Image from SOHO indicates a chunk of Comet ISON has survived its close pass of the Sun. Credit: NASA/ESA/SOHO.
Update, 8:35 p.m. EST: Uncertainty about Comet ISON’s fate likely will persist for some time. Karl Battams just tweeted that after 2,000 sungrazing comet observations, he has never seen brightening in the same way that ISON (or its remains) appear to be doing right now. We’ll keep watching. Real-time images are available on this website.
Update, 6:30 p.m. EST: An excellent blog post from Phil Plait (who writes the Bad Astronomy blog on Slate) summarizes his take of the comet’s fate; debris (most likely, he says) continues to show up in images. An except: “It held together a long time, got very bright last night, faded this morning, then apparently fell apart. This isn’t surprising; we see comets disintegrate often enough as they round the Sun. ISON’s nucleus was only a couple of kilometers across at best, so it would have suffered under the Sun’s heat more than a bigger comet would have. Still, there’s more observing to do, and of course much data over which to pore.”
Update, 4:40 p.m. EST:On Twitter, the European Space Agency (quoting SOHO scientist Bernhard Fleck) said the comet is gone. Separately, the Naval Research Laboratory’s Karl Battams posted that he thinks recent observations show debris from ISON, but not a nucleus. Astronomers are still monitoring, however.
Update, 3:56 p.m. EST: Something has emerged from perihelion, but the experts are divided as to whether it’s leftovers of ISON’s tail, or the comet itself. Stay tuned.
The fate of Comet C/2012 S1 ISON is uncertain. It made its closest approach to the sun today (Nov. 28) around 1:44 p.m. EST (6:44 p.m. UTC). As of Thursday night, what’s happening to the comet is still unclear, as observers try to keep up hopes for a good comet show in the next few weeks.
It will take a few more hours until NASA and other agencies can say for sure what the comet’s fate is. That said, there still is valuable science that can be performed if ISON has broken up — more details below the jump.
ISON coincided with American Thanksgiving, causing a lot of astronomers and journalists to work holiday hours while pundits made jokes about the comet being “roasted” along with the turkey. Meanwhile, amateur astronomer Stuart Atkinson — author of the Waiting for ISON blog — was among those eagerly awaiting the comet’s closest approach.
But as the comet made its closest approach, astronomers grew more and more skeptical than it had survived. Phil Plait (who writes the Bad Astronomy blog on Slate) pointed out that the comet’s nucleus appeared much dimmer than its tail in images from SOHO (Solar and Heliospheric Observatory), NASA’s sun-gazing spacecraft. This implied that the nucleus was disintegrating.
Plait and Karl Battams — a Naval Research Laboratory astrophysicist who operates the Sungrazing Comets Project — both participated in a NASA Google+ Hangout on ISON. As of about 2 p.m. EST (7 p.m. UTC), both said that they believe ISON is an “ex-comet”, although it will be a few more hours before scientists can say for sure.
The challenge is that the two spacecraft used to watch ISON swing around the sun — the Solar Dynamics Observatory and SOHO — are not necessarily designed to look for comets. Battams and Plait initially said that it sometimes take additional image processing to view information in it. more As time elapsed though, both expressed extreme skepticism that the comet survived.
Even if the comet is dead, Plait pointed out that scientists can still learn a lot from the remaining debris. ISON is believed to be a pristine example of bodies in the Oort Cloud, a vast body of small objects beyond the orbit of Neptune. Examining the dust in its debris trail could tell scientists more about the origins of the solar system.
“The fact that it’s broken up is really cool. There’s a lot we can learn from it and a lot we can get from it,” he said.
Battams added that ISON has been a very unpredictable comet, flaring up when people expected it would fade, and vice versa. “ISON is just weird. It has behaved unpredictably at times. When it’s done something strange, we spent some time scratching our heads, figuring out what is going on and we think we know what it’s doing … it then goes and does something different.”
Amid the waiting came the inevitable social media jokes (including science fiction and fantasy references.)
For others, the comet served as an inspiration for daring to be courageous.
SpaceX Falcon 9 rocket with SES-8 communications satellite awaits launch from Pad 40 at Cape Canaveral, FL, file photo. Credit: Ken Kremer/kenkremer.com
UPDATE: The launch was scrubbed one second before liftoff at 5:39 p.m. EST Thursday. Computers sensed the Falcon 9’s rocket thrust was building up too slowly. No new launch date was immediately set.
CAPE CANAVERAL, FL – All Systems are “GO” for today’s Thanksgiving Day blastoff of the upgraded SpaceX Falcon 9 rocket that could quite literally ‘rock the space industry to its core’ – If all goes well.
