A portrait of William Shakespeare on the cover of the first Folio of his plays. Credit: Elizabethan Club of Yale University
With all this talk lately of rocks whizzing by Earth (or crashing through the atmosphere), it’s remarkable that we didn’t even know of space rocks a few centuries ago. The first asteroid, 1 Ceres, was discovered in 1801.
Dial back a few centuries, and we were still in the realm of a perfect universe with the Earth at the center. William Shakespeare’s (1564-1616) plays are full of these references. Universe Today recently stumbled across a 1964 Irish Astronomical Journal paper replete with examples.
Shakespeare was born about 20 years after Nicolaus Copernicus, whose book De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres) laid out the case for the Sun-centered solar system. It took a while for Copernicus’ theories to take hold, however.
While bearing in mind that Shakespeare often wrote about historical personages, one passage from Troilus and Cressida demonstrates an example of the characters speaking of the Sun following the other planets in circles around the Earth.
The heavens themselves, the planets, and this centre,
Observe degree, priority and place.
Insisture, course, proportion, season, form,
Office, and custom, in all line of order:
And therefore is the glorious planet Sol
In noble eminence enthroned and sphered
Amidst the other …
An Earth-centered solar system had its problems when predicting the paths of the planets. Astronomers couldn’t figure out why Mars reversed in its path in the sky, for example.
The real explanation is the Earth “catching up” and passing Mars in its orbit, but astronomers in Shakespeare’s time commonly used “epicycles” (small circles in a planet’s orbit) to explain what was going on. Shakespeare wrote about this problem in Henry VI:
Mars his true moving, even as in the heavens,
So in the earth, to this day is not known.
However, the Bard displayed a more modern understanding of the Moon’s movement around the Earth, the paper points out. The Moon’s distance varies in its orbit, a fact spoken about in Othello, although note that Shakespeare attributes madness to the moon’s movements:
It is the very error of the moon;
She comes more near the earth than she was wont
And makes men mad.
For more examples — including what Shakespeare thought about astrology — you can check out the paper here.
What happens when you give 1,000,000 particles their own gravity and spring repulsion and send them out to play? Watch the video above and find out.
This was created by David Moore, a self-taught computer programmer, aspiring physicist and student at San Diego Miramar College. It’s a custom code made with SDL/C++ and 8 days of render time. According to David there’s a bug at the end “where particles can get arbitrarily high energy… but before that it’s very physically accurate!”
It’s fascinating to watch the attraction process take place — one might envision a similar process occurring in the early Universe with the formation of the first galaxies and galactic clusters out of a hot, uniform state. Plus it’s great to see young talented minds like David’s working on such projects for fun!
Canadarm pictured through a winow aboard the ISS will be used to grapple the SpaceX Dragon after planned March 1 liftoff. Credit: NASA/Thomas Mashburn
Wouldn’t you love to wake up to this gorgeous view of our home planet as a big hand waves a friendly good morning ?!
Well, having survived high speed wayward Asteroids and Meteors these past few days, the human crew circling Earth aboard the International Space Station (ISS) is game to snatch a flying Space Dragon before too long.
NASA will dispatch astronaut fun to orbit in the form of the privately built SpaceX Dragon in a tad less than two weeks time that the crew will ensnare with that robotic hand from Canada and join to the ISS.
On March 1 at 10:10 AM EST, a Space Exploration Technologies (SpaceX) Falcon 9 rocket is slated to blast off topped by the Dragon cargo vehicle on what will be only the 2nd commercial resupply mission ever to the ISS.
The flight, dubbed CRS-2, will lift off from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida carrying about 1,200 pounds of vital supplies and science experiments for the six man international crew living aboard the million pound orbiting outpost.
SpaceX Dragon spacecraft stands inside processing hangar at Cape Canaveral Air Force Station in Florida. Teams had just installed the spacecraft’s solar array fairings. Credit: NASA/Kim Shiflett
The ISS would plummet from the sky like a flaming, exploding meteor and disintegrate without periodic and critical cargo and fueling resupply flights from the ISS partner nations.
There will be some heightened anticipation for the March 1 SpaceX launch following the premature shutdown of a 1st stage Merlin engine during the last Falcon 9 launch in 2012.
