Astronomers peering closely at images of Pluto have spotted what look like dunes on the surface of the former planet. They wouldn’t be sand dunes, but dunes of methane ice—an Earthly feature on a totally alien world.
Dunes don’t just happen—they require both tiny grains and some sort of force, like wind, to push them into shape. When New Horizons passed by Pluto back in 2015, it captured dune-looking features just beside a mountain range. It’s a testament not only to jut how interesting distant cosmic objects can be, but how far humans have come in our ability to observe rocks in space.
“The best imagery prior to New Horizons was 12 pixels across for the whole dwarf planet,” study author Matt Telfer from Plymouth University in the United Kingdom told Gizmodo. “What we have now is evidence of a diverse, dynamic, and active geological surface. We see mountains, glaciers, and ice moving. Even despite the thin atmosphere, we see evidence of that atmosphere shaping the surface of that world just as it does on our own planet.”
Pluto’s dunes appear truly Earthly. They’re situated parallel to the edges of the adjacent mountains and perpendicular to the direction of nearby wind streaks. But they’re nothing like the wind-swept, sandy dunes of the Sahara. Pluto’s atmosphere is far too thin to pick up and push tiny grains of methane on its own.
Instead, the particles could be tossed into the air when nitrogen ice sublimes—turns from a solid into a gas, creating an upward jet of nitrogen gas. Once that happens, the planet’s feather-light breeze could push the methane particles, each about the size of a human fat cell, into the ridges observed by Telfer and the New Horizons team.
Discovering the dunes was possible through the combination of an analysis of the famous map of Pluto’s surface produced by New Horizons during its flyby, and the use of another scientist’s modeling. The researchers published their results today in Science.
The structures might not be dunes, of course. “We don’t see sediment move and we don’t see the dunes move,” Alex Hayes, a Cornell University astronomer who was not involved with the study, told Gizmodo. “But that’s the point. The whole paper sees this interesting feature and tries to interpret what they could be… The authors make a convincing argument, but without higher-resolution images, it’s hard to know for sure.”
It’s hard to imagine such a feature made any other way, though, said Telfer. And it wouldn’t be the first extra-terrestrial dune ever spotted, Hayes pointed out. Mars, Saturn’s moon Titan, and even the comet 67P/Churyumov-Gerasimenkoeach have seemingly Earthly wind-swept features.
As to what this might mean for the “is Pluto a planet” debate, the answer is nothing. Pluto is still classified as a dwarf planet, and whether or not we call it a planet is irrelevant to Telfer and his team’s work. After all, There are a host of other interesting and large worlds beyond Pluto. “One thing we’re all looking forward to seeing is New Horizon’s flyby of a Kuiper Belt Object on January 1, next year,” he said. Who knows what mysteries await us on that rock, called Ultima Thule or 2014 MU69.
Monday, May 21, 2018: Two days after the new moon of May, a thin sliver of the waning crescent moon joined the bright planet Venus in the evening sky. Astrophotographer Victor Rogus captured this photo of their conjunction from Arcadia, Florida Thursday (May 17) night as the moon passed about 6 degrees south of Venus. “The pair struggled for my attention through mostly cloudy Florida skies,” Rogus said. “Still, a very beautiful sight in the west as the sky darkened.” — Hanneke Weitering
Stripes of Bedrock in a Martian Crater
Credit: NASA/JPL-Caltech/Univ. of Arizona
Wednesday, May 2, 2018: NASA’s Mars Reconnaissance Orbiter captured this view of eroded bedrock inside an ancient Martian crater using its High Resolution Imaging Science Experiment (HiRISE) camera. These geologic features can reveal clues about the planet’s history, including the presence of water. — Hanneke Weitering
Tuesday, May 1, 2018: Bright stars and colorful nebulas glow in one of the galactic arms of Messier 66, an intermediate spiral galaxy located 36 million light-years away in the constellation Leo. Also known as NGC 3627, this galaxy’s structure is somewhere between a barred and unbarred spiral galaxy. Citizen scientist Kevin Gill processed this image using data from the Hubble Space Telescope. — Hanneke Weitering
Hubble’s Lagoon Nebula in Infrared