Following Monday’s (Nov. 25) scrub during to a series of technical glitches, the rocket, launch pad systems and weather are all cooperating and ready to support the maiden blastoff of the next generation Falcon 9 rocket from Launch Complex 40 at 5:39 p.m. EST.
SpaceX is offering a live webcast of today’s ‘Spacegiving Day’ launch – as they’ve dubbed it.
The live broadcast of the Falcon 9 liftoff from pad 40 on Cape Canaveral Air Force Station, FL begins at 5 p.m. EST and can be viewed here: www.spacex.com/webcast.
The show will feature commentary about the Falcon 9 rocket and launch sequences and the SES-8 commercial satellite from SpaceX corporate headquarters in Hawthorne, CA.
The Falcon 9/SES-8 launch window extends for 65 minutes.
Next Generation SpaceX Falcon 9 rocket with SES-8 communications satellite awaits launch from Pad 40 at Cape Canaveral, FL. Credit: Ken Kremer/kenkremer.com
Today’s (Nov. 28) inaugural launch of the privately developed Falcon 9 rocket with the commercial SES-8 HDTV and telecommunications satellite is especially noteworthy because it also features SpaceX’s first ever launch of any satellite to a Geostationary Transfer Orbit (GTO).
The 3,138 kg (6,918 lbs) SES-8 satellite is a hybrid Ku- and Ka-band spacecraft that will provide TV and communications coverage for the South Asia and Asia Pacific regions.
The Falcon 9 liftoff was postponed to Thanksgiving Day because the FAA did not grant SpaceX a launch permit on Tuesday and Wednesday out of concern it would have significantly impacted allowable flight paths for commercial airliners on two of the busiest travel days of the year, said SpaceX CEO Elon Musk at a media briefing.
SpaceX founder and CEO Elon Musk briefs reporters including Universe Today on Sunday (Nov. 24) in Cocoa Beach, FL prior to planned SpaceX Falcon 9 rocket blastoff with SES-8 communications satellite set for Nov. 28, 2013 from Cape Canaveral, FL. Credit: Ken Kremer/kenkremer.com
The weather forecast currently shows a 90% chance of favorable conditions at liftoff time according to Air Force meteorologists. The only concern is for winds.
The last time a rocket launched on Thanksgiving Day from Cape Canaveral was back in 1959. It involved an Atlas Able rocket with the Pioneer P-3 lunar probe and failed.
Stay tuned here for continuing SpaceX & MAVEN news and Ken’s SpaceX launch reports from on site at Cape Canaveral & the Kennedy Space Center press site.
Learn more about SpaceX, MAVEN, MOM, Mars rovers, Orion and more at Ken’s upcoming presentations
Nov 28: “SpaceX launch, MAVEN Mars Launch and Curiosity Explores Mars, Orion and NASA’s Future”, Kennedy Space Center Quality Inn, Titusville, FL, 8 PM
Dec 11: “Curiosity, MAVEN and the Search for Life on Mars”, “LADEE & Antares ISS Launches from Virginia”, Rittenhouse Astronomical Society, Franklin Institute, Phila, PA, 8 PM
The RESOLVE rover during a 2012 demonstration at the Kennedy Space Center near Orlando, Fla. Credit: NASA/Dmitri Gerondidakis
In 2018, NASA plans to go prospecting at the moon’s south pole with a rover — possibly, a version of the Canadian one in the picture above. The idea is to look for water and similar substances on the lunar surface, with an eye to learn more about living off the land, so to speak.
Launching anything into space is expensive, so if it’s possible to harvest raw materials off a moon or planetary surface, this could make things a bit cheaper. Specifically, NASA is interested in oxygen, water, silicon and light metals such as aluminum and titanium in the moon’s soil or regolith. (This process is called in situ resource utilization capability.)
“The mission, currently planned to launch in early 2018, will demonstrate extraction of oxygen from lunar regolith to validate in situ resource utilization capability,” said NASA spokesperson Trent Perrotto in an e-mail to Universe Today.
“An essential element of this mission is the ability to travel significant distances on the surface to better understand water distribution in the lunar regolith.”
Building a lunar base might be easier if astronauts could harvest local materials for the construction, and life support in general. Credit: NASA/Pat Rawlings
So that’s the background. Where does the rover stand in this? It would carry a payload called RESOLVE (the acronym stands for Regolith & Environment Science, and Oxygen & Lunar Volatile Extraction.) And the rover has already been through some field tests to see how well it performs in environments (fairly) similar to the moon.
In 2009, for example, the Canadian Space Agency did a summer field study with NASA, Perrotto said. “The Canadian rover carried the RESOLVE payload during field tests. The tests helped NASA better understand the requirements of a volatiles-sensing payload, and helped CSA understand tele-operation and rough terrain exploration,” he wrote.