The solar powered Dragon capsule will rendezvous with the ISS a day later on March 2, when NASA astronauts Kevin Ford and Tom Marshburn will reach out with the Canadian built robotic marvel, grab the Dragon by the proverbial “tail” and attach it to the Earth-facing port of the station’s Harmony module.
The Dragon will remain docked to the ISS for about three weeks while the crew unloads all manner of supplies including food, water, clothing, spare parts and gear and new science experiments.
Then the astronauts will replace all that cargo load with numerous critical experiment samples they have stored during ongoing research activities, as well as no longer needed equipment and trash totaling about 2300 pounds, for the return trip to Earth and a Pacific Ocean splashdown set for March 25 – as things stand now.
SpaceX Falcon 9 rocket before May 2012 blast off from Cape Canaveral Air Force Station, Florida on historic maiden private commercial launch to the ISS. Credit: Ken Kremer/www.kenkremer.com
SpaceX is under contract to NASA to deliver about 44,000 pounds of cargo to the ISS during a dozen flights over the next few years at a cost of about $1.6 Billion.
SpaceX comprises one half of NASA’s Commercial Resupply Services program to replace the cargo up mass capability the US lost following the retirement of NASA’s space shuttle orbiters in 2011.
SpaceX also won a NASA contract to develop a manned version of the Dragon capsule and aims for the first crewed test flight in about 2 to 3 years – sometime during 2015 depending on the funding available from NASA.
The US is now totally dependent on the Russians to loft American astronauts to the ISS on their Soyuz capsules for at least the next 3 to 5 years directly as a result of the shuttle shutdown.
Along with SpaceX, Orbital Sciences Corp also won a $1.9 Billion cargo resupply contract from NASA to deliver some 44,000 pounds of cargo to the ISS using the firm’s new Antares rocket and Cygnus capsule – launching 8 times from a newly constructed pad at NASA’s Wallops Island Facility in Virginia.
The maiden launch of Orbital’s Antares/Cygnus system has repeatedly been delayed – like SpaceX before them.
NASA hopes the first Antares/Cygnus demonstration test flight will now occur in March or April. However, the Antares 1st stage hot fire test scheduled for earlier this week on Feb. 13 had to be aborted at the last second due to a technical glitch caused by a low nitrogen purge pressurization.
For the SpaceX launch, NASA has invited 50 lucky social media users to apply for credentials for the March 1 launch
Watch for my upcoming SpaceX launch reports from the Kennedy Space Center and SpaceX launch facilities.
SpaceX technicians lift a solar array fairing prior to installation on the company’s Dragon spacecraft. The spacecraft will launch on the upcoming SpaceX CRS-2 mission. Credit: NASA/Kim Shiflett
A photo of Asteroid 2012 DA 14 as seen from the suburbs of Paris on February 15, 2013. Credit and copyright: Thierry Legault.
Yesterday a 50 meter (160 foot) rock passed just over 27,000 kilometers (17,000 miles) from the Earth’s surface. This big space rock, named 2012 DA14, dodged us while another smaller and unrelated asteroid gave us an extraterrestrial punch over Russia (read more about that here). Telescopes around the world — both big professional ones and smaller amateur ones — focused on the fast-moving 2012 DA14, whizzing along at 28,100 kilometers per hour (17,450 miles per hour), or 7.82 kilometers per second (4.8 miles per second) relative to Earth.
Here are some of the images from around the world of 2012 DA14. Noted French astrophotographer Thierry Legault sent Universe Today a note that he “easily spotted it visually through the 4″ refractor. It was running very fast amongst the stars!” he said.
In a really nice piece of astrophotography, François Colas from the Pic du Midi observatory in southern France captured the fast moving asteroid with just the right combination of exposure, allowing him to get the asteroid as a point and not a line. He used a Pentax K5 – 6400 ASA – 85mm f/1.4. Field of view 15°
Richard Fleet from Wiltshire, England also got a good capture of the asteroid. “Clouds were a problem most of the evening but I did manage to catch it going past the Coma Berenices cluster,” he said via email. “I saw the asteroid several times in 15×75 binoculars and the motion was obvious in seconds when it was near a star, though it took a bit longer to be sure in the more barren areas.”