An infrared view of the Hubble telescope’s28th anniversary photo reveals a sea of stars that hide behind colorful clouds of gas and dust when viewed in visible-light wavelengths. The Lagoon Nebula is an enormous star-forming region 4,000 light-years away from Earth in the constellation Sagittarius. It can be seen with the naked eye from dark-sky sites and appears about three times larger than the full moon in the night sky. — Hanneke Weitering
Friday, April 20, 2018: NASA’s Juno spacecraft captured this closeup of Jupiter’s Great Red Spot surrounded by turbulent bands of clouds during a close flyby on April 1. This view combines three images taken over the course of 15 minutes. At the time, Juno was between 15,379 miles (24,749 kilometers) and 30,633 miles (49,299 kilometers) above Jupiter’s cloud tops. — Hanneke Weitering
Jupiter’s Swirling Storms
Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill
Monday, April 9, 2018: Elaborate cloud patterns swirl on Jupiter’s northern hemisphere in this new view from NASA’s Juno spacecraft. Juno captured the image on April 1 during its twelfth close flyby of Jupiter, when it was 7,659 miles (12,326 kilometers) from the planet’s cloud tops. Citizen scientist Kevin Gill processed this color-enhanced view using data from the spacecraft’s JunoCam imager. — Hanneke Weitering
Migrating Martian Sands of Lobo Vallis
Credit: NASA/JPL-Caltech/Univ. of Arizona
Friday, April 6, 2018: In this view from NASA’s Mars Reconnaissance Orbiter, bands of bright ripples and dark dunes stretch across the surface of Mars. Over time, winds have pushed these sandy streaks, which are composed of basaltic sand, from the top of the image toward the bottom. This region of the Red Planet is known as Lobo Vallis and was named after a river on the Ivory Coast. — Hanneke Weitering
Thursday, April 5, 2018: The island of Guam bears a striking resemblance to a short-legged llama in this photo by Russian cosmonaut Anton Shkaplerov. He captured the image from 250 miles (400 kilometers) above the Earth at the International Space Station. — Hanneke Weitering
Hangin’ Out in Space
Monday, April 2, 2018: NASA astronaut Drew Feustel dangles from the International Space Station some 250 miles (400 kilometers) above the Earth during a spacewalk on Thursday (March 29). Feustel and his crewmate NASA astronaut Ricky Arnold spent 6 hours and 10 minutes doing maintenance outside of the orbiting lab in what was the 100th spacewalk performed by crewmembers living aboard the space station. — Hanneke Weitering
Friday, March 30, 2018: Squiggly clouds swirl on Saturn’s south polar vortex in this false-color view from NASA’s Cassini spacecraft. A ring of high-altitude clouds circles around a dark region where convective storms are raging in Saturn’s atmosphere. Citizen scientist Kevin Gill created this colorized image using raw data from Cassini. When Cassini captured the image on July 14, 2008, the spacecraft was approximately 243,000 miles (392,000 kilometers) from Saturn. — Hanneke Weitering
Great Pyramids Seen From Space
Thursday, March 29, 2018: Egypt’s famous Giza pyramid complex towers over the Western Desert in this view from the European Space Agency’s Proba-1 minisatellite. The largest of the three pyramids (bottom left) is the Great Pyramid of Giza. To its right is the slightly smaller Pyramid of Khafre, and the smallest of the three is the Pyramid of Menkaure. — Hanneke Weitering
A Cosmic Work of Art
Credit: ESA/PACS/SPIRE/Hi-GAL/UNIMAP/L. Piazzo/La Sapienza/E. Schisano/G. Li Causi/IAPS/INAF
Monday, March 26, 2018: A star-forming region in the Milky Way resembles a Van Gogh painting in this stellar view from the European Space Agency’s Herschel space observatory. The image reveals a web of gas filaments, which astronomers believe are responsible for creating new stars. This region is located 7,500 light-years away in the neighborhood of the Carina Nebula. — Hanneke Weitering
The night sky tonight and on any clear night offers an ever-changing display of fascinating objects you can see, from stars and constellations to bright planets, often the moon, and sometimes special events like meteor showers. Observing the night sky can be done with no special equipment, although a sky map can be very useful, and a good beginner telescope or binoculars will enhance some experiences and bring some otherwise invisible objects into view. You can also use astronomy accessories to make your observing easier, and use our Satellite Tracker page powered by N2YO.com to find out when to see the International Space Station and other satellites. Below, find out what’s up in the night sky tonight (Planets Visible Now, Moon Phases, Observing Highlights This Month) plus other resources (Skywatching Terms, Night Sky Observing Tips and Further Reading).