At the time, NASA was working to get the payload ready for flight status in 2011, but the mission design has changed since then. The current design (called Resource Prospector Mission) would have RESOLVE, a Canadian Space Agency rover and drill, and a lander. NASA is now looking for somebody to work on the lander.
The RESOLVE payload and Canadian rover during field testing at the Kennedy Space Center near Orlando, Fla. in 2012. Credit: NASA/Dmitri Gerondidakis
“A request for information was released in July to identify industry interest in a partnership to develop the lander; and an announcement of opportunity is anticipated to be released in early December,” Perrotto wrote.
This mission design is not a guarantee yet. For one thing, NASA is looking at rover alternatives and possibly getting a drill from a United States source instead. It also would depend on funding and agency priorities in the next few years. That said, however, the mission concept is proceeding right now.
In September, Perrotto added, the CSA and NASA did “initial RESOLVE thermal and vacuum testing in September, including a test in [a] regolith-filled vacuum chamber at the NASA Glenn Research Center (GRC) at lunar temperatures and pressures.” RPM passed a mission concept review on Sept. 17 and is in the midst of a preliminary design review that would conclude in fall 2014.
NASA’s Advanced Exploration Systems office has started to look at alternative options to understand “technical constraints by the mission and to assess affordability,” Perrotto added. Meanwhile, the payload team is assessing and looking to reduce risks, while the CSA and NASA are working to “refine technologies for ISRU.”
According to a new proposal, GPS satellites may be the key to finding dark matter. Credit: NASA
Imagine if your spacecraft was punctured and it could do the repair itself, without the need of you going outside on a dangerous spacewalk. Well, a Canadian team has a prototype idea that could lead to self-healing structures in space. The concept is all set, and they’re asking for financial help to launch it on crowdsourcing platform Kickstarter.
Here’s how the Concordia University material would work:
– It’s constructed out of carbon fiber (to reinforce it) and an epoxy resin (for its matrix).
– After the structure is damaged, it would “transport … a healing agent” to that area using microcapsules that are inside various spots on the resin.
– The structure then chemically repairs itself (more technical details here.)
“This self-healing material is of high interest within the aerospace community such as the Canadian Space Agency and the European Space Agency. If viable, it would be capable of increasing the lifetime of space structures,” the team stated on the fundraising page.
“Prolonging the life of a spacecraft will decrease the required maintenance over its lifetime, which is impossible in many cases. For example, the ammonia leak that happened on the International Space Station (ISS) in May was probably caused by a micrometeoroid and orbital debris (MMOD) impact. If a self-healing shield is implemented in the ISS, the advantage would be to reduce the amount of manual repairs needed on the exterior of the craft and generally improve its lifespan in orbit. This would allow for an overall cost reduction for the spacecraft.”
The engineering team (which calls itself Space Concordia) won the first Canadian Satellite Design Challenge and plans to launch the satellite from that challenge, ConSat-1, as part of a European Space Agency program. (The team did not disclose a launch date on Kickstarter, but said the project is “currently in the final stages of completion.”) This self-healing satellite would be called ConSat-2.
Come on, admit it, you’ve had this question. “Since astronomers know that the Universe is expanding, what’s it expanding into? What’s outside of the Universe?” Ask any astronomer and you’ll get an unsatisfying answer. We give you the same unsatisfying answer, but really explain it, so your unsatisfaction doesn’t haunt you any more.
The short answer is that this is a nonsense question, the Universe isn’t expanding into anything, it’s just expanding.
The definition of the Universe is that it contains everything. If something was outside the Universe, it would also be part of the Universe too. Outside of that? Still Universe. Out side of THAT? Also more Universe. It’s Universe all the way down. But I know you’re going to find that answer unsatisfying, so now I’m going to break your brain.
Either the Universe is infinite, going on forever, or its finite, with a limited volume. In either case, the Universe has no edge. When we imagine the Universe expanding after the Big Bang, we imagine an explosion, with a spray of matter coming from a single point. But this analogy isn’t accurate.
A better analogy is the surface of an expanding balloon. Not the 3 dimensional balloon, just its 2 dimensional surface. If you were an ant crawling around the surface of a huge balloon, and the balloon was your whole universe, you would see the balloon as essentially flat under your feet.
Imagine the balloon is inflating. In every direction you look, other ants are moving away from you. The further they are, the faster away they’re moving. Even though it feels like a flat surface, walk in any direction long enough and you’d return to your starting point.
You might imagine a growing circle and wonder what it’s expanding into. But that’s a nonsense question. There’s no direction you could crawl that would get you outside the surface. Your 2-dimensional ant brain can’t comprehend an expanding 3-dimensional object. There may be a center to the balloon, but there’s no center to the surface. Just a shape that extends in all directions and wraps in upon itself. And yet, your journey to make one lap around the balloon takes longer and longer as the balloon gets more inflated.
