The Witch Head Nebula, taken on October 24, 2013. Credit and copyright: ftherrmann on Flickr.
Boo! Here’s a great shot of the Witch Head nebula, so named because it resembles the profile of a wicked witch. This nebula’s ‘official’ name is IC 2118, and it is just a cloud of interstellar gas and dust — nothing to be afraid of! The eerie shape is sculpted in part by radiation from the supergiant star Rigel, the brightest star of Orion. In fact, Rigel illuminates the nebula by reflecting off the dust grains, making it glow. Inside the nebula, young stars are being born. This image was taken by a former NASA scientist/engineer Fred Herrmann of the Owl Mountain Observatory near Huntsville, Alabama — ftherrmann2012 on Flickr. You can see an infrared image of this same nebula taken by the WISE spacecraft.
You can see more great images on Universe Today’s Flickr group page (click here to access, or see the new “Photos” tab at the top of our page) and feel free join the group and upload any astronomical images you have taken.
Happy Halloween from all of us here at Universe Today!
The Witch Head nebula is estimated to be hundreds of light-years away in the constellation of Orion. This image was taken by the WISE spacecraft. Credit: NASA.
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The SpaceX Dragon capsule is snared by the International Space Station's Canadarm 2. Credit: NASA
SpaceX — the maker and operator of the Dragon spacecraft that runs periodic cargo flights to the International Space Station — has signed a contract to research, develop and test Raptor methane rocket engines at the NASA Stennis Space Center in southern Mississippi.
The California-based company plans to use the E-2 test stand at Stennis, which is able to support both vertical and horizontal rocket engine tests. (Here are some more technical details from NASA on its capabilities.)
“We have been talking with SpaceX for many years about working at Stennis Space Center, and I am pleased to officially welcome them to our Mississippi family. I hope this is just the beginning of their endeavors in our state,” stated U.S. Senator Thad Cochran (R-Miss) in response to the news. A press release from his office said the presence of the private space company would boost jobs in the region.
The E-2 test stand at NASA Stennis Space Center in southern Mississippi. The stand is used for vertical and horizontal rocket engine tests, among other things. Credit: NASA
There’s little information on SpaceX’s website about what the Raptor engine is or specific development plans, but Space News reports that it would be used for deep-space missions. SpaceX CEO Elon Musk has mentioned the engine previously when talking about Mars missions, according to multiple media reports.
“We are looking to test the whole engine at Stennis, but the first phase starts with the components,” SpaceX spokesperson Emily Shanklin said in the Space News report. “The E-2 stand at Stennis is big enough for components, but we would need a bigger stand for the whole Raptor.”
The two sides are reportedly hashing out a Space Act agreement to establish user fees and other parameters. Once that’s finished, the testing will begin, perhaps as early as next year. SpaceX currently does most of its rocket testing in Texas.
Other parties in the agreement — which was signed by Governor Phil Bryant — include the Mississippi Development Authority, the Harbor Commission and Hancock County Port.
Antarctica's sea ice on Sept. 22, 2013. Scientists say there was more ice on the ocean then than in any time in recorded satellite history. Data came from the Advanced Microwave Scanning Radiometer 2 (AMSR2) sensor on Japan’s Global Change Observation Mission 1st-Water (GCOM-W1) satellite. You can see the land in dark gray and ice shelves in light gray. The yellow line represents the average distribution of sea ice between 1981 and 2000. Credit: NASA/Jesse Allen, using data from the Advanced Microwave Scanning Radiometer 2 (AMSR2) sensor on the Global Change Observation Mission 1st-Water (GCOM-W1) satellite.
Antarctica’s sea ice is creeping further out in the ocean! New data from a Japanese satellite shows that sea ice surrounding the southern continent in late September reached out over 7.51 million square miles (19.47 million square kilometers).
The extent — a slight increase over 2012’s record of 7.50 million square miles (19.44 million square km) — is the largest recorded instance of Antarctica sea ice since satellite records began, NASA said. Data was recorded using the Advanced Microwave Scanning Radiometer 2 (AMSR2) sensor on the Global Change Observation Mission 1st-Water (GCOM-W1) satellite.
