Excerpt from mashable.com Thanks to a rare, severe geomagnetic storm, the Northern Lights may be visible on Tuesday night in areas far to the south of its typical home in the Arctic. The northern tier of the U.S., from Washington State to Michiga...
Tag: night (page 3 of 16)
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| Totality! The 2012 total solar eclipse as seen from Australia. Credit and copyright: www.hughca.com. |
Excerpt from universetoday.com
The first of two eclipse seasons for the year is upon us this month, and kicks off with the only total solar eclipse for 2015 on Friday, March 20th.
And what a bizarre eclipse it is. Not only does this eclipse begin just 15 hours prior to the March equinox marking the beginning of astronomical spring in the northern hemisphere, but the shadow of totality also beats path through the high Arctic and ends over the North Pole.
An animation of the March 20th eclipse. Credit: NASA/GSFC/AT Sinclair.
Already, umbraphiles — those who chase eclipses — are converging on the two small tracts of terra firma where the umbra of the Moon makes landfall: the Faroe and Svalbard islands. All of Europe, the northern swath of the African continent, north-central Asia and the Middle East will see a partial solar eclipse, and the eclipse will be deeper percentage-wise the farther north you are .
2015 features four eclipses in all: two total lunars and two solars, with one total solar and one partial solar eclipse. Four is the minimum number of eclipses that can occur in a calendar year, and although North America misses out on the solar eclipse action this time ’round, most of the continent gets a front row seat to the two final total lunar eclipses of the ongoing tetrad on April 4th and September 28th.
How rare is a total solar eclipse on the vernal equinox? Well, the last total solar eclipse on the March equinox occurred back in 1662 on March 20th. There was also a hybrid eclipse — an eclipse which was annular along a portion of the track, and total along another — on March 20th, 1681. But you won’t have to wait that long for the next, as another eclipse falls on the northward equinox on March 20th, 2034.
The path of the March 20th eclipse across Europe, including start times for the partial phases, and the path of totality, click to enlarge. For more maps showing the percentage of occlusion, elevation, and more, click here. Credit: Michael Zeiler/GreatAmercianEclipse.com.
The March 20th eclipse also occurs only a day after lunar perigee, which falls on March 19th at 19:39 UT. This is also one of the closer lunar perigees for 2015 at 357,583 kilometres distant, though the maximum duration of totality for this eclipse is only 2 minutes and 47 seconds just northeast of the Faroe Islands.
Views from selected locales in Europe and Africa. Credit: Stellarium.
This eclipse is number 61 of 71 in solar saros series 120, which runs from 933 to 2754 AD. It’s also the second to last total in the series, with the final total solar eclipse for the saros cycle occurring one saros later on March 30th, 2033.
What would it look like to sit at the North Pole and watch a total solar eclipse on the first day of Spring? It would be a remarkable sight, as the disk of the Sun skims just above the horizon for the first time since the September 2014 equinox. Does this eclipse occur at sunrise or sunset as seen from the pole? It would be a rare spectacle indeed!
An equinoctal eclipse as simulated from the North Pole. Credit: Stellarium.
Practicing eclipse safety in Africa. Credit: Michael Zeiler/GreatAmericanEclipse.com
A solar filtered scope ready to go in Tucson, Arizona. Credit: photo by author.
The view of totality and the planets as seen from the Faroe Islands. Credit: Starry Night.
Solar activity is also another big variable. Witnesses to the October 23rd, 2014 partial solar eclipse over the U.S. southwest will recall that we had a massive and very photogenic sunspot turned Earthward at the time. The Sun has been remarkably calm as of late, though active sunspot region 2297 is developing nicely. It will have rotated to the solar limb come eclipse day, and we should have a good grasp on what solar activity during the eclipse will look like come early next week.
And speaking of which: could an auroral display be in the cards for those brief few minutes of totality? It’s not out of the question, assuming the Sun cooperates. Of course, the pearly white corona of the Sun still gives off a considerable amount of light during totality, equal to about half the brightness of a Full Moon. Still, witnessing two of nature’s grandest spectacles — a total solar eclipse and the aurora borealis — simultaneously would be an unforgettable sight, and to our knowledge, has never been documented!
