be 2.5 degrees to the upper left of the Moon. By the time the Moon reaches its highest in the sky (at 4:11 AM) Pollux will be 5 degrees to the upper right of the Moon, with Mars 7.5 degrees to the lower left of the Moon, such that these three appear aligned. By the time morning twilight begins (at 5:55 AM) Mars will be 7 degrees to the upper left and Pollux 5.5 degrees to the lower right.
      Wednesday night into Thursday morning, November 20 to 21, the waning gibbous Moon will have shifted to the other side of Mars. As the Moon rises on the east-northeastern horizon (at 9:29 PM EST) Mars will be 4 degrees to the upper right of the Moon. By the time the Moon reaches its highest for the night (at 5:03 AM) Mars will be 7 degrees to the right of the Moon. Morning twilight will begin less than an hour later (at 5:56 AM) with Mars 7 degrees to the lower right of the Moon.
      Friday evening, November 22, will be the first evening the bright planet Jupiter will be above the east-northeastern horizon as evening twilight ends (at 5:51 PM EST).
      Also on Friday evening, the waning Moon will appear half-full as it reaches its last quarter at 8:28 PM EST (when we can’t see it).
      Friday night into Saturday morning, November 22 to 23, the bright star Regulus will appear near the waning half-Moon. As Regulus rises on the east-northeastern horizon (at 11:29 PM EST) it will be 9 degrees below the Moon, with Mars farther to the upper right and Pollux beyond Mars. By the time the Moon reaches its highest for the night (at 5:49 AM) Regulus will be 7 degrees to the lower left, and morning twilight will begin 8 minutes later (at 5:57 AM).
      Saturday night into Sunday morning, November 23 to 24, the waning crescent Moon will have shifted to the other side of Regulus. When the Moon rises on the east-northeastern horizon (at 11:38 PM EST) Regulus will be 4 degrees to the upper right of the Moon. The pair will separate as the night progresses. By the time morning twilight begins (at 5:58 AM) Regulus will be 6.5 degrees to the upper right of the Moon.
      Sunday evening, November 24, will be the last evening the planet Mercury will be above the west-southwestern horizon as evening twilight ends, although it should remain visible in the glow of dusk before twilight ends for a few more evenings as it dims and shifts towards its passage between the Earth and the Sun on December 5.
      Tuesday morning, November 26, at 6:57 AM EST, the Moon will be at apogee, its farthest from the Earth for this orbit.
      On Wednesday morning, November 27, the bright star Spica will appear near the waning crescent Moon. As Spica rises on the east-southeastern horizon (at 3:41 AM EST) it will be a degree below the Moon. As morning progresses the Moon will shift towards Spica, and for much of the Eastern USA and Canada the Moon will block Spica from view. See http://www.lunar-occultations.com/iota/bstar/1127zc1925.htm for a map and information on the areas that will be able to see this eclipse. Times will vary by location, but for the Washington, DC area, Spica will vanish behind the illuminated limb of the Moon at 5:34 AM and the Moon will still be blocking Spica from sight as morning twilight begins at 6:02 AM.
      Early Sunday morning, December 1, at 1:22 AM EST, will be the new Moon, when the Moon passes between the Earth and the Sun and will not be visible from the Earth.
      The day of or the day after the New Moon marks the start of the new month for most moon-based calendars. The eleventh month of the Chinese year of the Dragon starts on Sunday, December 1. Sundown on Sunday, December 1, marks the start of Kislev in the Hebrew calendar. Hanukkah will begin towards the end of Kislev. In the Islamic calendar the months traditionally start with the first sighting of the waxing crescent Moon. Many Muslim communities now follow the Umm al-Qura Calendar of Saudi Arabia, which uses astronomical calculations to start months in a more predictable way. Using this calendar, sundown on Sunday, December 1, will probably mark the beginning of Jumādā ath-Thāniyah, also known as Jumādā al-ʾĀkhirah.
      Wednesday evening, December 4, the bright planet Venus will appear 3 degrees to the upper right of the waxing crescent Moon. The Moon will be 15 degrees above the southwestern horizon as evening twilight ends (at 5:49 PM EST). The Moon will set 2 hours later (at 7:46 PM).
      Thursday evening, December 5, the planet Mercury will be passing between the Earth and the Sun as seen from the Earth, called inferior conjunction. Planets that orbit inside of the orbit of Earth can have two types of conjunctions with the Sun, inferior (when passing between the Earth and the Sun) and superior (when passing on the far side of the Sun as seen from the Earth). Mercury will be shifting from the evening sky to the morning sky and will begin emerging from the glow of dawn on the eastern horizon in less than a week.
