Former Canadian astronaut Chris Hadfield was on hand for the official circulation ceremony of Canada's new space-themed $5 bill on Nov. 7, 2013. The press conference took place in two locations; Hadfield was at the Canadian Space Agency headquarters near Montreal, Que. The red flower on his lapel is a poppy for Remembrance Day, a Nov. 11 commemoration of veterans. Credit: Bank of Canada (webcast/screenshot)
In Canada, “gimme five” could soon have a space connotation. Today the country announced it is preparing to put new polymer $5 bills into circulation that feature Canadian robotics and an astronaut.
At the official circulation ceremony near Montreal, Que. was none other than Canadian astronaut Chris Hadfield, who brought unprecedented social media attention to space through social media. The world was enchanted by his guitar playing and crying in space, but in space circles he also commands a lot of respect. The trilingual Hadfield visited two space stations, helped build the robotic Canadarm2 in space, and commanded the International Space Station, among other achievements.
His presence was appropriate, because the $5 bill has a lot of robotics on it. Canadarm2, Dextre and an astronaut are splashed across one face of the bill. “It reminds us that our dreams do not have a limit,” Hadfield said in French.
Canadarm2, Dextre and an unidentified astronaut on Canada’s new $5 bill. Credit: Bank of Canada
“It serves as a reminder to all Canadians of the dedication and hard work of so many people across the Canadian Space Agency and the space industry across Canada, and the scientists and engineers that make the design of these incredibly complex robots and getting them into space somehow easy,” Hadfield added in English. “Being involved in it is the real inspiration part. Who knows where such innovation can take us.”
The Bank of Canada first unveiled the new $5 and $10 bills in April, while Hadfield was at the helm of the station. Canada’s central banking authority is touting the new plasticized bill series as more durable than past cotton-based ones, with better counterfeit measures such as transparency. Polymer bills are available already in $20, $50 and $100 denominations.
Opposite to the space-themed side of the $5 bill is a picture of past prime minister Wilfrid Laurier. The new $10 bill features a train on one side and (as with the past iteration) John A. Macdonald, the first Canadian prime minister, on the other.
Hadfield himself has featured on both Canadian currency and stamps in the past: the Royal Mint of Canada issued two coins with him and Canadarm2 in 2006, and Hadfield was among several astronauts put on to Canadian stamps in 2003.
Canadian astronaut Chris Hadfield holds a version of the $5 bill on the International Space Station on April 30, 2013. Credit: Bank of Canada (webcast)
The 20-foot (6-meter) hole punched through the ice on Chebarkul Lake by a large fragment of the Chelyabinsk meteorite. Credit: AP
Security camera video showing the impact of the largest piece of the Chelyabinsk meteorite striking Lake Chebarkul during the Feb. 15, 2013 Russian fireball. Credit: Nikolaj Mel’nikov.
When I first watched this video of the half-ton Chelyabinsk meteorite crashing into Lake Chebarkul last Feb. 15 I didn’t see anything. But once you pay close attention, what you’ll see is nothing short of amazing. You’ll recall that a 20-foot (6 meter) hole appeared in the ice immediately after the fall. While no one witnessed the impact, a security camera caught the critical moment from the other side of the lake.
The video recently appeared in an online presentation by Peter Jenniskens, noted meteorite expert and senior research scientist at the SETI Institute. It was released as part of a paper and Powerpoint on the Chelyabinsk airburst. You can listen to Jenniskens’ presentation HERE.
Frame grab from the video showing the breakdown of the impact and resulting ice and snow cloud.
When you watch the video, focus your attention just to the left of what looks like an ice fishing shack at top center and use the handy frame grab above. In the slowed-down portion of the footage you’ll see a cloud of ice and snow blow up and quickly drift to the right of the shack seconds after impact. While blurry and small, it’s amazing good fortune we have a document of this fall.