We also put together some simulations of the eclipse as seen from Earth and space:
Note that an area of southern Spain may witness a transit of the International Space Station during the partial phase of the eclipse. This projection is tentative, as the orbit of the ISS evolves over time. Be sure to check CALSky for accurate predictions in the days leading up to the eclipse.
The ISS transits the Sun during the eclipse around 9:05 UT as seen from southern Spain. Credit: Starry Night.
Excerpt from cbsnews.comALT LAKE CITY -- Police responding to a report from a fisherman about an overturned car in an icy Utah river were stunned to discover an 18-month-old girl dangling in a car seat inside, unconscious but alive. The officers also ...
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| The moon and planet Jupiter will be able to be seen with your naked eyes. And, with some basic binoculars, you’ll be able to see even more. (Photo: UW Space Place) |
Excerpt from wric.com
Just look up! Monday night, you’ll be able to see a beautiful sight. Jupiter and the moon will be the brightest objects in the sky. And, with some basic binoculars, you’ll be able to see even more.
The largest planet in our solar system, Jupiter, will be pairing up with the moon Monday night. The moon makes a pass by Jupiter, and every planet, at some point each month during its orbit. Monday night, the moon will appear fairly large, called a waxing gibbous moon, and that only happens every few years, according to Jim Lattis, Director of UW Space Place at the University of Wisconsin-Madison.
“But the interest need not be in whether it’s unusual. Rather, it’s a beautiful sight and leads people to look up and think about astronomical things and our place among them,” Lattis said.
After Venus sets, Jupiter and the moon will be the two brightest objects in the sky. Jupiter and the moon will reach the high point in our skies in late evening. With binoculars or a telescope, you’ll even be able to see some of Jupiter’s Galilean moons. They’ll look like little points of light.
Excerpt from paranormal.lovetoknow.com By Michelle Radcliff The Bermuda Triangle is an area of mostly open ocean located between Bermuda, Miami, Florida and San Juan, Puerto Rico. The unexplained disappearances of hundreds of ships and air...
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| Venus (right) & Jupiter |
Excerpt from washingtonpost.com
By Blaine Friedlander Jr.
In winter’s waning weeks, Venus and Jupiter continue to accentuate the night heavens, we change our clocks forward and we grab spring with no intention of letting go.
Check the west-southwestern heavens at dusk to spy the vivacious Venus and the dim Mars. In late February, the two planets met for a sweet cosmic waltz, but in March, they appear to separate. Venus approaches negative fourth magnitude (very bright) while Mars makes do at magnitude 1.3 (dim, hard to find in urban light pollution). With a clear sky, Mars looks like a red pinpoint.
A young, waxing crescent moon visits Mars on the evening of March 21, and on the next evening the crescent flirts with Venus.
Robust Jupiter ascends the evening’s eastern sky. Find this gas giant at a -2.5 magnitude, very bright, in the constellation Cancer. The lion in the constellation Leo appears to stare at the planet. By the Ides of March, find it south around 10:30 p.m.
The waxing gibbous moon drops by the dazzling Jupiter on March 2, days before the moon itself becomes full on March 5.
Catch the ringed Saturn rising after midnight in the east-southeast now, hanging out near a gang of constellations, Scorpius, Ophiuchus and Libra. It’s a zero magnitude object, bright enough that it can be seen under urban skies. The waning moon loiters near Saturn before dawn on March 12. On that morning, the reddish star below them is Antares.
We adjust our clocks to Daylight Saving Time at 2 a.m. March 8. Spring forward, moving the clock ahead one hour.
Winter is almost over. Spring is weeks away. The vernal equinox brings spring’s official arrival on March 20 at 6:45 p.m.
Also on March 20 — the day a new moon — the North Atlantic and the Arctic waters get a short total eclipse. We won’t see it here, but Slooh.com will carry it live. Totality will start seconds after 5:44 a.m. and end at 5:47 a.m., according to Geoff Chester of the U.S. Naval Observatory.
Excerpt from csmonitor.com
Researchers at Queen Mary University of London have found the first evidence of false memories in non-human animals.