“While researchers continue to study the forces driving the growth in sea ice extent, it is well understood that multiple factors—including the geography of Antarctica, the region’s winds, as well as air and ocean temperatures—all affect the ice,” NASA stated.
Update — see below for a more detailed description of why this is an important clue that climate change IS happening.
“Geography and winds are thought to be especially important. Unlike the Arctic, where sea ice is confined in a basin, Antarctica is a continent surrounded by open ocean. Since its sea ice is unconfined, it is particularly sensitive to changes in the winds. As noted by the National Snow and Ice Data Center, some research has suggested that changes in Antarctic sea ice are caused in part by a strengthening of the westerly winds that flow unhindered in a circle above the Southern Ocean.”
For those thinking that increased sea ice means we can relax about climate change, this humorous video explains the difference between land ice (glaciers) and sea ice (which is generated from snow, rainfall and fresh water). It’s definitely worth four minutes of your time. The part about sea ice starts around 2:45.
UPDATE: Just to clarify:
Here’s what the graphic says: “The water around Antarctica is more fresh than it has been in previous years because of increased snow and rainfall as well as in increased contribution of fresh water from melting land ice. This fresh cold water is less dense than the warmer, saltier water below. Previously, that warm salty water would rise, melting the sea ice. But now, bcaus of the lighter fresh water on top, there is less mixing of the ocean’s layer and the surface stays cooler longer. “
And so, there is increased fresh water because of the melting land ice – due to climate change. There is a fundamental difference between sea ice and land ice. Antarctic land ice is the ice which has accumulated over thousands of years on the Antarctica landmass through snowfall. Antarctic sea ice is entirely different as it is ice which forms in salt water during the winter and almost entirely melts again in the summer.
Importantly, when land ice melts and flows into the oceans global sea levels rise on average; when sea ice melts sea levels do not change measurably but other parts of the climate system are affected, like increased absorption of solar energy by the darker oceans.
This illustration compares our Earth with the newly confirmed lava planet Kepler-78b. Kepler-78b is about 20 percent larger than Earth, with a diameter of 9,200 miles, and weighs roughly 1.8 times as much as Earth.
David A. Aguilar (CfA)
A newly verified planet found in data from the Kepler mission delivers on the space telescope’s task of finding Earth-size planets around other stars. The new planet, called Kepler-78b, is the first Earth-sized exoplanet discovered that has a rocky composition like that of Earth. Similarities to Earth, however, end there. Kepler-78b whizzes around its host star every 8.5 hours at a distance of about 1.5 million kilometers, making it a blazing inferno and not suitable for life as we know it.
“We’ve been hearing about the sungrazing Comet ISON that will go very close to the Sun next month,” said Andrew Howard, of the University of Hawaii at Manoa’s Institute for Astronomy. “Comet ISON will approach the Sun about the same distance that Kepler-78b orbits its star, so this planet spends its entire life as a sungrazer.”
Howard is the lead author on one of two papers published in Nature that details the discovery of the new planet. He spoke during a media webcast discussing the finding.
“This is a planet that exists but shouldn’t,” added astronomer David Latham of the Harvard-Smithsonian Center for Astrophysics (CfA), also discussing the discovery during the webcast.
Kepler-78b is 1.2 times the size of Earth with a diameter of 14,800 km (9,200 miles) and 1.7 times more massive. As a result, astronomers say it has a density similar to Earth’s, which suggests an Earth-like composition of iron and rock. A handful of planets the size or mass of Earth have been discovered, but Kepler-78b is the first to have both a measured mass and size. With both quantities known, scientists can calculate a density and determine what the planet is made of.
Its star is slightly smaller and less massive than the sun and is located about 400 light-years from Earth in the constellation Cygnus.
However, the close-in orbit of Kepler-78b poses a challenge to theorists. According to current theories of planet formation, it couldn’t have formed so close to its star, nor could it have moved there. Back when this planetary system was forming, the young star was larger than it is now. As a result, the current orbit of Kepler-78b would have been inside the swollen star.