      Saturday afternoon, December 7, the planet Jupiter will be at its closest and brightest for the year, called “opposition” because it will be opposite the Earth from the Sun, effectively a “full” Jupiter. Jupiter will be 12 degrees above the east-northeastern horizon as evening twilight ends (at 5:49 PM EST), will reach its highest in the sky right around midnight (11:59 PM), and will be 11 degrees above the west-northwestern horizon as morning twilight begins (Sunday morning at 6:11 AM). Only planets that orbit farther from the Sun than the Earth can be seen at opposition.
      Saturday evening, December 7, the planet Saturn will appear to the upper left of the waxing crescent Moon. They will be 6 degrees apart as evening twilight ends (at 5:49 PM EST). Saturn will appear to shift clockwise and closer to the Moon, so that by the time the Moon sets 5.5 hours later (at 11:18 PM) Saturn will be 3.5 degrees above the Moon on the west-southwestern horizon. For a swath in the Pacific Ocean off the coast of Asia the Moon will actually block Saturn from view, see http://lunar-occultations.com/iota/planets/1208saturn.htm for a map and information on the locations that can see this eclipse.
      Sunday morning, December 8, the Moon will appear half-full as it reaches its first quarter at 10:27 AM EST (when we can’t see it).
      Thursday morning, December 12, will be the first morning the planet Mercury will be above the east-southeastern horizon as morning twilight begins (at 6:14 AM EST).
      Thursday morning, December 12, at 8:18 AM EST, the Moon will be at perigee, its closest to the Earth for this orbit.
      Friday evening into Saturday morning, December 13 to 14, the Pleiades star cluster will appear near the full Moon. This may best be viewed with binoculars, as the brightness of the full Moon may make it hard to see the stars in this star cluster. As evening twilight ends (at 5:50 PM EST), the Pleiades will appear 4 degrees to the upper right of the full Moon. By the time the Moon reaches its highest for the night (at 10:49 PM), the Pleiades will be 6 degrees to the right. By about 2 AM the Pleiades will be 8 degrees to the lower right of the Moon and they will continue to separate as the morning progresses.
      As mentioned above, one of the three major meteor showers of the year, the Geminids (004 GEM), will peak Saturday morning, December 14. The light of the nearly full Moon will interfere. In a good year, this shower can produce 150 visible meteors per hour under ideal conditions, but this will not be a good year. For the Washington, DC area the MeteorActive app predicts that at about 2 AM EST on the morning of December 14, under bright suburban sky conditions, the peak rate from the Geminids and all other background sources might reach 20 meteors per hour. See the meteor summary above for suggestions for meteor viewing.
      Saturday morning, December 14, the full Moon, the bright planet Jupiter, and the bright star Aldebaran will form a triangle. As Aldebaran sets on the west-northwestern horizon (at 6:10 AM EST) it will be 9 degrees to the lower left of the Moon with Jupiter 7 degrees to the upper left of the Moon. Morning twilight will begin 6 minutes later.
      Saturday evening, December 15, the full Moon will have shifted to the other side of Jupiter. Jupiter will be 6 degrees to the right of the Moon as evening twilight ends (at 5:50 PM EST) and the pair will separate as the night progresses.  
      The full Moon after next will be Sunday morning, December 15, 2024, at 4:02 AM EST. This will be Saturday evening from Alaska Time westwards to the International Date Line. The Moon will appear full for about 3 days around this time, from Friday evening through Monday morning, making this a full Moon weekend.
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    • By NASA
      MuSat2 at Vandenberg Air Force Base, prior to launch. MuSat2 leverages a dual-frequency science antenna developed with support from NASA to measure phenomena such as ocean wind speed. Muon Space A science antenna developed with support from NASA’s Earth Science Technology Office (ESTO) is now in low-Earth orbit aboard MuSat2, a commercial remote-sensing satellite flown by the aerospace company Muon Space. The dual-frequency science antenna was originally developed as part of the Next Generation GNSS Bistatic Radar Instrument (NGRx). Aboard MuSat2, it will help measure ocean surface wind speed—an essential data point for scientists trying to forecast how severe a burgeoning hurricane will become.
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      Ruf designed the entire NGRx system to be an updated version of the sensors on NASA’s Cyclone Global Navigation Satellite System (CYGNSS), another technology he developed with support from ESTO. Since 2016, data from CYGNSS has been a critical resource for people dedicated to forecasting hurricanes.