He used a used a 200mm lens on a Canon 5D for the very nice sequence as it ‘ran among the stars’:
Image taken remotely from Spain on February 15, 2013 at 22:31UT, 3 hours after the close approach. Credit: Ernesto Guido and Nick Howes/Remanzacco Observatory.
The Remanzacco Observatory team has been following 2012 DA14 for a few days (click on the image above for their animation if it not ‘animating’.) See their website for several different shots from various remote telescopes around the world.
This image shows asteroid 2012 DA14 and the Eta Carinae Nebula, with the white box highlighting the asteroid’s path. The image was taken using a 3″ refractor equipped with a color CCD camera. The telescope is located at the Siding Spring Observatory in Australia and is maintained and owned by iTelescope.net. Credit: Aaron Kingery/NASA/MSFC
Gianluca Masi from the Virtual Telescope Project held a special webcast for the close approach of this asteroid. He reported they had more than 150,000 viewers from 166 countries. “Unfortunately, the clouds came, too, but at least we had some clear skies soon after the minimum distance was [reached],” he wrote. “For the occasion, the PlaneWave 17? robotic unit was used, trusting its exceptional Paramount ME robotic mount. The mount was controlled by TheSkyX Pro suite and the software was perfectly tuned to track this VERY DIFFICULT target. The results shown here speak by themselves: the asteroid was perfectly tracked, despite it was moving at 0.65 degrees per minute! All this after the scope was just slewed, without any manual adjustment! Amazing.”
2012 DA14 was about 36,500 km from Earth at the time.
Animation of 2012 DA14 created from 17 images, each with 3 second of exposures. Credit: Gianluca Masi, Virtual Telescope Project. Click on the image to animate if it is not ‘moving’ in your browser.
The Talmassons astronomy club from Udine, Italy took this imagery:
Shahrin Ahmad from Kuala Lumpur, Malaysia posted some of his images on Google+:
A 30 second exposure of Asteroid 2012 DA14 passing by Theta Crateris on Feb. 15, 2013 at 19:22 UTC, as seen from Malaysia. The Moon is added for comparison.Credit: Shahrin Ahmad
Nahum Mendez Chazarra from Spain’s Centro de Investigación y Divulgación Astronómica del Mediterráneo sent the video below. You can see more images on their Facebook page.
The Bareket Observatory in Israel had a live webcast of 2012 DA14’s close pass, and they reported they had more than 150K viewers overall. Here is a video they put together of some of the highlights of their observations:
Asteroid 2012 DA14 flies by NGC 4244 at a distance of 14 million light years. Credit and copyright: David G. Strange.
Nick Rose from San Mateo, California tracked 2012 DA14 on its way as it headed away from Earth, using a 6″ reflector with a high end Orion CCD imager on a modified Vixen Super Polaris mount, on the evening of February 15. “I inverted the image to make it easier to see the asteroid,” Nick said, “and the video consists of 100 10 second Binned 1×1 images.”
Mikko Suominen, a freelance science journalist from Finland created this 3-D animation based on the JPL’s information graphics using rendering software called Blender. “They ar not extremely precise,” Suominen said via email, “but for popular science purposes I think they are accurate enough.”
Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
Screenshot from a YouTube video claiming to be a crater from the Russian 2013 meteorite
There’s been a lot of really incredible videos and images of the meteor that streaked across Russian skies on Feb. 15, 2013… but this isn’t one of them.
I recently spotted it on YouTube, uploaded by several users and claiming to be a crater from the meteorite. Whether done purposely to deceive or just in error, the fact is that this isn’t from that event. Actually it’s not even a meteorite crater at all.
What this video shows is a feature in Derweze, Turkmenistan. It’s the remains of a 1971 drilling project by Soviet geologists. When the ground under their rig collapsed after breaking into an underground cavern full of natural gas, the geologists decided to set the borehole on fire to flare off the gases.
Panorama of The Door to Hell (Tormod Sandtorv/Wikipedia)
They assumed all the gas would soon burn off and the fire would go out. But it’s still burning today, nearly 42 years later.
The fiery glow from the circular pit has inspired the hole’s local name, “The Door to Hell.” You can find some photos of this infernal feature here.
Anyway, in the nature of not only informing but also preventing the spread of disinformation, hopefully this will help clear up any confusion for those who might run across the same video in coming days. News about the Russian meteor is still — no pun intended — very hot right now, and it’s likely that at least a few fraudulent articles might try to garner some attention.