It has long been known that humans – even those of us who aren't famous news anchors – tend to recall events that did not actually occur. The same is likely true for mice: In 2013, scientists at MIT induced false memories of trauma in mice, and the following year, they used light to manipulate mice brains to turn painful memories into pleasant ones.
Now, researchers at Queen Mary University of London have shown for the first time that insects, too, can create false memories. Using a classic Pavlovian experiment, co-authors Kathryn Hunt and Lars Chittka determined that bumblebees sometimes combine the details of past memories to form new ones. Their findings were published today in Current Biology.
“I suspect the phenomenon may be widespread in the animal kingdom," Dr. Chittka said in a written statement to the Monitor.
First, Chittka and Dr. Hunt trained their buzzing subjects to expect a reward if they visited two artificial flowers – one solid yellow, the other with black-and-white rings. The order didn’t matter, so long as the bee visited both flowers. In later tests, they would present a choice of the original two flower types, plus one new one. The third type was a combination of the first two, featuring yellow-and-white rings. At first, the bees consistently selected the original two flowers, the ones that offered a reward.
But a good night’s sleep seemed to change all that. One to three days after training, the bees became confused and started incorrectly choosing the yellow-and-white flower (up to fifty percent of the time). They seemed to associate that pattern with a reward, despite having never actually seen it before. In other words, the bumblebees combined the memories of two previous stimuli to generate a new, false memory.
“Bees might, on occasion, form merged memories of flower patterns visited in the past,” Chittka said. “Should a bee unexpectedly encounter real flowers that match these false memories, they might experience a kind of deja-vu and visit these flowers expecting a rich reward.”
Bees have a rather limited brain capacity, Chittka says, so it’s probably useful for them to “economize” by storing generalized memories instead of minute details.
“In bees, for example, the ability to learn more than one flower type is certainly useful,” Chittka said, “as is the ability to extract commonalities of multiple flower patterns. But this very ability might come at the cost of bees merging memories from multiple sequential experiences.”
Chittka has studied memory in bumblebees for two decades. Bees can be raised and kept in a lab setting, so they make excellent long-term test subjects.
“They are [also] exceptionally clever animals that can memorize the colors, patterns, and scents of multiple flower species – as well as navigate efficiently over long distances,” Chittka said.
In past studies, it was assumed that animals that failed to perform learned tasks had either forgotten them or hadn’t really learned them in the first place. Chittka’s research seems to show that animal memory mechanisms are much more elaborate – at least when it comes to bumblebees.
“I think we need to move beyond understanding animal memory as either storing or not storing stimuli or episodes,” Chittka said. “The contents of memory are dynamic. It is clear from studies on human memory that they do not just fade over time, but can also change and integrate with other memories to form new information. The same is likely to be the case in many animals.”
Chittka hopes this study will lead to a greater biological understanding of false memories – in animals and humans alike. He says that false memories aren’t really a “bug in the system,” but a side effect of complex brains that strive to learn the big picture and to prepare for new experiences.
“Errors in human memory range from misremembering minor details of events to generating illusory memories of entire episodes,” Chittka said. “These inaccuracies have wide-ranging implications in crime witness accounts and in the courtroom, but I believe that – like the quirks of information processing that occur in well known optical illusions – they really are the byproduct of otherwise adaptive processes.”
“The ability to memorize the overarching principles of a number of different events might help us respond in previously un-encountered situations,” Chittka added. “But these abilities might come at the expense of remembering every detail correctly.”
So, if generating false memories goes hand in hand with having a nervous system, does all this leave Brian Williams off the hook?
“It is possible that he conflated the memories,” Chittka said, “depending on his individual vulnerability to witnessing a traumatic event, plus a possible susceptibility to false memories – there is substantial inter-person variation with respect to this. It is equally possible that he was just ‘showing off’ when reporting the incident, and is now resorting to a simple lie to try to escape embarrassment. That is impossible for me to diagnose.”
But if Mr. Williams genuinely did misremember his would-be brush with death, Chittka says he shouldn’t be vilified.