This diagram illustrates the tight orbit of Kepler-78b, which orbits its star every 8.5 hours at a distance of less than a million miles. It is only 2.7 stellar radii from the center of the star, or 1.7 stellar radii from the star’s surface. David A. Aguilar (CfA)
“It couldn’t have formed in place because you can’t form a planet inside a star,” said team member Dimitar Sasselov, also from CfA. “It couldn’t have formed further out and migrated inward, because it would have migrated all the way into the star. This planet is an enigma.”
One idea, suggested Howard, is that the planet is the remnant core of a former gas giant planet, but that turns out to be a problem as well. “We just don’t know what the origin of this planet is,” Howard said.
However, the two teams of planet hunters feel that its existence bodes well for future discoveries of habitable planets.
The two independent research teams used ground-based telescopes for follow-up observations to confirm and characterize Kepler-78b. The team led by Howard used the W. M. Keck Observatory atop Mauna Kea in Hawaii. The other team led by Francesco Pepe from the University of Geneva, Switzerland, did their ground-based work at the Roque de los Muchachos Observatory on La Palma in the Canary Islands.
To determine the planet’s mass, the teams employed the radial velocity method to measure how much the gravitation tug of an orbiting planet causes its star to wobble. Kepler, on the other hand, determines the size or radius of a planet by the amount of starlight blocked when it passes in front of its host star.
“Determining mass of an Earth-sized planet is technically daunting,” Howard said during the webcast, explaining how they used the HIRES (High Resolution Echelle Spectrometer) on Keck. “We pushed HIRES to its limit. The observations were difficult because the star is young with many more star spots (just like sunspots on our Sun) than our Sun, and we have to remove them from our data. But since this planet orbits every eight and a half hours, we were able to watch an entire orbit in one night. We clearly saw the planet’s signal, and we watched it eight different nights.”
David Aguilar from CfA said both teams knew the other team was studying this star, but they didn’t compare their work until both teams were ready to submit their papers so that they wouldn’t influence each other. “It was very encouraging both teams got the same result,” Aguilar said.
Howard also thought having two separate teams work on the same target was great. “We didn’t have to wait for further confirmation of the planet, because the two teams confirmed each other,” he said. “In science, this is as good as it gets.”
Francesco Pepe from the second team said they benefitted from using a twin of the original HARPS (High Accuracy Radial velocity Planet Searcher) which has found nearly 200 exoplanets. “HARPS North at La Palma has the same precision and efficiency as its twin,” Pepe explained during the webcast, “and we decided to guarantee time to follow up on small exoplanet candidates from Kepler. We optimized our observing strategy and we expect many more confirmations in the coming years from this technique.”
As for Kepler-78b, this is a doomed world. Gravitational tides will continue to pull Kepler-78b even closer to its star. Eventually it will move so close that the star’s gravity will rip the world apart. Theorists predict that the planet will vanish within three billion years. Interestingly, astronomers say, our solar system could have held a planet like Kepler-78b. If it had, the planet would have been destroyed long ago leaving no signs for astronomers today.
“We did not detect additional planets in this system,” said Howard, “but we hope to observe this system more in the future.”
We’ve talked about Venus, the hottest planet in the Solar System, but we know things can get pretty hot here on Earth, too. You may be wondering, where on the surface of the Earth has the highest natural temperature been recorded?
The location of this world record has had some controversy, but as of 2013, the hottest spot on record was the Furnace Creek Ranch in California’s Death Valley. On July 10, 1913, weather instruments measured 56.7 degrees Celsius, or 134 degrees Fahrenheit.
The previous record of 56 degrees at El Azizia, Libya was overturned because a systematic study in 2012 discovered there were errors in the measuring methods.
Similar temperatures to Death Valley’s record have been recorded around the World:
55 degrees in Africa,
53.6 in Asia,
50.7 in Australia,
and 49.1 in Argentina.
But these are just measurements from weather stations. It’s likely there are hotter temperatures, but nobody was around to measure. NASA satellites have spotted regions in Iran’s Lut desert which might have reached 70 degrees Celsius during the summers of 2004 and 2005.