If you want to see some real videos of the meteor, check out our original breaking news article here and see some photos of an actual resulting crater — icy, not fiery — in a frozen Russian lake here.
In order to not make for more easy hits on the incorrectly-titled video I did not set it to play. If you do still want to watch it, you can find it here.
A meteorite flashes across the sky over Chelyabinsk, Russia, taken from a dashboard camera.
A small asteroid entered Earth’s atmosphere early Friday, February 15, 2013 over Chelyabinsk, Russia at about 9:20 am local Russian time. Initial estimates, according to Bill Cooke, lead for the Meteoroid Environments Office at NASA’s Marshall Space Flight Center, is that the asteroid was about 15 meters (50 feet) in diameter, with a weight of 7,000 metric tons. It hit the atmosphere at a shallow angle of about 20 degrees, at a speed of about 65,000 km/h (40,000 mph).
It traveled through the atmosphere for about 30 seconds before breaking apart and producing violent airburst ‘explosion’ about 20-25 km (12-15 miles) above Earth’s surface, producing an energy shockwave equivalent to a 300 kilotons explosion. That energy propagated down through the atmosphere, stuck the city below – the Chelyabinsk region has a population of about 1 million — and windows were broken, walls collapsed and there were other reports of minor damage throughout the city.
The official impact time was 7:20:26 p.m. PST, or 10:20:26 p.m. EST on Feb. 14 (3:20:26 UTC on Feb. 15).
Cooke said that at this time, the known damage is not due to fragments of the bolide striking the ground but only from the airburst. “There are undoubtedly fragments on the ground, but at the current time no pieces have been recovered that we can verify with any certainty,” Cooke said during a media teleconference today.
He added that the space rock appears to be “an asteroid in nature,” – likely a rocky asteroid since it broke apart in the atmosphere. It wasn’t detected by telescopes searching for asteroids because of its small size, but also because “it came out of the daylight side of our planet – was in the daylight sky and as a result was not detected by any earth based telescopes. #RussianMeteor was not detected from Earth because it came from the daylight side (i.e the Sun-facing side of Earth).
The meteor left a trail in the sky about 480 km (300 miles) long.
Cooke, along with Paul Chodas, a research scientist in the Near Earth Object Program Office at NASA’s Jet Propulsion Laboratory said that asteroids this size hit the Earth on average about once every 100 years. “These are rare events, and it was an incredible coincidence that it happened on the same day as the close flyby of Asteroid 2012 DA14,” Chodas said. “The two are not related in any way.”
The Russian meteor is the largest reported since 1908, when a meteor hit Tunguska, Siberia. Oddly enough, the Tunguska event was caused by an object about the size of 2012 DA14, the asteroid that flew by Earth today harmlessly. The meteor, which was about one-third the diameter of asteroid 2012 DA14, became brighter than the Sun, as seen in some of the videos here. Its trail was visible for about 30 seconds, so it was a grazing impact through the atmosphere.
There were certainly pieces that hit the ground, according to Jon M. Friedrich from Fordham University. “For something that created a bolide and sonic detonation of the size seen in Russia, it seems likely that fragments reached the earth,”Friedrich said in an email to Universe Today. “In fact, there are reports of a crater in a frozen lake and other locations that were in the path of the meteor. The resulting fragments are not likely large – I’d expect some of the absolute largest to be football to basketball sized, with many fragments being smaller, like marbles.”
Chodas said that defending the Earth against tiny asteroids like this is challenging issue, “something that is not currently our goal,” he said. “NASA’s goal it to find the larger asteroids. Even 2012 DA14 is on the smaller size. The tiny asteroid that hit over Russia is very difficult to detect, an in order to defend the Earth, the problem and issue there is to find these things early enough to do something about it if we wanted to divert it. While smaller asteroids are easier to divert, they are much more difficult to detect.”
“What an amazing day for near Earth objects,” Chodas said, “with two events happening on the same day.”
The lead animation courtesy of Analytical Graphics, Inc.
We interrupt your regular Weekly Space Hangout with this extra special edition to cover to the two asteroid-related events: the Russian meteor explosion and the close pass of Asteroid 2012 DA14.