Excerpt from nbcnews.com
By Katie Linendoll
FOUNTAIN HILLS, Ariz. — If words like UFO, extraterrestrial, crops circles and abductee have ever piqued your paranormal interest, do yourself a favor and head to the International UFO Congress.
The annual conference—which holds the Guinness record for being the largest convention dedicated to unidentified flying objects—takes place in the picturesque desert town of Fountain Hills, and this year it ran from Feb. 18 to 22. It's worth noting that Arizona is known as a hotbed of activity when it comes to sightings. Thousands flock to the annual event, which is produced by Open Minds, a paranormal research organization.
Each attendee has his or her own reason for being there. My goal was to find out if modern science and technology have changed the game when it comes to UFO sightings and evidence gathering.
"A lot of people think, go to a UFO convention, it's going to be tinfoil hats, but that's not what this is. We have NASA astrobiologists speak, scientists, high-ranking military officials, the works. I mean, there's a lot of really credible people covering this subject," said UFO Congress co-organizer and paranormal journalist Maureen Elsberry.
Air Force UFO documents now available online
When attending a UFO conference, the best approach is to come in with an open mind, ask lots of questions and talk with people about why they are there. Everyone has a story, from the speakers to the attendees, and even the vendors (some of whom double as ufologists).
The highlight of this year's conference was undeniably the speaker series, and it was standing room only to see one man, Bob Lazar. Lazar first spoke out in 1989, claiming that he'd worked as a government scientist at a secret mountainside facility south of Area 51's main site, where he saw remarkably advanced UFO technology. Critics have sought to discredit Lazar, questioning his employment record and educational credentials.
During the conference, George Knapp, an investigative TV reporter in Las Vegas who broke the Lazar story in '89, led an onstage question-and-answer session with Lazar, who discussed the work he did at a place called S4. Lazar spoke in detail about the alien UFO hangars and UFO propulsion systems he was allegedly asked to reverse engineer, and even loosely sketched them out for the audience.
"All the science fiction had become reality," said Lazar, who was noticeably uncomfortable and clearly surprised by the fact that, decades later, he remains such a draw.
You never know whom you'll bump into at the Congress. In the vendor hall, I met sculptor Alan Groves, who traveled all the way from Australia to peddle his "true to scale" Zetan alien figurines. I wondered if his side gig was lucrative, only to realize he was selling the figures like hotcakes. Then we talked about his day job, and he told me he's worked on special and creature effects for films such as "Star Wars," "Alien," "Labyrinth" and "Jurassic Park."
Many of the attendees told me that hard evidence is a requirement for ufologists and paranormal field experts. Derrel Sims, also known as Alien Hunter, told me he spent two years in the CIA, and also has served as a police officer and licensed private investigator.
He said his first alien encounter happened at age 4, and others in his family have also seen aliens. In 38-plus years of alien research, Sims has learned this: "If you look, the evidence is there." To date, he said, more than 4,000 pieces of that evidence exist.
Sims is adamant about only working with evidence-based methods, using DNA tests and collecting samples as well as relying on ultraviolet, infrared and x-ray tools in his research. He said that, in 1992, he discovered aliens leave their own kind of fluorescent fingerprint, and he continues to test for these clues. He added that if you have had an alien encounter, it's important to react quickly to gather evidence: "fluorescence" stays on the skin for only 24 hours. He said that other marks aliens leave include "scoop" marks, which are an identifying thread some abductees have in common.
Another commonality he's discovered is heritage. He said that, in his research, he has found 45 percent of all abductions happen to Native Americans, Irish and Celtic people, and he said that women also have a higher chance of being abducted.
When it comes to filming hard-to-explain phenomena, Patty Greer, who makes documentaries about crop circles, said that quadcopters — a.k.a. drones — have added production value to her films. Lynne Kitei, who covered a mass UFO sighting in her book and in the documentary The Phoenix Lights, said that even low-tech tools, like the 35mm film she used, are still a reliable way to gather proof of inexplicable flying craft, especially because they offer something an iPhone doesn't: negatives.