To better understand how this relates to our Universe, we need to scale things up by one dimension, from a 2-d surface embedded in a 3-d world, to a 3-d volume embedded within a 4-d universe. Astronomers think that if you travel in any direction far enough, you’ll return to your starting position. If you could stare far enough into space, you would be looking at the back of your own head.
The Universe 1.6 billion years after the Big Bang. Image credit: Paul Bode and Yue Shen
And so, as the Universe expands, it would take you longer and longer to lap the Universe and return to your starting position. But there’s no direction you could travel in that would take you outside or “off” of the Universe. Even if you could move faster than the speed of light, you’d just return to your starting position more quickly. We see other galaxies moving away from us in all directions just as our ant would see other ants moving away on the surface of the balloon.
A great analogy comes from my Astronomy Cast co-host, Dr. Pamela Gay. Instead of an explosion, imagine the expanding Universe is like a loaf of raisin bread rising in the oven. From the perspective of any raisin, all the other raisins are moving away in all directions. But unlike a loaf of raisin bread, you could travel in any one direction within the bread and eventually return to your starting raisin.
Remember that our entire comprehension is based on 3-dimensions. If we were 4-dimensional creatures, this would make much more sense. For a much deeper explanation, I highly recommend you watch my good friend, Zogg the Alien explain how the Universe has no edge. After watching his videos, you should totally understand the possible topologies of our Universe.
I hope this helps you understand why there’s no answer to “what is the Universe expanding into?” With no edge, it’s not expanding into anything, it’s just expanding.
NASA's Mars rover Curiosity took this self-portrait, composed of more than 50 images using its robotic arm-mounted MAHLI camera, on Feb. 3, 2013. The image shows Curiosity at the John Klein drill site. A drill hole is visible at bottom left. Credit: NASA / JPL / MSSS / Marco Di Lorenzo / Ken Kremer- kenkremer.com
CAPE CANAVERAL, FL – NASA’s car sized CuriosityMars rover has resumed full science operations and driving following a six day long halt to research activities due to concerns about an electrical power system glitch, which have now been resolved.
On Nov. 17, engineers noticed a fluctuation in voltage on Curiosity that caused the robots handlers to stop science activities and driving towards mysterious Mount Sharp while they searched for the root cause of the electrical issue.
NASA says that the voltage change did not impact the rovers safety or health and the team was acting out of an abundance of caution while investigating the situation from millions of miles away back on Earth.
“The vehicle’s electrical system has a “floating bus” design feature to tolerate a range of voltage differences between the vehicle’s chassis — its mechanical frame — and the 32-volt power lines that deliver electricity throughout the rover. This protects the rover from electrical shorts,” NASA said in a statement.
Curiosity’s voltage level had been about 11 volts since landing day and had declined to about 4 volts on Nov. 17. The electrical issue did not trigger the rover to enter a safe-mode status.
Curiosity scans the Martian landscape to the distant rim of Gale Crater landing site on Sol 463, November 2013. Credit: NASA / JPL / MSSS / Marco Di Lorenzo / Ken Kremer- kenkremer.com
Engineers amassed a list of possible causes for the voltage change while suspending science operations and roving across the Martian crater floor where Curiosity landed nearly a year and a half ago in August 2012.
“We made a list of potential causes, and then determined which we could cross off the list, one by one,” said rover electrical engineer Rob Zimmerman of NASA’s Jet Propulsion Laboratory, Pasadena, Calif.
NASA says that the likely cause is an internal short stemming from the Radioisotope Thermoelectric Generator (RTG) – the rovers nuclear power source.
RTG’s have been commonly used on many NASA missions that also experienced occasional shorts and that had no long term impact or loss of capability on their flights.
“This type of intermittent short has been seen in similar RTGs, including the one on the Cassini spacecraft, which has been orbiting Saturn for years. The rover electronics are designed to operate at variable power supply voltages, so this is not a major problem,” says Curiosity team member Ken Herkenhoff of the USGS in a mission update.
The voltage level had returned its normal level of 11 volts on its own by Nov. 23, when the team had decided to resume science operations.
So it is possible that the same type of intermittent voltage change could recur in the future.
Meanwhile the rover has resumed her epic trek to Mount Sharp and is expected to arrive at the base of the mountain sometime in mid-2014.
Curiosity Spies Mount Sharp – her primary destination. Curiosity will ascend mysterious Mount Sharp and investigate the sedimentary layers searching for clues to the history and habitability o the Red Planet of billions of years. This mosaic was assembled from Mastcam camera images taken on Sol 352 (Aug 2, 2013). Credit: NASA/JPL-Caltech/MSSS/ Marco Di Lorenzo/Ken Kremer
This past weekend, the robot delivered additional portions of powdered rock to the CheMin and SAM labs inside the rover. The sample was collected 6 months ago after drilling into a rock nicknamed “Cumberland” and will supplement prior measurements.