We record the Weekly Space Hangout every Friday at 12 pm Pacific / 3 pm Eastern. You can watch us live on Google+, Cosmoquest or listen after as part of the Astronomy Cast podcast feed (audio only).
The January 2013 occultation of Jupiter by the Moon as seen from South America. (Image courtesy of Luis Argerich & Nightscape Photography; used with permission.
The movement of the Moon makes a fascinating study of celestial mechanics. Despite the light pollution it brings to the nighttime sky, we’re fortunate as a species to have a large solitary satellite to give us lessons in “Celestial Mechanics 101″
This weekend, we’ll get to follow that motion as the Moon crosses into the constellation Taurus for a near-pass of the planet Jupiter, and for a very few citizens of our fair world, occults it.
The Moon versus Jupiter during the previous occultation of the planet last month. (Image courtesy of Luis Argerich at Nightscape Photography; used with permission).
In astronomy, the term “occultation” simply means that one astronomical body passes in front of another. The term has its hoary roots in astronomy’s ancient past; just like the modern day science of chemistry sprung from the pseudo-science of alchemy, astronomy was once intertwined with the arcane practice of astrology, although the two have long since parted ways. When I use the term “occultation” around my non-space geek friends, (I do have a few!) I never fail to get a funny look, as if I just confirmed every wacky suspicion that they ever had about us backyard astronomers…
But those of us who follow lunar occultations never miss a chance to observe one. You’ll actually get to see the motion of the Moon as it moves against the background planet or star, covering it up abruptly. The Moon actually moves about 12° degrees across the sky per 24 hour period.
The position of the Moon & Jupiter as seen from Tampa (Feb 18th, 7PM EST), Perth, (Feb 18th 11:30UT) & London (Feb 18th at 19UT). Created by the author using Stellarium.
On the evening of Monday, February 18th, the 56% illuminated waxing gibbous Moon will occult Jupiter for Tasmania and southern Australia around 12:00 Universal Time (UT). Folks along the same longitude as Australia (i.e., eastern Asia) will see a close pass of the pair. For North America, we’ll see the Moon approach Jupiter and Aldebaran of February 17th (the night of the Virtual Star Party) and the Moon appear past the pair after dusk on the 18th.
Orientation of Jupiter, the Moon & Vesta on the evening of February 18th for North America. (Created by the author in Starry Night).
But fret not; you may still be able to spot Jupiter near the Moon on the 18th… in the daytime. Daytime planet-spotting is a fun feat of visual athletics, and the daytime Moon always serves as a fine guide. Jupiter is juuuuuust bright enough to see near the Moon with the unaided eye if you know exactly where to look;
Jupiter captured during a close 2012 pass in the daytime! (Photo by author).
To see a planet in the daytime, you’ll need a clear, blue sky. One trick we’ve used is to take an empty paper towel tube and employ it as a “1x finder” to help find our target… binoculars may also help! To date, we’ve seen Venus, Jupiter, Sirius & Mars near favorable opposition all in the daylight… Mercury and Vega should also be possible under rare and favorable conditions.
This week’s occultation of Jupiter is the 3rd and final in a series that started in December of last year. The Moon won’t occult a planet again until an occultation of Venus on September 8th later this year, and won’t occult Jupiter again until July 9th, 2016. We’re also in the midst of a long series of occultations of the bright star Spica (Alpha Virginis) in 2013, as the Moon occults it once every lunation from somewhere in the world. Four major stars brighter than +1st magnitude lie along the Moon’s path near the ecliptic; Spica, Aldebaran, Regulus, and Antares which we caught an occultation of in 2009;
Also of note: we’re approaching a “plane-crossing” of the Jovian moons next year. This means that we’ll start seeing Callisto casting shadows on the Jovian cloud tops this summer on July 20th, and it will continue until July 21st, 2016. The orbits of the Jovian moons appear edge-on to us about every five years, and never really deviate a large amount. Callisto is the only moon that can “miss” casting a shadow on the disk of Jupiter in its passage. The actual plane crossing as seen from the Earth occurs in November 2014. Jupiter reaches solar conjunction this year on June 19th and doesn’t come back into opposition until early next year on January 5th. 2013 is an “opposition-less” year for Jupiter, which occurs on average once per every 11-12 years. (One Jovian orbit equals 11.8 Earth years).