White House responds to UFO request
Night vision also offers added opportunities for UFO researchers, according to Ben Hansen, who was the host and lead investigator of SyFy channel's "Fact or Faked: Paranormal Files." He's now the owner of Night Vision Ops, an online store that sells night-vision technology. Hansen said that the consumer accessibility of new military-grade technologies in thermal and light amplification scopes are upping the game for the everyday UFO enthusiast.
To close out an intense few days on site at the Congress, Hansen's team invited me to a night watch near Arizona's Superstition Mountains. It was fascinating to see the latest optics add incredible clarity to the night sky, amplifying available light up to 50,000 times beyond what the unaided eye can see. Using the right technology, we were also able to see that a certain flying object, which made everyone nearby jump, wasn't a UFO after all. It was a bat.
I was surrounded by some serious tech all weekend, and it was eye-opening to see the ways that UFO hunters are gathering scientific evidence to learn more about the paranormal world. But I have to say, the gadget that was the most useful to me at the conference was my iPhone, which I used to download a free nightlight app for kids. For the few hours I managed to sleep, it was with the soothing illumination provided by "Kiwi the Green Koala." In short, I was officially freaked out.
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| Mercury's extreme temperatures and lack of an atmosphere would make it very difficult, if not impossible, for people to live on the planet. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington |
Excerpt from space.com
By Joseph Castro, Space.com Contributor
Have you ever wondered what it might be like to homestead on Mars or walk on the moons of Saturn? So did we. This is the first in Space.com's 12-part series on what it might be like to live on or near planets in our solar system, and beyond. Check back each week for the next space destination.
With its extreme temperature fluctuations, Mercury is not likely a planet that humans would ever want to colonize. But if we had the technology to survive on the planet closest to the sun, what would it be like to live there?To date, only two spacecraft have visited Mercury. The first, Mariner 10, conducted a series of Mercury flybys in 1974, but the spacecraft only saw the lit half of the planet. NASA's MESSENGER spacecraft, on the other hand, conducted flybys and then entered Mercury's orbit — in March of 2013, images from the spacecraft allowed scientists to completely map the planet for the first time.
MESSENGER photos of Mercury show that the planet has water ice at its poles, which sit in permanent darkness. Mining this ice would be a good way to live off the land, but setting up bases at the poles might not be a good idea, said David Blewett, a participating scientist with the Messenger program.
"The polar regions would give you some respite from the strength of the sun on Mercury," Blewett told Space.com. "But, of course, it's really cold in those permanently shadowed areas where the ice is, and that presents its own challenge."
A better option, he said, would probably be to set up a home base not far from one of the ice caps, perhaps on a crater rim, and have a water mining operation at the pole.
Still, dealing with extreme temperatures on Mercury would likely be unavoidable: Daytime temperatures on the planet can reach 800 degrees Fahrenheit (430 degrees Celsius), while nighttime temperatures can drop down to minus 290 degrees Fahrenheit (minus 180 degrees Celsius).
Scientists once believed Mercury was tidally locked with the sun, meaning that one side of the planet always faces the sun because it takes the same amount of time to rotate around its axis as it does to revolve around the star. But we now know that Mercury's day lasts almost 59 Earth days and its year stretches for about 88 Earth days.
Interestingly, the sun has an odd path through the planet's sky over the course of Mercury's long day, because of the interaction between Mercury's spin rate and its highly elliptical orbit around the sun.
"It [the sun] rises in the east and moves across the sky, and then it pauses and moves backwards just a tad. It then resumes its motion towards the west and sunset," said Blewett, adding that the sun appears 2.5 times larger in Mercury's sky than it does in Earth's sky.
And during the day, Mercury's sky would appear black, not blue, because the planet has virtually no atmosphere to scatter the sun's light. "Here on Earth at sea level, the molecules of air are colliding billions of times per second," Blewett said. "But on Mercury, the atmosphere, or 'exosphere,' is so very rarefied that the atoms essentially never collide with other exosphere atoms." This lack of atmosphere also means that the stars wouldn't twinkle at night.
But Mercury isn't devoid of natural disasters. "The surface is exposed to impacts of all sizes," Blewett said. It also may suffer from earthquakes due to compressive forces that are shrinking the planet (unlike Earth, Mercury doesn't have tectonic activity).