So that’d be the hottest spot on the surface, but what about the hottest natural spot anywhere in the entire planet? Now you’ve got to travel straight down 6,371 kilometers to the very center of the Earth. At the inner core, the temperatures rise to about 5,430 degrees C, or 5700 Kelvin. Amazingly, this is about the same temperature as the surface of the Sun.
Some of this high temperature comes from leftover heat from the formation of the planet, 4.54 billion years ago, but the vast majority comes from the decay of radioactive minerals inside the Earth. It was likely hotter in the past, but all the short-period isotopes have already been depleted.
I keep saying the word “natural”, but what about “unnatural”? Wondering about the hottest temperature EVER generated on Earth? Thermonuclear explosions reach temperatures of tens of millions of Kelvin. Fusion experiments have hit 500 million Kelvin. But that’s nothing.
In 2012, physicists working with the Large Hadron Collider were investigating the conditions that might have existed during the earliest moments of the Big Bang.
They generated a quark gluon plasma that had a temperature of 5.5 trillion Kelvin.
Unless aliens can do better, this is not only the hottest temperature ever recorded on Earth, it’s easily the hottest temperature anywhere in the Universe since the Big Bang itself.
The Hubble Space Telescope image of the inner regions of the lensing cluster Abell 1689 that is 2.2 billion light?years away. Light from distant background galaxies is bent by the concentrated dark matter in the cluster (shown in the blue overlay) to produce the plethora of arcs and arclets that were in turn used to constrain dark energy. Image courtesy of NASA?ESA, Jullo (JPL), Natarajan (Yale), Kneib (LAM)
We keep saying dark matter is so very hard to find. Astronomers say they can see its effects — such as gravitational lensing, or an amazing bendy feat of light that takes place when a massive galaxy brings forward light from other galaxies behind it. But defining what the heck that matter is, is proving elusive. And considering it makes up most of the universe’s matter, it would be great to know what dark matter looks like.
A new experiment — billed as the most sensitive dark matter detector in the world — spent three months searching for evidence of weakly interacting massive particles (WIMPs), which may be the basis of dark matter. So far, nothing, but researchers emphasized they have only just started work.
“Now that we understand the instrument and its backgrounds, we will continue to take data, testing for more and more elusive candidates for dark matter,” stated physicist Dan McKinsey of Yale University, who is one of the collaborators on the Large Underground Xenon (LUX) detector.
A view of the Large Underground Xenon (LUX) dark matter detector. Shown are photomultiplier tubes that can ferret out single photons of light. Signals from these photons told physicists that they had not yet found Weakly Interacting Massive Particles (WIMPs) Credit: Matthew Kapust / South Dakota Science and Technology Authority
LUX operates a mile (1.6 kilometers) beneath the Earth in the state-owned Sanford Underground Research Facility, which is located in South Dakota. The underground location is perfect for this kind of work because there is little interference from cosmic ray particles.
“At the heart of the experiment is a six-foot-tall titanium tank filled with almost a third of a ton of liquid xenon, cooled to minus 150 degrees Fahrenheit. If a WIMP strikes a xenon atom it recoils from other xenon atoms and emits photons (light) and electrons. The electrons are drawn upward by an electrical field and interact with a thin layer of xenon gas at the top of the tank, releasing more photons,” stated the Lawrence Berkeley National Laboratory, which leads operations at Sanford.
“Light detectors in the top and bottom of the tank are each capable of detecting a single photon, so the locations of the two photon signals – one at the collision point, the other at the top of the tank – can be pinpointed to within a few millimeters. The energy of the interaction can be precisely measured from the brightness of the signals.”
The densest regions of the dark matter cosmic web host massive clusters of galaxies. Credit: Van Waerbeke, Heymans, and CFHTLens collaboration.
LUX’s sensitivity for low-mass WIMPs is more than 20 times better than other detectors. That said, the detector was unable to confirm possible hints of WIMPs found in other experiments.
“Three candidate low-mass WIMP events recently reported in ultra-cold silicon detectors would have produced more than 1,600 events in LUX’s much larger detector, or one every 80 minutes in the recent run,” the laboratory added.