Video of the recovery of the largest piece of the Chelyabinsk meteorite
Divers ultimately fished the 1/2 ton Chelyabinsk meteorite – the largest found so far – from the lake on Oct. 16. It measured 5 feet long (1.5 meter) and broke into three pieces as scientists hoisted it into a scale to weigh it.
As a return favor, the little piece of heaven broke the scale.
Pictures of asteroid P/2013 P5 taken by the Hubble Space Telescope. Credit: NASA, ESA, and D. Jewitt (UCLA)
A lawn sprinkler in space. That’s one of the descriptions NASA has for the curious P/2013 P5, which is spewing not one, not two, but six comet-like tails at the same time.
“We were literally dumbfounded when we saw it,” stated David Jewitt of the University of California at Los Angeles, who led the research. “Even more amazing, its tail structures change dramatically in just 13 days as it belches out dust. That also caught us by surprise. It’s hard to believe we’re looking at an asteroid.”
UCLA described the asteroid as a “weird and freakish object” in its own press release.
The mystery started when astronomers spotted a really blotchy thing in space Aug. 27 with the Pan-STARRS survey telescope in Hawaii. The Hubble Space Telescope then swung over to take a look on Sept. 10, revealing all these tails of debris flying off the asteroid.
Pan-STARRS PS1 Observatory just before sunrise on Haleakala, Maui. Credit: Harvard-Smithsonian Center for Astrophyiscs
It appears, scientists say, that the asteroid is rotating so quickly that it is ripping its very surface apart. They’ve ruled out a collision because the dust leaves in spurts; calculations by team member Jessica Agarwal of the Max Planck Institute for Solar System Research in Lindau, Germany estimated this happened on April 15, July 18, July 24, Aug. 8, Aug. 26 and Sept. 4.
Once the dust gets loose, the sun’s continuous stream of particles then pushes the debris into these extraordinary tails. It’s also possible that this “radiation pressure” contributed to the asteroid’s high spin rate. It appears the team is looking to find more of these objects to see if this is a way that smaller asteroids commonly fall apart.
“In astronomy, where you find one, you eventually find a whole bunch more,” Jewitt stated. “This is just an amazing object to us, and almost certainly the first of many more to come.”
The research appeared in Astrophysical Journal Letters and is also available in prepublished form on Arxiv.
Two new tail streamers are visible between Comet ISON's green coma and bright star near center. in this photo taken on Nov. 6. They're possibly the beginning of an ion tail. Click to enlarge. Credit: Damian Peach
I’m starting to get the chills about Comet ISON. I can’t help it. With practically every telescope turned the comet’s way fewer than three short weeks before perihelion, every week brings new images and developments. The latest pictures show a brand new tail feature emerging from the comet’s bulbous coma. For months, amateur and professional astronomers alike have watched ISON’s slowly growing dust tail that now stretches nearly half a degree or a full moon’s diameter. In the past two days, photos taken by amateur astronomers reveal what appears to be a nascent ion or gas tail. Damian Peach’s Nov. 6 image clearly shows two spindly streamers.
Early detection of ISON’s possible ion tail on Oct. 31 by amateur astronomer Efrain Morales Rivera in a 12-inch telescope.
The comet on Nov. 4 also shows the new tail structures extending farther from the coma. Credit: Justin Ng
Ion tails are composed of gases like carbon monoxide and carbon dioxide blown into a narrow straight tail by the solar wind and electrified to fluorescence by the sun’s ultraviolet light. Being made of ions (charged particles), they interact with the sun’s wind of charged particles. Changes in the intensity and direction of the magnetic field associated with sun’s exhalations kink and twist ion tails into strange shapes. Strong particle blasts can even snap off an ion tail. Not that a comet could care. Like a lizard, it grows a new one back a day or three later.