Monthly skywatching information is provided to Space.com by Chris Vaughan of Starry Night Education, the leader in space science curriculum solutions. Follow Starry Night on Twitter @StarryNightEdu.
Editor’s note: If you have an amazing skywatching photo you’d like to share for a possible story or image gallery, please contact managing editor Tariq Malik email@example.com.
In the southwestern pre-dawn sky of Friday, May 4, the waning gibbous moon will be positioned about 6 degrees to the right of Saturn. A half-day later, skywatchers in parts of Asia will see the moon pass only one degree to the north of the ringed planet. On Saturday morning, the moon’s orbit (green line) will carry it to a position to the left of Saturn. Look for the stars forming the large Teapot asterism of Sagittarius below Saturn all year.
Saturday, May 5 pre-dawn — Eta-Aquariid Meteor Shower Peak
The annual Eta Aquariid Meteor Shower, produced by material from Halley’s Comet, runs from Apr 19 to May 26 and peaks before dawn on Sat., May 6. True Aquariids will travel away from a radiant point in Aquarius, near the eastern horizon. Watch for up to a few dozen meteors per hour, including some fireballs, near the peak. The waning last quarter moon will degrade the sky for this shower.
Sunday, May 6 pre-dawn — Moon Meets Mars
In the pre-dawn sky of Sunday, May 6, the last quarter moon will sit 2 degrees above Mars. Both objects will fit into the field of view of binoculars (orange circle). The binocular field will also include the globular cluster Messier 75, which will be positioned 3 degrees to the left of Mars.
Monday, May 7 at 10:09 p.m. EDT — Last Quarter Moon
At its last quarter phase, the moon rises around midnight and remains visible in the southern sky all morning. At this phase, the moon is illuminated on its western side, towards the pre-dawn sun. Last quarter moons are positioned ahead of the Earth in our trip around the sun. About 3½ hours later, Earth will occupy that same location in space. After this phase, the waning moon traverses the last quarter of its orbit around the earth, on the way to new moon.
Tuesday, May 8 midnight to dawn — Vesta Reverses Direction
On Tuesday, May 8, the major asteroid (4) Vesta will cease its regular eastward orbital motion (red path) and begin a retrograde loop that lasts until late summer. At this time, look for the magnitude 5.5 object sitting 6 degrees to the upper right of Saturn.
Tuesday, May 8 evening — Jupiter at Opposition
On Tuesday, May 8 at 9 p.m. EDT, Jupiter will be exactly opposite the sun in the sky, and visible all night long. The planet’s disk will be the brightest and largest for the year. Around opposition, Jupiter and its four large satellites frequently eclipse and occult one another, and the moons cast round black shadows on the planet, as shown here.
Saturday, May 12 before sunrise — Mercury and Uranus Pairing
Just before sunrise on Saturday, May 12, Mercury and much dimmer Uranus will sit only 3 degrees apart, and very low in the eastern sky. Both objects will fit into the field of view of binoculars (orange circle), with Uranus to the upper left of Mercury.
Monday, May 14 pre-dawn — Mars meets Messier 75
In the pre-dawn sky on the morning of Monday, May 14, Mars’ eastward orbital motion (brown line) will carry it to a position only 18 arc-minutes (or 2/3 of the full moon’s diameter) below the small globular star cluster designated Messier 75. Both objects will appear together in the field of view of a high power telescope (yellow circle).
Monday, May 14 pre-dawn — Saturn passes Messier 22
In the pre-dawn southern sky during the mornings surrounding Monday, May 14, Saturn’s retrograde orbital motion westward will carry it past the bright star cluster designated Messier 22, also known as the Sagittarius Cluster. Closest approach of 1.6 degrees occurs around May 14, when Saturn will be positioned directly above the cluster. Both objects will appear together in the field of view of a low power telescope (orange circle) or binoculars.
Tuesday, May 15 at 7:48 a.m. EDT — New Moon
At its new phase, the moon is travelling between Earth and the sun. Since sunlight is only reaching the far side of the moon, and the moon is in the same region of the sky as the sun, the moon will be completely hidden from view. A day or two after new moon, look for the slender sliver of the young crescent moon to re-appear just above the western horizon after sunset.
Thursday, May 17 evening — Venus and the Young Moon
In the northwestern sky during early evening on Thursday, May 17, the young crescent moon will be situated 6 degrees to the left of Venus. The pair of objects will set together about 10:30 p.m. local time. Look for the open star cluster Messier 35 sitting above and between them in the same binocular field of view (orange circle).