Curiosity has already accomplished her primary science goal of discovering a habitable zone at her landing site.
Scientists expect to broaden the region of Martian habitability once the 1 ton robot begins the ascent of Mount Sharp to investigate the sedimentary layers in the lower reaches of the towering 3 mile (5 km) high mountain, that record Mars geologic and climatic history over a time span of billions of years.
Curiosity looks to the base of Mount Sharp and the Murray buttes – her ultimate climbing destination – in this mosaic assembled from navcam camera images from Sol 465, November 2013. Credit: NASA / JPL / MSSS / Marco Di Lorenzo / Ken Kremer- kenkremer.com
And as both of NASA’s rovers Curiosity and Opportunity ascend Martian mountains, they’ll be joined next September 2014 by a pair of new Martian orbiters from the US and India – MAVEN and MOM – that will significantly expand Earth’s invasion force at the Red Planet.
Stay tuned here for continuing Mars rover, MOM and MAVEN news and Ken’s MAVEN and SpaceXFalcon 9 launch reports from on site at the Kennedy Space Center press center and Cape Canaveral Air Force Station, Florida.
First ever image of Earth Taken by Mars Color Camera aboard India’s Mars Orbiter Mission (MOM) spacecraft while orbiting Earth and before the Trans Mars Insertion firing on Dec. 1, 2013. Image is focused on the Indian subcontinent. Credit: ISRO
CAPE CANAVERAL, FL – MOM is looking at you, kid!
And if the spectacular new image of billions of Earth’s children captured by India’s Mars Orbiter Mission (MOM) is any indication (see above), then we can expect absolutely gorgeous scenes of the Red Planet once the groundbreaking probe arrives there in September 2014.
But despite all that’s been accomplished so far, the space drama is still in its infant stages – because MOM still needs to ignite her thrusters this weekend in order to achieve escape velocity, wave good bye to Earth forever and eventually say hello to Mars!
The picture – snapped from Earth orbit – is focused on the Indian subcontinent, the probes origin.
MOM has captured the imagination of space enthusiasts worldwide.
During testing of the MOM probes payloads – while it’s still flying in a highly elliptical orbit around our Home Planet – engineers from India’s space agency turned the crafts camera homewards to capture the “First ever image of Earth Taken by Mars Color Camera,” according to the Indian Space Research Organization (ISRO).
The beautiful image was taken on Nov. 20 at around 1350 hrs (IST) from a height of almost 70,000 km above earth and has a spatial resolution of 3.5 km, said ISRO.
The image also gives a rather good approximation of what MOM’s color camera will actually see from apoapsis after reaching the Red Planet since the probe will enter a similarly highly elliptical orbit around Mars – ranging in altitude from 366 kilometers (km) x 80,000 kilometers (km).
MOM has just passed by its penultimate perigee. With this, the final orbit of MOM around Earth begins! Credit: ISRO
Following a 10 month interplanetary cruise, MOM is due to arrive in the vicinity of Mars on September 24, 2014 to study the Red Planets’ atmosphere.
At that time, the 440 Newton liquid fueled main engine must fire precisely as planned during the absolutely essential Mars orbital insertion burn to place the probe into orbit about Mars.
But before MOM can accomplish anything at Mars, she must first successfully fire her main engine – to complete the crucial departure from Earth and Trans Mars Insertion (TMI) scheduled for this Saturday!
MOM’s picture perfect Nov. 5 liftoff atop India’s highly reliable four stage Polar Satellite Launch Vehicle (PSLV) C25 from the ISRO’s Satish Dhawan Space Centre SHAR, Sriharikota, precisely injected the spacecraft into an initial elliptical Earth parking orbit of 247 x 23556 kilometers with an inclination of 19.2 degrees.
Since then the engine has fired 6 times to gradually raise the spacecrafts apogee.
The most recent orbit raising maneuver occurred at 01:27 hrs (IST) on Nov 16, 2013 with a burn time of 243.5 seconds increased the apogee from 118,642 km to 192,874 km.
The nail-biting final main engine burn of 1351 seconds is set for this weekend on Dec. 1. It will place MOM on a precise interplanetary trajectory to the Red Planet.
Graphic of MOM approaching its penultimate perigee pass on Nov 26. Credit: ISRO
If all continues to goes well, India will join an elite club of only four who have launched probes that successfully investigated the Red Planet from orbit or the surface – following the Soviet Union, the United States and the European Space Agency (ESA).