The Moon plus Jupiter during last month’s close conjunction. (Photo by author).
But wait, there’s more… the Moon will also occult +7.7th magnitude 4 Vesta on February 18th at~21:00 UT. This occultation occurs across South America and the southern Atlantic Ocean. It would be fun to catch its ingress behind the dark limb of the Moon, and we bet that a precisely timed video might just show evidence for Vesta’s tiny angular diameter as it winks out. For North American observers, Vesta will sit just off the northern limb of the Moon… if you have never seen it, now is a great time to try!
Finally, we realized that also in the field with 4 Vesta is an explorer that just departed its environs, NASA’s Dawn spacecraft. Although unobservable from Earth, we thought that it would be an interesting exercise to see if it gets occulted by the Moon as well this week, and in fact it does, for a very tiny slice of the planet;
The occultation of the Dawn spacecraft as seen from Earth. Created by the author using Occult 4.0.
Hey, calculating astronomical oddities is what we do for fun… be sure to post those pics of Jupiter, the Moon and more up to our Universe Today Flickr page & enjoy the celestial show worldwide!
DE-STAR, a proposal to blow up asteroids as they bear down on Earth. Credit: Philip M. Lubin
The uncanny — but unrelated — combination of today’s close flyby of Asteroid 2012 DA14 and the meteor that created an airburst event over Russia has many wondering how we could deal with future potential threats to Earth from space. A group of researchers are hoping to aim a laser-blasting vaporizer in its direction and blow it away.
Dubbed DE-STAR, or Directed Energy Solar Targeting of Asteroids and exploRation, the theoretical orbital system is designed to convert the sun’s energy into laser blasts that would annihilate any cosmic intruders bearing down on Earth.
Although the system sounds like a plot from a science fiction movie, the researchers — led by scientists at two California universities — maintain that it is built on sound principles.
“This system is not some far-out idea from Star Trek,” stated Gary Hughes, a researcher and professor from California Polytechnic State University, San Luis Obispo, in a press release.
“All the components of this system pretty much exist today. Maybe not quite at the scale that we’d need – scaling up would be the challenge – but the basic elements are all there and ready to go. We just need to put them into a larger system to be effective, and once the system is there, it can do so many things.”
Construction details were not clear in a press release advertising DE-STAR, but the researchers describe astonishing results from even a modest-sized version of the system.
DE-STAR was modeled at several different sizes. At 328 feet (100 meters) in diameter, which is double the International Space Station’s size, it could “start nudging comets or asteroids out of their orbits,” Hughes stated.
A 6.2 mile (10-kilometer) DE-STAR version could send 1.4 megatons of energy daily to the marauding asteroid, providing enough juice every year to kill a space rock as big as 1,640 feet (500 meters) across. (That’s more than 10 times the size of 2012 DA14, which came within 17,200 miles of Earth Feb. 15.)
“Our proposal assumes a combination of baseline technology –– where we are today –– and where we almost certainly will be in the future, without asking for any miracles,” added Philip Lubin, who is with the University of California, Santa Barbara.
Besides asteroid annihilation, DE-STAR could give a fuel boost to long-distance space travellers.
A proposed DE-STAR 6 (size not disclosed) is advertised as able to push “a 10-ton spacecraft at near the speed of light, allowing interstellar exploration to become a reality without waiting for science fiction technology such as ‘warp drive’ to come along.”
The press release did not reveal a budget for any version of the DE-STAR, how it would be constructed, or how quickly the system could begin fencing with asteroids.
Researchers emphasized, however, that system proposals such as theirs must be taken seriously to ward off incoming space rocks.
“We have to come to grips with discussing these issues in a logical and rational way,” stated Lubin.
“We need to be proactive rather than reactive in dealing with threats. Duck and cover is not an option. We can actually do something about it and it’s credible to do something. So let’s begin along this path. Let’s start small and work our way up. There is no need to break the bank to start.”