Saturday, May 19 late evening — Moon Approaches the Beehive
Low in the western sky during late evening on Saturday, May 19, the waxing crescent moon will be situated about 6 degrees below the large open star cluster in Cancer known as the Beehive. Other names are Praesepe and Messier 44. Binoculars will show both the moon and the cluster in the same field of view (orange circle). Observers in western North America will see the moon move to within 4 degrees of the cluster before moonset.
Sunday, May 20 evening — Venus meets Messier 35
In the northwestern evening sky of Sunday, May 30, Venus’ orbital motion will carry it within a degree to the right of the bright open star cluster designated Messier 35 in Gemini. Both objects will appear together in the field of view of a low power telescope (orange circle) or binoculars.
Monday, May 21 late evening — Moon Skims Regulus
In late evening on Monday, May 21, the first quarter moon will be situated just above Regulus. At magnitude 1.3, it is the brightest star in Leo. Both objects will fit into the field of view of a small telescope at low power (orange circle). By observing the relative positions of the two objects between dusk and moonset several hours later, the moon’s eastward orbital motion will be made apparent. Minimum separation occurs about 11:15 p.m. EDT.
Monday, May 21 at 11:49 p.m. EDT — First Quarter Moon
After the moon has completed the first quarter of its orbit around Earth, the relative positions of the Earth, sun, and moon cause us to see it half illuminated – on its eastern side. A first quarter moon always rises around noon and sets around midnight, so it is also visible in the afternoon daytime sky. The evenings around first quarter are the best times to see the lunar terrain while it is dramatically lit by low-angled sunlight.
Sunday, May 27 all night — Gibbous Moon near Jupiter
In the southeastern sky on the evening of Sunday, May 27, the nearly full moon and Jupiter will be separated by less than 5 degrees. The two objects will cross the sky together during the night, but the moon’s separation from the bright planet will increase as the moon slides eastwards in its orbit.
Tuesday, May 29 at 10:20 a.m. EDT — Full Milk Moon
The May full moon, known as the Full Milk Moon, Full Flower Moon, or Full Corn Planting Moon, always shines in or near the stars of Libra. Full moons always rise in the east as the sun sets, and set in the west at sunrise. Since no shadows are cast by the vertically impinging sunlight on a full moon, all of the brightness differences are generated by the reflectivity, or albedo, of the surface rocks.
Wednesday, May 30 – Saturn and the Moon meet Messiers (late evening)
In late evening on Wednesday, May 31, the waning gibbous moon will rise in the east with Saturn. The moon will sit only two degrees east of the ringed planet and both objects will fit easily within the field of view of binoculars (orange circle). If you place the naked-eye star Kaus Borealis (Lambda Sagittarii) on the lower right edge of the field, the Messier objects M25, M22, and M28 will be in the same field, at upper left, bottom centre, and lower right respectively.
Mercury will open May among the stars of Pisces – just a few days after its greatest western elongation, and still nearly 27 degrees west of the Sun. For observers in the Northern Hemisphere, the elusive planet will be visible with difficulty in the eastern pre-dawn sky. For most of May, the planet will creep northwards through Aries and into Taurus while hugging the horizon. As it swings towards the sun, the increasing tilt of the morning ecliptic will keep it in view by lifting it higher. During this period of time, Mercury will brighten steadily and shrink in apparent diameter while it waxes from a half-illuminated phase to nearly full. The planet will become lost in the sun’s glare by month’s end. The May apparition will be a very good one for Southern Hemisphere observers.
During May, Venus continues a long and very good apparition that lasts into early autumn. Each evening through the month, our extremely bright sister planet will climb the western early evening sky – moving between the horns of Taurus in mid-month and passing into Gemini on May 19th. On May 1st, Venus will set about 10:45 p.m. local time. On May 31st, it will set after 11:30 p.m. local time. Venus will continually brighten throughout May, reaching magnitude -3.94 at month’s end. Meanwhile, its apparent disk size will increase slightly and its illuminated phase will drop slightly, to 88%. After sunset on May 17, a very young crescent moon will be visible sitting six degrees to the left of the planet. On May 20, Venus will pass only a degree to the north of the bright open cluster designated Messier 35. The pair will fit within the field of view of binoculars.