The low cost $69 Million MOM mission is the first of two new Mars orbiter science probes from Earth that flawlessly blasted off for the Red Planet this November.
Both MAVEN and MOM’s goal is to study the Martian atmosphere, unlock the mysteries of its current atmosphere and determine how, why and when the atmosphere and liquid water was lost – and how this transformed Mars climate into its cold, desiccated state of today.
The MAVEN and MOM science teams will “work together” to unlock the secrets of Mars atmosphere and climate history, MAVEN’s top scientist Prof. Bruce Jakosky told Universe Today.
Clouds on the ground ! The sky seems inverted for a moment ! Blastoff of India’s Mars Orbiter Mission (MOM) on Nov. 5, 2013 from the Indian Space Research Organization’s (ISRO) Satish Dhawan Space Centre SHAR, Sriharikota. Credit: ISRO
Stay tuned here for continuing MOM and MAVEN news and Ken’s MAVEN and SpaceX Falcon 9 launch reports from on site at the Kennedy Space Center press center and Cape Canaveral Air Force Station, Florida.
Learn more about MOM, MAVEN, Mars rovers, SpaceX, Orion and more at Ken’s upcoming presentations
Nov 28: “SpaceX launch, MAVEN & MOM Mars Launches and Curiosity Explores Mars, Orion and NASA’s Future”, Kennedy Space Center Quality Inn, Titusville, FL, 8 PM
Dec 11: “Curiosity, MAVEN, MOM and the Search for Life on Mars”, “LADEE & Antares ISS Launches from Virginia”, Rittenhouse Astronomical Society, Franklin Institute, Phila, PA, 8 PM
The Large Magellanic Cloud is one of the closest galaxies to our own. Astronomers have now used the power of the ESO’s Very Large Telescope to explore NGC 2035, one of its lesser known regions, in great detail. This new image shows clouds of gas and dust where hot new stars are being born and are sculpting their surroundings into odd shapes. But the image also shows the effects of stellar death — filaments created by a supernova explosion (left). Credit: ESO
Some 160,000 light years away towards the constellation of Dorado (the Swordfish), is an amazing area of starbirth and death. Located in our celestial neighbor, the Large Magellanic Cloud, this huge stellar forge sculpts vast clouds of gas and dust into hot, new stars and carves out ribbons and curls of nebulae. However, in this image taken by ESO’s Very Large Telescope, there’s more. Stellar annihilation also awaits and shows itself as bright fibers left over from a supernova event.
For southern hemisphere observers, one of our nearest galactic neighbors, the Large Magellanic Cloud, is a well-known sight and holds many cosmic wonders. While the image highlights just a very small region, try to grasp the sheer size of what you are looking at. The fiery forge you see is several hundred light years across, and the factory in which it is contained spans 14,000 light years. Enormous? Yes. But compared to the Milky Way, it’s ten times smaller.
Even at such a great distance, the human eye can see many bright regions where new stars are actively forming, such as the Tarantula Nebula. This new image, taken by ESO’s Very Large Telescope at the Paranal Observatory in Chile, explores an area cataloged as NGC 2035 (right), sometimes nicknamed the Dragon’s Head Nebula. But, just what are we looking at?
The Dragon’s Head is an HII region, more commonly referred to as an emission nebula. Here, young stars pour forth energetic radiation and illuminate the surrounding clouds. The radiation tears electrons away from the atoms contained within the gas. These atoms then gel again with other atoms and release light. Swirling in the mix is dark dust, which absorbs the light and creates deep shadows and create contrast in the nebula’s structure.
However, as we look deep into this image, there’s even more… a fiery finale. At the left of the photo you’ll see the results of one of the most violent events in the Universe – a supernova explosion. These troubled tendrils are all that’s left of what once was a star and its name is SNR 0536-67.6. Perhaps when it exploded, it was so bright that it was capable of outshining the Magellanic Cloud… fading away over the weeks or months that followed. However, it left a lasting impression!
ISON: A 2013 pre-perihelion portrait. (Credit and copyright: Efrain Morales/Jaicoa observatory. Used with permission).
“ISON Lives!!!”
“ISON R.I.P…”
Those are just some of the possible headlines that we’ve wrestled with this week, as Comet C/2012 S1 ISON approaches perihelion tomorrow evening. It’s been a rollercoaster ride of a week, and this sungrazing comet promises to keep us guessing right up until the very end.
Comet ISON reaches perihelion on U.S. Thanksgiving Day Thursday, November 28th at around 18:44 Universal Time/ 1:44 PM Eastern Standard Time. ISON will pass 1.2 million kilometres from the surface of the Sun, just over eight times farther than Comet C/2011 W3 Lovejoy did in 2011, and about 38 times closer to the Sun than Mercury reaches at perihelion.