In a wave of media releases, the latest studies performed by NASA’s Fermi Gamma-ray Space Telescope are lighting up the world of particle astrophysics with the news of how supernovae could be the progenitor of cosmic rays. These subatomic particles are mainly protons, cruising along through space at nearly the speed of light. The rest are electrons and atomic nuclei. When they meet up with a magnetic field, their paths change like a bumper car in an amusement park – but there’s nothing amusing about not knowing their origins. Now, four years of hard work done by scientists at the Kavli Institute for Particle Astrophysics and Cosmology at the Department of Energy’s (DOE) SLAC National Accelerator Laboratory has paid off. There is evidence of how cosmic rays are born.
“The energies of these protons are far beyond what the most powerful particle colliders on Earth can produce,” said Stefan Funk, astrophysicist with the Kavli Institute and Stanford University, who led the analysis. “In the last century we’ve learned a lot about cosmic rays as they arrive here. We’ve even had strong suspicions about the source of their acceleration, but we haven’t had unambiguous evidence to back them up until recently.”
Until now, scientists weren’t clear on some particulars – such as what atomic particles could be responsible for the emissions from interstellar gas. To aid their research, they took a very close look at a pair of gamma ray emitting supernova remnants – known as IC 443 and W44. Why the discrepancy? In this case gamma rays share similar energies with cosmic ray protons and electrons. To set them apart, researchers have uncovered the neutral pion, the product of cosmic ray protons impacting normal protons. When this happens, the pion rapidly decays into a set of gamma rays, leaving a signature decline – one which provides proof in the form of protons. Created in a process known as Fermi Acceleration, the protons remain captive in the rapidly moving shock front of the supernova and aren’t affected by magnetic fields. Thanks to this property, the astronomers were able to trace them back directly to their source.
“The discovery is the smoking gun that these two supernova remnants are producing accelerated protons,” said lead researcher Stefan Funk, an astrophysicist with the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University in California. “Now we can work to better understand how they manage this feat and determine if the process is common to all remnants where we see gamma-ray emission.”
Are they little speedsters? You betcha. Every time the particle passes across the shock front, it gains about 1% more speed – eventually enough to break free as cosmic ray. “Astronauts have documented that they actually see flashes of light associated with cosmic rays,” Funk noted. “It’s one of the reasons I admire their bravery – the environment out there is really quite tough.” The next step in this research, Funk added, is to understand the exact details of the acceleration mechanism and also the maximum energies to which supernova remnants can accelerate protons.
However, the studies don’t end there. More new evidence of supernovae remnants acting like particle accelerators emerged during careful observational analysis by the Serbian astronomer Sladjana Nikolic (Max Planck Institute for Astronomy). They took a look at the composition of the light. Nikolic explains: “This is the first time we were able to take a detailed look at the microphysics in and around the shock region. We found evidence for a precursor region directly in front of the shock, which is thought to be a prerequisite of cosmic ray production. Also, the precursor region is being heated in just the way one would expect if there were protons carrying away energy from the region directly behind the shock.”
Nikolic and her colleagues employed the spectrograph VIMOS at the European Southern Observatory’s Very Large Telescope in Chile to observe and document a short section of the shock front of the supernova SN 1006. This new technique is known as integral field spectroscopy – a first-time process which allows astronomers to thoroughly examine the composition of the light from the supernova remnant. Kevin Heng of the University of Bern, one of the supervisors of Nikolic’s doctoral work, says: “We are particularly proud of the fact that we managed to use integral field spectroscopy in a rather unorthodox way, since it is usually used for the study of high-redshift galaxies. In doing so, we achieved a level of precision that far exceeds all previous studies.”
It really is an intriguing time to be taking closer looks at supernovae remnants – especially in respect to cosmic rays. As Nikolic explains: “This was a pilot project. The emissions we observed from the supernova remnant are very, very faint compared to the usual target objects for this type of instrument. Now that we know what’s possible, it’s really exciting to think about follow-up projects.” Glenn van de Ven of the Max Planck Institute for Astronomy, Nikolic’s other co-supervisor and an expert in integral field spectroscopy, adds: “This kind of novel observational approach could well be the key to solving the puzzle of how cosmic rays are produced in supernova remnants.”
Kavli Institute Director Roger Blandford, who participated in the Fermi analysis, said, “It’s fitting that such a clear demonstration showing supernova remnants accelerate cosmic rays came as we celebrated the 100th anniversary of their discovery. It brings home how quickly our capabilities for discovery are advancing.”