Mars will spend May in the southeastern pre-dawn sky. Its prograde motion will carry it out of the stars of Sagittarius and into Capricornus on May 15th. During the course of May, Earth’s orbital motion will continue to reduce our distance from the Red Planet. As a result, Mars will double in brightness (from visual magnitude -0.38 to -1.2) and its apparent disk diameter will dramatically increase from 11 to 15 arc-seconds. The last quarter moon will sit 2 degrees above Mars on May 6th. On May 14th, Mars will pass only 18 arc-minutes (or 2/3 of the full moon’s diameter) below the small globular star cluster designated Messier 75. Both objects will appear together in the field of view of a high power telescope.
During May, very bright Jupiter (visual magnitude -2.5) will be an all-night target in central Libra, slowly moving westward in a retrograde loop that will last until July. The planet will reach opposition on May 9th, when it will exhibit a large 43.8 arc-second disk and be located 37 light-minutes from Earth. This will also be a fine time to observe Jupiter’s four Galilean moons. In the southern sky on the evening of May 27th, the nearly full moon and Jupiter will be separated by less than 5 degrees. The two objects will cross the sky together during the night, but the moon’s separation from the bright planet will increase as the moon slides eastwards in its orbit. Jupiter will end May sitting less than a degree north of the bright double star Zubenelgenubi.
Saturn will spend May as a medium bright (magnitude 0.35) yellowish object moving retrograde through the northern part of Sagittarius, on the eastern side of the Milky Way. In early May, the ringed planet will rise in the east shortly after midnight and remain visible until dawn, when it will be 23 degrees above the southern horizon. On May 4th, the waning gibbous moon will be positioned about 6 degrees to the right of Saturn. The following morning, the moon will jump to the planet’s left. On the mornings surrounding May 14th, Saturn will move past the bright star cluster designated Messier 22, also known as the Sagittarius Cluster. Closest approach of 1.6 degrees occurs around May 14th, when Saturn will be positioned directly above the cluster. Both objects will appear together in the field of view of a low power telescope or binoculars.
During May, blue-green Uranus will be in the pre-dawn sky among the stars of southwestern Aries, but it will not be observable until late in the month when it will begin to rise in a dark sky, at about 4 a.m. local time.
Blue-tinted Neptune will spend May in the eastern pre-dawn sky among the stars of Aquarius – sitting about 4 degrees to the east of the naked eye star Hydor. As the month wears on, the planet will rise earlier, increasing the window of time for observing it in telescopes before morning twilight.
Gibbous: Used to describe a planet or moon that is more than 50 percent illuminated.
Asterism: A noteworthy or striking pattern of stars within a larger constellation.
Degrees (measuring the sky): The sky is 360 degrees all the way around, which means roughly 180 degrees from horizon to horizon. It’s easy to measure distances between objects: Your fist on an outstretched arm covers about 10 degrees of sky, while a finger covers about one degree.
Visual Magnitude: This is the astronomer’s scale for measuring the brightness of objects in the sky. The dimmest object visible in the night sky under perfectly dark conditions is about magnitude 6.5. Brighter stars are magnitude 2 or 1. The brightest objects get negative numbers. Venus can be as bright as magnitude minus 4.9. The full moon is minus 12.7 and the sun is minus 26.8.
Terminator: The boundary on the moon between sunlight and shadow.
Zenith: The point in the sky directly overhead.
Night Sky Observing Tips
Adjust to the dark: If you wish to observe faint objects, such as meteors or dim stars, give your eyes at least 15 minutes to adjust to the darkness.
Light Pollution: Even from a big city, one can see the moon, a handful of bright stars and sometimes the brightest planets. But to fully enjoy the heavens — especially a meteor shower, the constellations, or to see the amazing swath across the sky that represents our view toward the center of the Milky Way Galaxy — rural areas are best for night sky viewing. If you’re stuck in a city or suburban area, a building can be used to block ambient light (or moonlight) to help reveal fainter objects. If you’re in the suburbs, simply turning off outdoor lights can help.
Prepare for skywatching: If you plan to be out for more than a few minutes, and it’s not a warm summer evening, dress warmer than you think necessary. An hour of observing a winter meteor shower can chill you to the bone. A blanket or lounge chair will prove much more comfortable than standing or sitting in a chair and craning your neck to see overhead.