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      Hurricane Ida, as seen from the International Space Station. NASA-developed technology onboard MuSat2 will help supply the U.S. Air Force with critical data for producing reliable weather forecasts. NASA For Muon Space, this technology infusion has been helpful to the company’s business and science missions. Dallas Masters, Vice President of Muon’s Signals of Opportunity Program, explains that NASA’s investments in NGRx technology made it much easier to produce a viable commercial remote sensing satellite. According to Masters, “NGRx-derived technology allowed us to start planning a flight mission early in our company’s existence, based around a payload we knew had flight heritage.”
      Dyer agrees. “The fact that ESTO proves out these measurement approaches – the technology and the instrument, the science that you can actually derive, the products from that instrument – is a huge enabler for companies like ours, because we can adopt it knowing that much of the physics risk has been retired,” he said.
      Ultimately, this advanced antenna technology for measuring ocean surface wind speed will make it easier for researchers to turn raw data into actionable science products and to develop more accurate forecasts.
      “Information is absolutely precious. When it comes to forecast models and trying to understand what’s about to happen, you have to have as good an idea as you can of what’s already happening in the real world,” said oceanographer Lew Gramer, an Associate Scientist with the Cooperative Institute For Marine And Atmospheric Studies and NOAA’s Hurricane Research Division.
      Project Lead: Chris Ruf, University of Michigan
      Sponsoring Organizations: NASA’s Earth Science Technology Office and Muon Space
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      Details
      Last Updated Nov 12, 2024 Related Terms
      CYGNSS (Cyclone Global Navigation Satellite System) Earth Science Earth Science Division Earth Science Technology Office Oceans Science-enabling Technology Technology Highlights Explore More
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    • By NASA
      ESA/Hubble & NASA, O. Fox, L. Jenkins, S. Van Dyk, A. Filippenko, J. Lee and the PHANGS-HST Team, D. de Martin (ESA/Hubble), M. Zamani (ESA/Hubble) This NASA/ESA Hubble Space Telescope image features NGC 1672, a barred spiral galaxy located 49 million light-years from Earth in the constellation Dorado. This galaxy is a multi-talented light show, showing off an impressive array of different celestial lights. Like any spiral galaxy, shining stars fill its disk, giving the galaxy a beautiful glow. Along its two large arms, bubbles of hydrogen gas shine in a striking red light fueled by radiation from infant stars shrouded within. Near the galaxy’s center are some particularly spectacular stars embedded within a ring of hot gas. These newly formed and extremely hot stars emit powerful X-rays. Closer in, at the galaxy’s very center, sits an even brighter source of X-rays, an active galactic nucleus. This X-ray powerhouse makes NGC 1672 a Seyfert galaxy. It forms as a result of heated matter swirling in the accretion disk around NGC 1672’s supermassive black hole.
      See more images of NGC 1672.
      Image credit: ESA/Hubble & NASA, O. Fox, L. Jenkins, S. Van Dyk, A. Filippenko, J. Lee and the PHANGS-HST Team, D. de Martin (ESA/Hubble), M. Zamani (ESA/Hubble)
      View the full article
    • By NASA
      Hubble Space Telescope Home Hubble Captures a Galaxy with… Missions Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts E-books Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More Online Activities   2 min read
      Hubble Captures a Galaxy with Many Lights
      This NASA/ESA Hubble Space Telescope image captures the spiral galaxy NGC 1672 with a supernova. ESA/Hubble & NASA, O. Fox, L. Jenkins, S. Van Dyk, A. Filippenko, J. Lee and the PHANGS-HST Team, D. de Martin (ESA/Hubble), M. Zamani (ESA/Hubble)
      Download this image

      This NASA/ESA Hubble Space Telescope image features NGC 1672, a barred spiral galaxy located 49 million light-years from Earth in the constellation Dorado. This galaxy is a multi-talented light show, showing off an impressive array of different celestial lights. Like any spiral galaxy, shining stars fill its disk, giving the galaxy a beautiful glow. Along its two large arms, bubbles of hydrogen gas shine in a striking red light fueled by radiation from infant stars shrouded within. Near the galaxy’s center are some particularly spectacular stars embedded within a ring of hot gas. These newly formed and extremely hot stars emit powerful X-rays. Closer in, at the galaxy’s very center, sits an even brighter source of X-rays, an active galactic nucleus. This X-ray powerhouse makes NGC 1672 a Seyfert galaxy. It forms as a result of heated matter swirling in the accretion disk around NGC 1672’s supermassive black hole.