Comet ISON plunges sunward across Virgo in the coming days. Watch for it low in the eastern sky shortly before the start of dawn. Click to enlarge and print for outdoor use. Stellarium
A fresh forked tail isn’t ISON’s only new adornment. Its inner coma, location of the bright “false nucleus”, is becoming more compact, and the overall magnitude of the comet has been slowly but steadily rising. Two mornings ago I pointed a pair of 10×50 binoculars ISON’s way and was surprised to see it glowing at magnitude 8.5. Things happen quickly now that the comet is picking up speed While it appeared as little more than a small smudge, any comet crossing into binocular territory is cause for excitement. Other observers are reporting magnitudes as bright as 8.0. Estimates may vary among observers, but the trend is up. Seiichi Yoshida’s excellent Weekly Information about Bright Comets site predicts another half magnitude brightening over the next few days. You can use the map here to spot it in your own glass before the moon returns to the morning sky.
False color photo taken with the TRAPPIST 60-cm telescope using a narrowband CN (390 nm) filter at 8:45 Universal Time Nov. 5 shows two active jets (small double-plume) in ISON’s inner coma (right) and the dust tail at left. Field of view is 5×5 arc minutes. North is up, east to the left. Credit: Cyrielle Opitom, TRAPPIST team
But wait, there’s more. Emmanuel Jehin, a member of the TRAPPIST ( TRAnsiting Planets and PlanetesImals inSmall Telescopes) team, a group of astronomers dedicated to the detection of exoplanets and the study of comets and other small solar system bodies, reports a rapid rise in ISON’s gas production rate in the past several days. They’ve increased by a factor of two since Nov. 3. Could the spike be connected to the development of an ion tail? Jehin and team have also recorded two active jets coming from the comet’s nucleus using specialized filters. Dust production rates however have remained flat.
The Comet ISON Observing Campaign is both terrestrial and celestial. Nine different NASA and ESA spacecraft, eight of which are shown here, have observed comet ISON so far. Credit: NASA/ESA
Casey Lisse of the Comet ISON Observing campaign (CIOC) reports that the Chandra X-ray Observatory just became the 9th spacecraft to image the comet . More details and photos should be available soon. The campaign predicts the comet will peak in brightness between -3 to -5 magnitude when it zips closest to the sun on Nov. 28. Want to ride alongside the comet during its passage through the inner solar system? Click on this awesome, interactive simulator.
Hubble Space Telescope image of comet C/1999 S4 (LINEAR) that disintegrated around July 23, 2000. Credit: NASA/ESA
Because ISON is a fresh-faced visitor from the distant Oort Cloudthat will soon face the full fury of the sun, speculation of its fate has ranged across the spectrum. Everything from breakup and dissolution before perihelion to surviving intact trailing a spectacular dust tail. The comet is currently approaching the 0.8 A.U. mark (74.4 million miles / 120 million km) when previous comets C/1999 S4 LINEAR in 2000 and C/2010 X1 Elenin in 2011 crumbled to pieces and vaporized away. Will ISON have the internal strength to pass the test and venture further into the solar boil? Should it survive, it faces a formidable foe – the sun. Both the intense solar heat and gravitational stress on the comet’s nucleus could easily tear it apart. If this happens a few days before perihelion we’ll be left with little to see, but if ISON busts up a day or two after perihelion, watch out baby. When the comet reappears in the morning sky, it may be missing its head but make it up for the loss with a spectacular tail of fresh dust and ice many degrees in length. This is exactly what happened to Comet C/2011 W3 (Lovejoy) in December 2011. After its close graze with the home star, the nucleus disintegrated, producing a striking tail seen by skywatchers in the southern hemisphere.
Pictures of Comet C/2011 W3 Lovejoy on Dec. 22, 2011 after perihelion passage. Will ISON be a repeat? Credit: Chris Wyatt
The final scenario sees Comet ISON pushing past all barriers intact and ready to put on a splendid show. Whatever happens, I suspect we’re in for surprises ahead. For a more detailed analysis of these possibilities I invite you check out Matthew Knight’s blog on the CIOC website.
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
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[/caption]
With India’s Mars Orbiter Mission (MOM) safely and flawlessly injected into her initial elliptical Earth parking orbit following Tuesday’s (Nov. 5) spectacular launch, the flight has quickly transitioned to the next stage – the crucial series of thruster firings to raise MOM’s orbit around Earth dubbed “Midnight Maneuvers” and achieve escape velocity.