Daytime skywatching: When Venus is visible (that is, not in front of or behind the sun) it can often be spotted during the day. But you’ll need to know where to look. A sky map is helpful. When the sun has large sunspots, they can be seen without a telescope. However, it’s unsafe to look at the sun without protective eyewear. See our video on how to safely observe the sun, or our safe sunwatching infographic.
A new photo from a NASA sun-watching spacecraft highlights a huge solar feature that looks a lot like the beloved Big Bird from the children’s television show “Sesame Street.”
The image, snapped today (June 1) by NASA’s Solar Dynamics Observatory(SDO) probe, actually shows a so-called coronal hole — an area where the sun’s corona, or outer atmosphere, is dark. But the resemblance to Big Bird, or one of his feathered kin anyway, is uncanny.
“I can’t get over how much this looks like Big Bird — but it is a coronal hole on the sun,” reads a Twitter post today by Camilla Corona SDO, the spacecraft’s rubber chicken mascot.
The rubber chicken’s Twitter feed is part of NASA’s social media outreach efforts. Officials pasted a picture of the “Sesame Street” character next to the ‘Big Bird’ coronal hole for comparison.
Coronal holes are associated with “open” magnetic field lines, which extend out into interplanetary space rather than arc back to the solar surface. Coronal holes are often found near the sun’s poles, Camilla added, and the high-speed solar wind — a stream of charged particles flowing from the sun’s upper atmosphere — is known to originate in them.
The super-speedy solar wind from the ‘Big Bird’ coronal hole will reach Earth between June 5 and June 7, Camilla said.
After remaining relatively quiet for several years, the sun has entered an active phase of its 11-year solar cycle, firing off a number of strong flares and coronal mass ejections (CMEs) — huge clouds of solar plasma — in the past several months.
CMEs that hit Earth inject large amounts of energy into the planet’s magnetic field, spawning potentially devastating geomagnetic storms that can disrupt GPS signals, radio communications and power grids for days, researchers say. These storms can also super-charge the northern and southern lights, generating brilliant shows for skywatchers at high latitudes.
Experts think the current cycle, known as Solar Cycle 24, will peak in 2013.
The $850 million SDO spacecraft launched in February 2010. The probe’s five-year mission is the cornerstone of a NASA science program called Living with a Star, which aims to help researchers better understand aspects of the sun-Earth system that affect our lives and society.
You can follow SPACE.com senior writer Mike Wall on Twitter: @michaeldwall. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.
The solar system just got a bit stranger. As astronomers continue their ongoing quest to find the elusive Planet Nine, a team found a space rock that lends credence to the idea that a huge super-Earth planet really exists in the outer reaches of our solar system.
The newfound asteroid, called 2015 BP519, adds to a growing body of evidence about little worlds in the solar system being perturbed by something big. Astronomers detailed its discovery and description in a new paper, adding that the bizarre angle of its orbit gives more weight to the idea that a big planet is out there — somewhere — tugging on the asteroid’s path around the sun.
Following up on the discovery, Quanta Magazine recently published an article surveying several astrophysicists who specialize in studying small worlds, including the discoverers of 2015 BP519. While not everybody agreed that Planet Nine was responsible for the strange orbit, the overwhelming majority agreed the new discovery gives more credence to the idea. “The second you put Planet Nine in the simulations, not only can you form objects like this object, but you absolutely do,” lead author Juliette Becker, a graduate student at the University of Michigan, told Quanta. (You can look at the object’s orbit online here.)
It’s not the first time Planet Nine was blamed for pushing an object around. Back in 2014, before Planet Nine was officially hypothesized, astronomers Scott Sheppard and Chadwick Trujillo noticed orbital irregularities in several small bodies beyond Neptune’s orbit. These included dwarf planet Sedna, a newfound object called 2012 VP113, and several other trans-Neptunian objects (TNOs).
Then, in January 2016, astronomers Konstantin Batygin and Mike Brown saw more evidence of TNOs with perturbed orbits. They were the oneswho first gave “Planet Nine” a name, size and distance. They suggested that the mysterious planet could be 10 times more massive than Earth, located 600 astronomical units (AU) from the sun. (One AU is the average distance between the Earth and the sun, which is 93 million miles or 150 million kilometers.)
A flood of studies followed about TNOs and how Planet Nine might have affected their orbits; the following summary is just a sampling. Not all teams were enthusiastic, with one group from the Outer Solar System Origins Survey (OSSOS) cautioning that many of these surveys could be just observational bias.