Comet ISON as seen from Ottawa, Canada on the morning of November 20th. (Credit: Andrew Symes/@FailedProtostar).
Earth-based observers essentially lost sight of ISON in the dawn twilight this past weekend, and there were fears that the comet might’ve disintegrated all together as it was tracked by NASA’s STEREO spacecraft. Troubling reports circulated early this week that emission rates for the comet had dropped while dust production had risen, possibly signaling that fragmentation of the nucleus was imminent. Certainly, this comet is full of surprises, and our observational experience with large sungrazing comets of this sort is pretty meager.
ISON (entering frame, to the right) currently “photobombing” SOHO’s LASCO C3 camera. Credit: NASA/ESA/SOHO.
However, as ISON entered the field of view of the Solar and Heliospheric Observatory’s LASCO C3 camera earlier today it still appeared to have some game left in it. NASA’s Solar Dynamics Observatory will pick up ISON starting at around 17:09UT/12:09 PM EST tomorrow, and track it through its history-making perihelion passage for just over two hours until 19:09UT/2:19PM EST.
And just as with Comet Lovejoy a few years ago, all eyes will be glued to the webcast from NASA’s Solar Dynamics Observatory as ISON rounds the bend towards its date with destiny… don’t miss it!
Note: you can also follow ISON’s current progress as seen from SOHO at their website!
The tracking plan for the Solar Dynamics Observatory on November 28th as ISON passes through perihelion. (Credit: NASA/SDO).
For over the past year since its discovery, pundits have pondered what is now the astronomical question of the approaching hour: just what is ISON going to do post-perihelion? Will it dazzle or fizzle? In this context, ISON has truly become “Schrödinger’s Comet,” both alive and dead in the minds of those who would attempt to divine its fate.
Recent estimates place ISON’s nucleus at between 950 and 1,250 metres in diameter. This is well above the 200 metre size that’s considered the “point of no return” for a comet passing this close to the Sun. But again, another key factor to consider is how well put together the nucleus of the comet is: a lumpy rubble pile may not hold up against the intense heat and the gravitational tug of the Sun!
Current updated light curve for ISON. Be sure to check with NASA’s Comet ISON Observing Campaign for the latest updates. (Compiled by Matthew Knight on November 24th, 2013).
But what are the current prospects for spotting ISON after its fiery perihelion passage?
If the comet holds together, reasonable estimates put its maximum brightness near perihelion at between magnitudes -3 and -5, in the range of the planet Venus at maximum brilliancy. ISON will, however, only stand 14’ arc minutes from the disk of the Sun (less than half its apparent diameter) at perihelion, and spying it will be a tough feat that should only be attempted by advanced observers.
Note that for observers based at high northern latitudes “north of the 60,” the shallow angle of the ecliptic might just make it possible to spot Comet ISON low in the dawn after perihelion and before sunrise November 29th:
ISON post-perihelion at sunrise on November 29th as seen from Fairbanks, Alaska. (Created using Starry Night Education software.
We’ve managed to see the planet Venus the day of solar conjunction during similar circumstances with the Sun just below the horizon while observing from North Pole, Alaska.
Most northern hemisphere observers may catch first sight of Comet ISON post-perihelion around the morning of December 1st. Look low to the east, about half an hour before local sunrise. Use binoculars to sweep back and forth on your morning comet dawn patrol. Note that on December 1st, Saturn, Mercury, and the slim waning crescent Moon will also perch nearby!
Comet ISON, Mercury, Saturn and the Moon: looking east on the morning of December 1st as seen from latitude 30 degrees north. (Created using Starry Night Education software).
Comet ISON will rapidly gain elevation on successive mornings as it heads off to the northeast, but will also rapidly decrease in brightness as well. If current projections hold, ISON will dip back below magnitude 0 just a few days after perihelion, and back below naked eye visibility by late December. Observers may also be able to start picking it up low to the west at dusk by mid-December, but mornings will be your best bet.
The path of comet ISON for the first week of December as seen from latitude 30 degrees north. Note: the planets and the Moon are depicted for December 1st. (Created using Stellarium).
Keep in mind, if ISON fizzles, this could become a “death-watch” for the remnants of the comet, as fragments that might only be visible with binoculars or a telescope follow its outward path. If this turns out to be the case, then the best views of the “Comet formerly known as ISON” have already occurred.
Another possible scenario is that the comet might fragment right around perihelion, leaving us with a brief but brilliant “headless comet,” similar to W3 Lovejoy back in late 2011. The forward light scattering angle for any comet is key to visibility, and in this aspect, ISON is just on the grim edge in terms of its potential to enter the annals of “great” comets, such as Comet Ikeya-Seki back in 1965.