Barely a day after blastoff, ISRO engineers successfully completed the first of six orbit raising “Midnight Maneuver” burns at 01:17 hrs IST today (Nov. 6) with MOM’s liquid fueled thruster – see graphic below.
The goal is to gradually maneuver MOM – India’s 1st mission to the Red Planet – into a hyperbolic trajectory so that the spacecraft will escape from the Earth’s Sphere of Influence (SOI) and eventually arrive at the Mars Sphere of Influence after a 10 month interplanetary cruise. Artists concept shows First Midnight Manouever of ISRO’s Mars Orbiter Mission Spacecraft with successful thruster firing of the liquid engine on Nov. 6 2013. Credit: ISRO
To do this involves a lot of complicated orbital mechanics calculations, as noted by ISRO’s chief during the launch webcast.
“The journey has only begun. The challenging phase is coming,” said Dr. K. Radhakrishnan, Chairman ISRO.
India’s PSLV rocket is not powerful enough to send MOM on a direct flight to Mars.
The launch “placed MOM very precisely into an initial elliptical orbit around Earth of 247 x 23556 kilometers with an inclination of 19.2 degrees,” said Radhakrishnan. “MOM is a huge step taking India beyond Earth’s influence for the first time.”
So ISRO’s engineers devised a clever procedure to get the spacecraft to Mars on the least amount of fuel via six “Midnight Maneuver” engine burns over the next several weeks – and at an extremely low cost.
First orbit raising Midnight Manouever of ISRO’s Mars Orbiter Mission Spacecraft completed successfully. Credit: ISRO
The 440 Newton engine fires when MOM is at its closest point in orbit above Earth. This increases the ships velocity and gradually widens the ellipse and raises the apogee of the six resulting elliptical orbits around Earth that eventually injects MOM onto the Trans-Mars trajectory.
The 1st firing lasted 416 seconds and raised the spacecraft’s apogee to 28,825 km and perigee to 252 km.
The remaining burns are planned for November 7, 8, 9, 11, and 16.
MOM is expected to achieve escape velocity on Dec. 1 and depart Earth’s sphere of influence tangentially to Earth’s orbit to begin the 300 day long voyage to the Red Planet.
She will follow a path that’s roughly half an ellipse around the sun.
MOM arrives in the vicinity of Mars on September 24, 2014 for the absolutely essential Mars orbital insertion firing by the 440 Newton liquid fueled main engine which slows the probe and places it into a 366 km x 80,000 km elliptical orbit.
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).
MOM is the first of two new Mars orbiter science probes from Earth blasting off for the Red Planet this November. Half a globe away, NASA’s $671 Million MAVEN orbiter remains on target to launch barely two weeks after MOM on Nov. 18 – from Cape Canaveral, Florida.
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 told Universe Today.
Stay tuned here for continuing MOM and MAVEN news and Ken’s MAVEN launch reports from on site at the Kennedy Space Center press center.
Here’s a glorious gallery of launch images of the PSLV-25 rocket & Mars Orbiter Mission (MOM) on Nov. 5, 2013.
It’ s a Mind-Blowing Midnight Marvel ! Fueled PSLV rocket and India’s Mars Orbiter Mission (MOM) awaits Nov. 5 blastoff. Credit: ISRO.Gorgeous view of the majestic Polar Satellite Launch Vehicle, PSLV C25 with its passenger, the Indian Space Research Organization’s (ISRO’s) Mars Orbiter Mission (MOM) spacecraft inside. The Mobile service tower is also seen in the background. Credit: IRSOBlastoff of the Indian developed Mars Orbiter Mission (MOM) on Nov. 5, 2013 from the Indian Space Research Organization’s (ISRO) Satish Dhawan Space Centre SHAR, Sriharikota. Credit: ISROSurreal view of ‘T zero’
Launch of India’s Mars Orbiter Mission (MOM) on Nov. 5, 2013. Credit: ISROGolden smoke engulfs the First Launch Pad as the PSLV C25 takes off with ISRO’s Mars Orbiter Mission Spacecraft. Credit: ISROCelebrating MOM’s Victory over Gravitation !