      Image Before/After Along with its bright young stars and X-ray core, a highlight of this image is the most fleeting and temporary of lights: a supernova, visible in just one of the six Hubble images that make up this composite. Supernova SN 2017GAX was a Type I supernova caused by the core-collapse and subsequent explosion of a giant star that went from invisible to a new light in the sky in just a matter of days. In the image above, the supernova is already fading and is visible as a small green dot just below the crook of the spiral arm on the right side. Astronomers wanted to look for any companion star that the supernova progenitor may have had — something impossible to spot beside a live supernova — so they purposefully captured this image of the fading supernova.
      Recently, NGC 1672 was also among a crop of galaxies imaged with the NASA/ESA/CSA James Webb Space Telescope, showing the ring of gas and the structure of dust in its spiral arms. The image below compares the Webb image with Hubble’s image.
      Image Before/After Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
      Claire Andreoli
      NASA’s Goddard Space Flight Center, Greenbelt, MD
      claire.andreoli@nasa.gov
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      Last Updated Nov 08, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
      Astrophysics Astrophysics Division Galaxies Goddard Space Flight Center Hubble Space Telescope Missions Spiral Galaxies Stars Supernovae The Universe Keep Exploring Discover More Topics From Hubble
      Hubble Space Telescope


      Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.


      Hubble’s Galaxies



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      View the full article
    • By NASA
      2 min read
      NASA-Funded Study Examines Tidal Effects on Planet and Moon Interiors
      NASA-supported scientists have developed a new method to compute how tides affect the interiors of planets and moons. Importantly, the new study looks at the effects of body tides on objects that don’t have a perfectly spherical interior structure, which is an assumption of most previous models.
      The puzzling, fascinating surface of Jupiter’s icy moon Europa looms large in this newly-reprocessed color view, made from images taken by NASA’s Galileo spacecraft in the late 1990s. This is the color view of Europa from Galileo that shows the largest portion of the moon’s surface at the highest resolution. NASA/JPL-Caltech/SETI Institute Body tides refer to the deformations experienced by celestial bodies when they gravitationally interact with other objects. Think of how the powerful gravity of Jupiter tugs on its moon Europa. Because Europa’s orbit isn’t circular, the crushing squeeze of Jupiter’s gravity on the moon varies as it travels along its orbit.  When Europa is at its closest to Jupiter, the planet’s gravity is felt the most. The energy of this deformation is what heats up Europa’s interior, allowing an ocean of liquid water to exist beneath the moon’s icy surface.
      “The same is true for Saturn’s moon Enceladus.” says co-author Alexander Berne of CalTech in Pasadena and an affiliate at NASA’s Jet Propulsion Laboratory in Southern California. “Enceladus has an ice shell that is expected to be much more non-spherically symmetric than that of Europa.”
      The body tides experienced by celestial bodies can affect how the worlds evolve over time and, in cases like Europa and Enceladus, their potential habitability for life as we know it. The new study provides a means to more accurately estimate how tidal forces affect planetary interiors.
      In this movie Europa is seen in a cutaway view through two cycles of its 3.5 day orbit about the giant planet Jupiter. Like Earth, Europa is thought to have an iron core, a rocky mantle and a surface ocean of salty water. Unlike on Earth, however, this ocean is deep enough to cover the whole moon, and being far from the sun, the ocean surface is globally frozen over. Europa’s orbit is eccentric, which means as it travels around Jupiter, large tides, raised by Jupiter, rise and fall. Jupiter’s position relative to Europa is also seen to librate, or wobble, with the same period. This tidal kneading causes frictional heating within Europa, much in the same way a paper clip bent back and forth can get hot to the touch, as illustrated by the red glow in the interior of Europa’s rocky mantle and in the lower, warmer part of its ice shell. This tidal heating is what keeps Europa’s ocean liquid and could prove critical to the survival of simple organisms within the ocean, if they exist. The giant planet Jupiter is now shown to be rotating from west to east, though more slowly than its actual rate. NASA/JPL-Caltech The paper also discusses how the results of the study could help scientists interpret observations made by missions to a variety of different worlds, ranging from Mercury to the Moon to the outer planets of our solar system.
      The study, “A Spectral Method to Compute the Tides of Laterally Heterogeneous Bodies,” was published in The Planetary Science Journal. 
      For more information on NASA’s Astrobiology Program, visit:
      https://science.nasa.gov/astrobiology
      -end-
      Karen Fox / Molly Wasser
      Headquarters, Washington
      202-358-1600
      karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov 
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      Last Updated Nov 07, 2024 Related Terms
      Astrobiology View the full article
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