Don’t touch that dial yet, however. LUX plans to do more searching in the next two years. Also, the Sanford Lab is proposing an even more sensitive LUX-ZEPLIN experiment that would be 1,000 times more sensitive than LUX. No word yet on when LUX-ZEPLIN will get off the ground, however.
According to a new study, meteors may be less dangerous than we thought, thanks to Earth's atmosphere. Credit: David A Aguilar (CfA).
How did life on Earth originally develop from random organic compounds into living, evolving cells? It may have relied on impacts by enormous meteorites and comets — the same sort of catastrophic events that helped bring an end to the dinosaurs’ reign 65 million years ago. In fact, ancient impact craters might be precisely where life was able to develop on an otherwise hostile primordial Earth.
“This is bigger than finding any dinosaur. This is what we’ve all searched for – the Holy Grail of science,” Chatterjee said.
Our planet wasn’t always the life-friendly “blue marble” that we know and love today. At one point early in its history it was anything but hospitable to life as we know it.
“When the Earth formed some 4.5 billion years ago, it was a sterile planet inhospitable to living organisms,” Chatterjee said. “It was a seething cauldron of erupting volcanoes, raining meteors and hot, noxious gasses. One billion years later, it was a placid, watery planet teeming with microbial life – the ancestors to all living things.”
Exactly how did this transition happen? That’s the Big Question in paleontology, and Chatterjee believes he may have found the answer lying within some of the world’s oldest and largest impact craters.
After studying the environments of the oldest known fossil-containing rocks in Greenland, Australia and South Africa, Chatterjee said these could be remnants of ancient craters and may be the very spots where life began in deep, dark and hot environments — similar to what’s found near thermal vents in today’s oceans.
Larger meteorites that created impact basins of about 350 miles in diameter inadvertently became the perfect crucibles, according to Chatterjee. These meteorites also punched through the Earth’s crust, creating volcanically driven geothermal vents. They also brought the basic building blocks of life that could be concentrated and polymerized in the crater basins.
In addition to new organic compounds — and, in the case of comets, considerable amounts of water — impacting bodies may also have brought the necessary lipids needed to help protect RNA and allow it to develop further.
“RNA molecules are very unstable. In vent environments, they would decompose quickly. Some catalysts, such as simple proteins, were necessary for primitive RNA to replicate and metabolize,” Chatterjee said. “Meteorites brought this fatty lipid material to early Earth.”
How organic compounds in crater basins were encapsulated in lipid membranes and became the first cells (Chatterjee)
Based on research in Australia by University of California professor David Deamer, the ingredients for all-important cell membranes were delivered to Earth via meteorites and existed in water-filled craters.
“This fatty lipid material floated on top of the water surface of crater basins but moved to the bottom by convection currents,” suggests Chatterjee. “At some point in this process during the course of millions of years, this fatty membrane could have encapsulated simple RNA and proteins together like a soap bubble. The RNA and protein molecules begin interacting and communicating. Eventually RNA gave way to DNA – a much more stable compound – and with the development of the genetic code, the first cells divided.”
And the rest, as they say, is history. (Well, biology really, and no small amount of chemistry and paleontology… and some astrophysics… well you get the idea.)
Chatterjee recognizes that further experiments will be needed to help support or refute this hypothesis. He will present his findings Oct. 30 during the 125th Anniversary Annual Meeting of the Geological Society of America in Denver, Colorado.
Image from the new Virgin American safety presentation video. Credit: Virgin Airlines.
No more falling asleep before takeoff during those boring safety presentations – at least on Virgin America Airlines. Delta Airlines previously made their safety presentation a bit more interesting (see below) but Virgin has taken the presentation to new heights, turning the video into a song and dance, literally, with the help of dance stars like Todrick Hall and Madd Chadd.
A false-color image of ocean wind speeds generated by NASA's QuikScat satellite in 1999. Fast wind speeds are shown in orange, and blue ones are slow. The white shows where the wind is blowing. Credit: NASA/JPL-Caltech
Here’s a cool example of a satellite recycling project. NASA used to have a probe called QuikSCAT that took a look at ocean wind speeds — including hurricanes, storms and typhoons. After 10 years of loyal service, the satellite failed in 2009 and a full replacement looked expensive. Now, however, spare parts for QuikSCAT are going to be used on the International Space Station for a low-budget fix (which the agency says will work just fine).