There she goes taking our dreams into deeper space ! Launch of India’s Mars Orbiter Mission (MOM) on Nov. 5, 2013. Credit: ISROClouds 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: ISROIndia’s Mars Orbiter Mission (MOM) streaks to orbit after launch on Nov. 5, 2013. Credit: ISRO
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Learn more about MAVEN, MOM, Mars rovers, Orion and more at Ken’s upcoming presentations
Nov 14-19: “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 Soyuz TMA-11M rocket is launched with Expedition 38/39. Credit: NASA/Bill Ingalls.
Update: the crew has now arrived safely at the ISS. You can watch the arrival video below.
Three new crew members are on their way to the International Space Station. NASA astronaut Rick Mastracchio, Japan Aerospace Exploration Agency astronaut Koichi Wakata and Soyuz Commander Mikhail Tyurin of Roscosmos launched on a Soyuz TMA-11M spacecraft from the Baikonur Cosmodrome at 11:14 p.m. EST (04:14:00 UTC, 10:14 a.m. Thursday, Kazakh time). They’ll use the accelerated “fast-track” trajectory and arrive at the station in just a few hours, at 10:31 UTC (5:31 a.m. EST Thursday.)
You can watch the launch video below.
In an usual situation, when the new crew arrives, there will be nine crew members and three Soyuz vehicles at the ISS. The timing of crew exchange works to enable a complicated “relay race” of a special Olympic torch from the 2014 Sochi Winter Olympics in Russia. The new crew is bringing the unlit torch along, then, over the weekend Russian cosmonauts Oleg Kotov and Sergei Ryazanskiy, who are part of the space station’s current crew, will take the torch out on a spacewalk, with plans to take pictures and video (they’ll try to take pictures when the station flies over Russia and the southern resort of Sochi). The real reason for the spacewalk is to do some routine Russian maintenance outside the station.
The Soyuz TMA-11M spacecraft launches from the Baikonur Cosmodrome with the crew of Expedition 38. Via NASA TV.
Then, on Sunday, three crew members will return home (Fyodor Yurchikhin, Luca Parmitano and Karen Nyberg) and they will bring the torch back home, with landing planned at about 9:50 p.m. EST on Nov 10 (02:50 UTC on Nov 11.) The torch then will be given back to Olympic officials and it will be used in the opening ceremonies of the February games.
After that crew departs, Expedition 38 will begin with Kotov as Commander.
Nine crew members together on the International Space Station. The Expedition 38 crew entered the ISS at 12:44 UTC (7:44 am EST). The crew of nine will work together till Sunday. Credit: NASA
There have not been nine crew members on the ISS since 2009. During the second half of the new crew’s Expedition, when it changes to Expedition 39, Wakata will make history by becoming the first Japanese commander of the International Space Station. You can read more about Wakata and Mastracchio and their upcoming mission in an interview they did with Elizabeth Howell during their training.
The new fast-track trajectory has the Soyuz rocket launching shortly after the ISS passes overhead. Then, additional firings of the vehicle’s thrusters early in its mission expedites the time required for a Russian vehicle to reach the Station, in about 6 hours or four orbits.
A solar halo seen over Klerksdorp, South Africa. Credit:
Daniël Engelbrecht
Fresh off seeing a solar eclipse on Sunday, people across the southern parts of Africa witnessed another solar spectacle today, a sun halo. “It was so beautiful, everyone was taking pictures and sharing them on Facebook,” said Daniël Engelbrecht from Klerksdorp, South Africa, sending in his picture to Universe Today via email.