Mercury is about two-fifths the size of Earth, with a similar gravity to Mars, or about 38 percent of Earth's gravity. This means that you could jump three times as high on Mercury, and heavy objects would be easier to pick up, Blewett said. However, everything would still have the same mass and inertia, so you could be knocked over if someone threw a heavy object at you, he added.
Finally, you can forget about a smooth Skype call home: It takes at least 5 minutes for signals from Mercury to reach Earth, and vice versa.
That was more than a regular old shooting star — that was a meteor that illuminated the whole sky.
A giant space rock fired up the firmament Tuesday night near Pittsburgh, and NASA caught the whole thing on camera.
Excerpt from theblaze.com
Using a network of 15 specialized cameras around the country, NASA tracks fireball events throughout the U.S.
NASA estimated the size of Tuesday’s meteor to be roughly 500 pounds and said the rock blew up as it traveled some 45,000 miles per hour through the atmosphere.
For a meteor’s-eye-view of the event, check out NASA’s Facebook post below:
“This celestial visitor had an orbit that took it out to the main asteroid belt between Mars and Jupiter,” read part of NASA’s Facebook post on the meteor. “[I]t came a mightly long way to a fiery end in the predawn Pennsylvania sky.”
The massive rock broke up into tiny fragments in the atmosphere, but NASA said some of those fragments may be near Kittaning, Pennsylvania.
Click to zoom
Excerpt from thespacereporter.com
Astronomers are baffled by images of plumes rising from Mars’ atmosphere in images taken by amateur astronomers in March and April 2012.
The plumes were present for about 10 days though their shapes and sizes changed rapidly during that time, from finger-like tendrils to spherical blobs.
Researchers have proposed several possible explanations for the plumes, which are discussed in an article just published in the journal Nature.
Each of the theories being considered poses problems. One theory, for instaqnce, proposes the plumes are caused by the same magnetic influence that causes the aurora borealis, or Northern Lights, on Earth. The movement of electrically charged particles from the Sun, driven by the solar wind towards Earth’s poles, results in these particles colliding with molecules of gas. These collisions produce the strange lights known as aurorae.
In the study, the researchers admit, “Mars aurorae have been observed near where the plume occurs, a region with a large anomaly in the crustal magnetic field that can drive the precipitation of solar wind particles into the atmosphere.”
They move on to consider another option, namely that the plumes might be clouds high in the Martian atmosphere.
A highly reflective cloud of either water ice, carbon dioxide ice, or dust particles could explain the plumes. But according to computer models, the presence of these clouds “would require exceptional deviations from standard atmospheric circulation models to explain cloud formations at such high altitudes,” explained the paper’s lead author, Agustin Sanchez-Lavega of the Universidad del Pais Vasco in Spain.
The plumes were seen approximately 120 miles (200 km) from Mars’ surface, which is problematic because the highest Martian clouds are seen is 60 miles (100 km) above the planet’s surface. The only way water can condense so far up is if the temperature in that part of Mars’ atmosphere drops 370 degrees Fahrenheit, or 50 degrees Kelvin, below its norm.
Condensation of carbon dioxide would require twice this temperature drop.
A third theory posits the flumes are caused by atmospheric dust. A wind powerful enough to transport dust 111 miles (180 km) above Mars’ surface could occur only around noon, when the Sun’s heat would be strong enough to create such wind currents.
However, the plumes were seen not at noon but in the mornings along the terminator that separates the planet’s day and night sides.
Recently, data from the Hubble Space Telescope was found showing the plumes back in 1997.
Excerpt from space.com Over the next two weeks, you have an excellent chance to spot one of the most rarely observed objects in the sky, the zodiacal light. The zodiacal light takes its name from the ancient band of 12 constellations through which the...
NASA's Dawn space probe has taken the sharpest-yet image of Ceres, a dwarf planet in our solar system's asteroid belt.
Excerpt from SPACE.com
By Mike Wall
Dawn captured the new Ceres images Wednesday (Feb. 4), when the probe was 90,000 miles (145,000 kilometers) from the dwarf planet, the largest object in the main asteroid belt between Mars and Jupiter.