By October 2017, Batygin said, there were at least five different lines of evidence that suggest the existence of the planet. “If you were to remove this explanation and imagine Planet Nine does not exist, then you generate more problems than you solve. All of a sudden, you have five different puzzles, and you must come up with five different theories to explain them,” he said in a statement.
Giant Waves Nearly Half a Million Miles Across Seen on the Sun for the First Time
By Stephanie Pappas, Live Science Contributor |
Huge, slow-moving waves that drive Earth’s weather and shape the swirls in Jupiter’s atmosphere also exist on the sun, new research reveals.
Called Rossby waves or planetary waves, the large-scale waves occur in all rotating fluids, but now they’ve been identified on the sun. “Solar Rossby waves are gigantic in size, with wavelengths comparable to the solar radius,” study co-author Laurent Gizon, of the Max Planck Institute for Solar System Research, said in a statement. (The average radius of the sunis a whopping 432,450 miles, or 696,000 kilometers.)
Even so, these waves move very slowly, with shallow troughs and peaks, so they aren’t always easy to detect, especially amid the other swirls and disturbances on a body as lively as the sun.
Researchers from the Max Planck Institute for Solar System Research, the University of Göttingen (both in Germany), New York University Abu Dhabi and Stanford University analyzed data from the SDO’s Helioseismic and Magnetic Imager instrument. They focused on bubble-like granules on the visible surface of the sun, called the photosphere. These granules — each about 600 miles (1,000 kilometers) across, according to NASA — are the peak of convection cells, where heated material from the sun’s interior pops up toward the surface, spreads out and then cools, sinking down along the dark lines that divide the granules. According to NASA, these granules are hyperintense, with materials bubbling up as fast as 15,000 mph (more than 24,000 km/h).
One way to think about this is to imagine a two-dimensional ant that lives on the surface of a perfectly spherical balloon. From the ant’s point of view, everywhere on the surface looks the same. There is no center on the sphere’s surface, nor is there an edge.
If you inflate the balloon, the ant will see its two-dimensional universe expand. Draw dots on the surface, and they will move away from one another, just like the galaxies in our real universe do.
For the ant in this two-dimensional universe, any third dimension that extends perpendicular to the balloon’s surface – like traveling into the center of the balloon – has no physical meaning.
“It knows it can go forward and backward. It can go left and right,” said Barbara Ryden, an astrophysicist at The Ohio State University. “But it has no concept of up and down.”
Our universe is a 3D version of the ant’s 2D balloon universe. But the balloon analogy, with its limited surface area, represents a finite universe — which cosmologists still aren’t sure is true of our own, Ryden said. Limited by how far light has traveled since the Big Bang, cosmologists’ observations offer only a finite glimpse of the cosmos, but the entire universe could be infinite.
If that’s the case, then you can replace the balloon with a flat, expanding rubber sheet that extends forever. Or if you want to think of a 3D universe, imagine an infinite loaf of raisin bread that’s continuously expanding. The raisins, in this case, represent the galaxies flying away from one another. “If the universe is infinite,” Ryden told Live Science, “there is no center.”
Whether the universe is flat or curved depends on the total amount of mass and energy in the cosmos. If the mass and energy density of the universe is just right — at the so-called critical density — then the universe would be flat like a sheet, expanding at a steadily accelerating rate.
But if the density is higher, then the cosmos would be curved like the balloon. The extra gravity from this increased density would slow cosmic expansion, eventually bringing that growth to a halt.
Meanwhile, at less than this critical density, cosmic expansion would accelerate even more. In this scenario, the universe would have negative curvature, with a shape somewhat like a saddle. It would still be infinite, however, and thus without a center.
So far, theoretical ideas and observations — such as those of the cosmic microwave background radiation, the afterglow from the Big Bang — point to a remarkably flat universe. But cosmologists still aren’t sure if the universe is indeed flat or if the curvature is so wide that the universe only appears flat — similar to how Earth feels flat on the surface.
That the universe has no center — and, by extension, no edge — is consistent with the cosmological principle, the idea that no place in the universe is special. Observations of how galaxy clusters are distributed and the cosmic microwave background reveal a cosmos that, when you zoom out far enough, does indeed look the same everywhere.
Throughout history, humans have wrongly thought we were at or near the center of the universe —whether that center was the Earth, the sun or even the Milky Way galaxy. But no matter how special we humans think we are, the universe has, so far, shown otherwise.