The parts are old — they are from the 1990s — but incredibly, they are functional. NASA also added some newer, commercially available hardware to make ISS-RapidScat fit in the space station as well as the SpaceX Dragon spacecraft that will bring it to orbit in early 2014.
Because this is very much a low-cost project, certain design compromises were made — like not using radiation-hardened computer chips, which is normal in scatterometers of this sort. (This type of device harmlessly sends low-energy microwaves off the Earth’s service to get the information it needs.)
Artist’s conception of how ISS-RadScat will work. Credit: NASA/JPL-Caltech/Johnson Space Center
“If there’s an error or something because of radiation, all we have to do is reset the computer. It’s what we call a managed risk,” stated Howard Eisen, the ISS-RapidScat project manager at NASA’s Jet Propulsion Laboratory.
There’s another big difference with this scatterometer mission: it’s flying in a different orbit that most. A typical mission will do a sun-synchronous orbit, making it cross the Earth’s equator at the same local time every time it orbits the planet (say, 12 p.m. local.) The ISS, however, passes over different parts of Earth at different times.
“This means the instrument will see different parts of the planet at different times of day, making measurements in the same spot within less than an hour before or after another instrument makes its own observations,” NASA stated.
A view of Hurricane Irene taken by the GOES satellite at 2:55 p.m. Eastern Daylight Time on August 24, 2011. Credit: NASA
“These all-hour measurements will allow ISS-RapidScat to pick up the effects of the sun on ocean winds as the day progresses. In addition, the space station’s coverage over the tropics means that ISS-RapidScat will offer extra tracking of storms that may develop into hurricanes or other tropical cyclones.”
NASA plans to share information with the European MetOp ASCAT scatterometer. Between the two missions, NASA expects that about 90% of Earth’s surface will be examined at least once a day,with some parts visible several times a day.
All in all, NASA is presenting the recycling project as a boon at a time when the agency is grappling with its 2014 budget request. Instead of an estimated cost of $400 million to launch a replacement QuikSCAT, the cost of ISS-Rapidscat is expected to reach $26 million.
No fewer than four bright-ish comets greet skywatchers an hour before the start of dawn. From upper left counterclockwise: C/2013 R1 Lovejoy, 2P/Encke, C/2012 X1 and ISON. Credits: Gerald Rhemann, Damian Peach, Gianluca Masi and Gerald Rhemann
Get your astronomical trick-or-treat bags ready. An excursion under the Halloween morning sky will allow you fill it in a hurry — with comets! We’ve known for months that ISON and 2P/Enckewould flick their tails in the October dawn, but no one could predict they’d be joined by Terry Lovejoy’s recent comet discovery, C/2013 R1 (Lovejoy), and the obscure C/2012 X1 (LINEAR). The last surprised all of us when it suddenly brightened by more than 200 times in a matter of days. Almost overnight, a comet found on precious few observing lists became bright enough to see in binoculars. Now comet watchers the world over are losing sleep to get a glimpse of it.
Rarely are four comets this bright in the same quadrant of sky. This map shows the sky facing east about two hours before sunrise on Oct. 31. Take note of the three stars are labeled “Beta”. These are (from top) Beta Cancri, Beta Leonis and Beta Coma Berenices. We’ll use these three stars and the planet Mars to hone in on the comets’ locations in the maps below. Stellarium
Since it’s unusual to have four relatively bright comets in the same chunk of sky at the same time, you don’t want to miss this opportunity. Now that the moon has dwindled to the slightest crescent, this is THE time to hunt for these ghostly apparitions before dawn.