On the night of March 5, Dawn will become the first spacecraft ever to orbit Ceres — and the first to circle two different solar system bodies beyond Earth. (Dawn orbited the protoplanet Vesta, the asteroid belt's second-largest denizen, from July 2011 through September 2012.)
"It's very exciting," Dawn mission director and chief engineer Marc Rayman, who's based at NASA's Jet Propulsion Laboratory in Pasadena, California, said of Dawn's impending arrival at Ceres. "This is a truly unique world, something that we've never seen before."
The 590-mile-wide (950 km) Ceres was discovered by Italian astronomer Giuseppe Piazzi in 1801. It's the only dwarf planet in the asteroid belt, and contains about 30 percent of the belt's total mass. (For what it's worth, Vesta harbors about 8 percent of the asteroid belt's mass.)
Despite Ceres' proximity (relative to other dwarf planets such as Pluto and Eris, anyway), scientists don't know much about the rocky world. But they think it contains a great deal of water, mostly in the form of ice. Indeed, Ceres may be about 30 percent water by mass, Rayman said.
Ceres could even harbor lakes or oceans of liquid water beneath its frigid surface. Furthermore, in early 2014, researchers analyzing data gathered by Europe's Herschel Space Observatory announced that they had spotted a tiny plume of water vapor emanating from Ceres. The detection raised the possibility that internal heat drives cryovolcanism on the dwarf planet, as it does on Saturn's moon's Enceladus. (It's also possible that the "geyser" was caused by a meteorite impact, which exposed subsurface ice that quickly sublimated into space, researchers said).
The interior of Ceres may thus possess liquid water and an energy source — two key criteria required for life as we know it to exist.
Dawn is not equipped to search for signs of life. But the probe — which is carrying a camera, a visible and infrared mapping spectrometer and a gamma ray and neutron spectrometer — will give scientists great up-close looks at Ceres' surface, which in turn could shed light on what's happening down below.
For example, Dawn may see chemical signs of interactions between subsurface water, if it exists, and the surface, Rayman said.
"That's the sort of the thing we would be looking for — surface structures or features that show up in the camera's eye, or something about the composition that's detectable by one of our multiple spectrometers that could show evidence," he told Space.com. "But if the water doesn't make it to the surface, and isn't in large enough reservoirs to show up in the gravity data, then maybe we won't find it."
Dawn will also attempt to spot Ceres' water-vapor plume, if it still exists, by watching for sunlight scattered off water molecules above the dwarf planet. But that's going to be a very tough observation to make, Rayman said.
"The density of the water [observed by Herschel] is less than the density of air even above the International Space Station," he said. "For a spacecraft designed to map solid surfaces of airless bodies, that is an extremely difficult measurement."
Merging onto the freeway
Dawn is powered by low-thrust, highly efficient ion engines, so its arrival at Ceres will not be a nail-biting affair featuring a make-or-break engine burn, as most other probes' orbital insertions are.
Indeed, as of Friday (Feb. 6), Dawn is closing in on Ceres at just 215 mph (346 km/h), Rayman said —and that speed will keep decreasing every day.
"You take a gentle, curving route, and then you slowly and safely merge onto the freeway, traveling at the same speed as your destination," Rayman said. "Ion propulsion follows that longer, more gentle, more graceful route."
Dawn won't start studying Ceres as soon as it arrives. The spacecraft will gradually work its way down to its first science orbit, getting there on April 23. Dawn will then begin its intensive observations of Ceres, from a vantage point just 8,400 miles (13,500 km) above the dwarf planet's surface.
The science work will continue — from a series of increasingly closer-in orbits, including a low-altitude mapping orbit just 230 miles (375 km) from Ceres' surface — through June 30, 2016, when the $466 million Dawn mission is scheduled to end.
Rayman can't wait to see what Dawn discovers.
"After looking through telescopes at Ceres for more than 200 years, I just think it's really going to be exciting to see what this exotic, alien world looks like," he said. "We're finally going to learn about this place."
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