ISON will then run nearly parallel to the 16 hour line in right ascension from south to north through the month of December as it crosses the celestial equator, headed for a date with the north celestial pole just past New Years Day, 2014.
Whether as fragments or whole, comets have to obey Sir Isaac and his laws of physics as they trace their elliptical path back out of the solar system. Keep in mind, a comet’s dust tail actually precedes it on its way outbound as the solar wind sweeps past, a counter-intuitive but neat concept we may just get to see in action soon.
Here are some key dates to watch for as ISON makes tracks across the northern hemisphere sky. Passages are noted near stars brighter than +5th magnitude and closer than one degree except as mentioned:
The celestial path of ISON from November 29th to December 15th. (Credit: Starry Night).
December 1st: ISON is grouped with Saturn, Mercury and the slim crescent Moon in the dawn.
December 2nd: Passes near the +4.9 magnitude star Psi Scorpii.
December 3rd: Passes into the constellation Ophiuchus.
December 5th: Passes near the +2.7 magnitude multiple star Yed Prior.
December 6th: Crosses into the constellation Serpens Caput.
December 8th: Crosses from south to north of the celestial equator.
December 15th: Passes into the constellation Hercules and near the +5th magnitude star Kappa Herculis.
December 17th: The Moon reaches Full, marking the middle of a week with decreased visibility for the comet.
December 19th: Passes into the constellation of Corona Borealis.
December 20th: Passes near the +4.8th magnitude star Xi Coronae Borealis.
December 22nd: Passes 5 degrees from the globular cluster M13. Photo op!
The path of Comet ISON from December 16th to January 8th. (Credit: Starry Night).
December 23rd: Crosses back into the constellation Hercules.
December 24th: Passes near the +3.9 magnitude star Tau Herculis.
December 26th: Comet ISON passes closest to Earth at 0.43 A.U. or 64 million kilometres distant, now moving with a maximum apparent motion of nearly 4 degrees a day.
December 26th: Crosses into the constellation Draco and becomes circumpolar for observers based at latitude 40 north.
December 28th: Passes the +2.7 magnitude star Aldhibain.
December 29th: Passes the +4.8 magnitude star 18 Draconis.
December 31st: Passes the 4.9 magnitude star 15 Draconis.
January 2nd: Crosses into the constellation Ursa Minor.
January 4th: Crosses briefly back into the constellation Draco.
January 6th: Crosses back into the constellation Ursa Minor.
January 7th: Crosses into Cepheus; passes within 2.5 degrees of Polaris and the North Celestial Pole.
And after what is (hopefully) a brilliant show, ISON will head back out into the depths of the solar system, perhaps never to return. Whatever the case turns out to be, observations of ISON will have produced some first-rate science… and no planets, popes or prophets will have been harmed in the process. And while those in the business of predicting doom will have moved on to the next apocalypse in 2014, the rest of us will have hopefully witnessed a dazzling spectacle from this icy Oort Cloud visitor, as we await the appearance of the next Great Comet.
Enjoy the show!
ISON: “Great Comet” or “Great Pumpkin?” Photo and gourd-based artwork by author.
Artist's impression of the Milky Way, looking at it edge on. This makes the bulge at the center look like a peanut, astronomers say. Credit: ESO/NASA/JPL-Caltech/M. Kornmesser/R. Hurt.
Remember that 3-D map of the Milky Way that postulated that the center of the galaxy is shaped like a box or peanut? A new math model of the bulge shows that stars in the center of that bulge move in figure-eight orbits (which can also be interpreted as a peanut-shell shape.) Before, previous studies suggested these orbits looked more like bananas.
“The difference is important; astronomers develop theories of star motions to not only understand how the stars in our galaxy are moving today but also how our galaxy formed and evolves,” the Royal Astronomical Society stated.
In the middle of the galaxy, there are a lot of gravitational forces at play due to the sheer number of stars, as well as particles of dust and dark matter, congregating in the area. This makes it harder to model orbits than in more simple situations, such as our own solar system.
This is how a new model envisions it working:
Milky Way. Image credit: NASA
“As the stars go round in their orbits, they also move above or below the plane of the bar. When stars cross the plane they get a little push, like a child on a swing,” the RAS said.
“At the resonance point, which is a point a certain distance from the center of the bar, the timing of the pushes on the stars is such that this effect is strong enough to make the stars at this point move up higher above the plane. (It is like when a child on the swing has been pushed a little every time and eventually is swinging higher.) These stars are pushed out from the edge of the bulge.”
The researchers suppose that the stars would have two “vertical oscillations” in each orbit, but in between the orbits are shaped somewhat like a peanut shell. This “could give rise to the observed shape of the bulge, which is also like a peanut-shell,” RAS stated.