Detailed (updated) map showing Comet Lovejoy’s progress across Cancer in the coming days. It passes very close to the Beehive Cluster on Nov. 6-7. Click for a larger version you can print and use under the stars. All dates are at 6 a.m. CDT; north is up and west to the right and stars are shown to mag. 5. All closeup charts created with Chris Marriott’s SkyMap software
Brightest of the bunch at magnitude 8 and your best bet to see in a standard pair of 50mm binoculars is Comet Lovejoy. Using the maps, look for a round, fuzzy spot with a brighter center not far from the bright star Procyon in Canis Minor. In the coming days, Lovejoy will brighten by an additional 2 to 3 magnitudes as it trucks across Cancer headed toward the Big Dipper. This is one to watch. Lovejoy will likely reach naked eye brightness by mid-November. Small telescope users can see the comet with ease but its developing gas tail is still to faint to spot visually.
Comet Encke drops below Leo and into Virgo over the next two weeks. Your guide star Beta Leo is at upper right. Stars to mag.8. Click to enlarge.
Comet Encke treks around the sun every 3.3 years. Sometimes it’s well placed for viewing and sometimes not. Because of its short period, dedicated comet watchers meet up with it a half dozen or more times during their lives. This apparition is a favorable one with the comet well-positioned in the east at dawn near peak brightness. Current estimates place it magnitude 7.5-8 with only the wispiest of tails. Like Lovejoy, 50mm binoculars under a dark sky should nab it.
A week before Encke reaches its peak magnitude of 6 or 7 at perihelion on Nov. 21, it chases the into the glare of morning twilight. If you want to see this comet, you’ve got about 2 weeks of viewing time left. Make sure to set up in a place with an open view to the east-southeast or you’ll find it hidden by the treeline.
Animation from images taken Oct. 25 and 28 of comet C/2012 X1 (LINEAR) showing its rapidly expanding coma in the wake of an eruptive event in its icy crust. Click image to animate. Credit: Gianluca Masi
Comet C/2012 X1 would have deprived us of a unique sight had it followed the rules. Instead, an eruption of fresh, dust-laden ices from its surface blasted into space to form a gigantic glowing sphere of material that vaulted the comet’s magnitude from a wimpy 13.5 to a vol-luminous 7.5. That’s a difference of 6 magnitudes or a brightness factor of 250 times!
Outbursts of this consequence are rare; the best example of a similar blow-out happened in 2007 when Comet 17P/Holmes cut loose and brightened by half a million times from magnitude 17 to 2.8 in just under two days.
C/2012 X1 (LINEAR) hovers low in the northeast in Coma Berenices near Beta. Because it’s much further from Earth than the other three comets, it moves more slowly across the sky. It has a close conjunction with the brilliant star Arcturus in mid-November. In this map, north is at top left and west to top right. Stars to mag. 8. Click to enlarge.
As with any explosion, the cloud of debris around C/2012 X1 continues to expand. Presently measuring a healthy ~8 arc minutes in diameter (1/4 the size of the full moon), the comet will almost certainly continue to grow and fade with time. Catch it now with binoculars and small telescopes before its veil-like coma thins to invisibility. Like Encke, X1 LINEAR requires an open eastern horizon and best viewed at the start of dawn. Make it the last comet on your observing list after Lovejoy, Encke and ISON.
Mars and several other moderately bright stars in Leo will guide you to Comet ISON in the next week or two. Stars to mag. 10. Click to enlarge.
Ah, ISON. Halloween morning wouldn’t be complete without a visit to this year’s the most anticipated comet.. If it can hold itself together after a searing graze of the sun on November 28, the comet will undoubtedly become a most pleasing sight during the first three weeks of December. Right now it’s a little behind schedule on brightness, but don’t let that worry you – its best days are still ahead.
One of the finest pictures to date of Comet ISON by ace astrophotographer Damian Peach taken on Oct. 27.
Of our four morning treats, Comet ISON is currently the faintest at around magnitude 9.5. Observers with binoculars in the 70-100mm range will see it under dark skies but most of us will need a 6-inch or larger scope at least until mid-November. That’s when ISON’s expected to brighten to magnitude 6, the naked eye limit. Just before it slips into the solar glare, ISON could reach 3rd magnitude around Nov. 21, normally an easy catch with the naked eye, but low altitude will hamper the view.
So open your bag wide tomorrow before dawn and keep it open the next few mornings. Trick or treat!