These halos are quite the sight to see, but unlike an eclipse, they can’t be predicted. Conditions in the atmosphere have to be just right, with moisture or ice crystals creating a “rainbow” effect around the Sun. Sometimes the halos surround the Sun completely, other times, they appear as arcs around the Sun creating what is known as sundogs. Basically, sunlight is reflecting off moisture in the atmosphere.
Ice crystals in Earth’s atmosphere can also cause rings around the Moon, and moondogs(as well as sundogs) and even Venus pillars. News reports indicate sun halos were seen just a few days ago in Africa as well, on Nov. 1, 2013.
A few other people sent in images from their phones, too of today’s sun halo:
Image of a Sun halo seen over Botswana, Southern Africa at 11:08 am local time on Nov, 6, 2013. Taken with an iPhone. Credit: Belleminah K Chitonho.Image of a Sun halo taken at 12:10 on Nov. 6, 2013, in northwest South Africa, in Mmabotho with a blackberry phone. Credit: Vanessa Lucher.
Two nascent black holes formed by the collapse of an early supergiant star. From a visualization by by Christian Reisswig (Caltech).
It’s one of the puzzles of cosmology and stellar evolution: how did supermassive black holes get so… well, supermassive… in the early Universe, when seemingly not enough time had yet passed for them to accumulate their mass through steady accretion processes alone? It takes a while to eat up a billion solar masses’ worth of matter, even with a healthy appetite and lots within gravitational reach. But yet there they are: monster black holes are common within some of the most distant galaxies, flaunting their precocious growth even as the Universe was just celebrating its one billionth birthday.
Now, recent findings by researchers at Caltech suggest that these ancient SMBs were formed by the death of certain types of primordial giant stars, exotic stellar dinosaurs that grew large and died young. During their violent collapse not just one but two black holes are formed, each gathering its own mass before eventually combining together into a single supermassive monster.
Watch a simulation and find out more about how this happens below:
To investigate the origins of young supermassive black holes, Christian Reisswig, NASA Einstein Postdoctoral Fellow in Astrophysics at Caltech and Christian Ott, assistant professor of theoretical astrophysics, turned to a model involving supermassive stars. These giant, rather exotic stars are hypothesized to have existed for just a brief time in the early Universe.
Unlike ordinary stars, supermassive stars are stabilized against gravity mostly by their own photon radiation. In a very massive star, photon radiation—the outward flux of photons that is generated due to the star’s very high interior temperatures—pushes gas from the star outward in opposition to the gravitational force that pulls the gas back in.
During its life, a supermassive star slowly cools due to energy loss through the emission of photon radiation. As the star cools, it becomes more compact, and its central density slowly increases. This process lasts for a couple of million years until the star has reached sufficient compactness for gravitational instability to set in and for the star to start collapsing gravitationally.
Previous studies predicted that when supermassive stars collapse, they maintain a spherical shape that possibly becomes flattened due to rapid rotation. This shape is called an axisymmetric configuration. Incorporating the fact that very rapidly spinning stars are prone to tiny perturbations, Reisswig and his colleagues predicted that these perturbations could cause the stars to deviate into non-axisymmetric shapes during the collapse. Such initially tiny perturbations would grow rapidly, ultimately causing the gas inside the collapsing star to clump and to form high-density fragments.
“The growth of black holes to supermassive scales in the young universe seems only possible if the ‘seed’ mass of the collapsing object was already sufficiently large.”
– Christian Reisswig, NASA Einstein Postdoctoral Fellow at Caltech
Composite image from Chandra and Hubble showing supermassive black holes in the early Universe.
These fragments would orbit the center of the star and become increasingly dense as they picked up matter during the collapse; they would also increase in temperature. And then, Reisswig says, “an interesting effect kicks in.” At sufficiently high temperatures, there would be enough energy available to match up electrons and their antiparticles, or positrons, into what are known as electron-positron pairs. The creation of electron-positron pairs would cause a loss of pressure, further accelerating the collapse; as a result, the two orbiting fragments would ultimately become so dense that a black hole could form at each clump. The pair of black holes might then spiral around one another before merging to become one large black hole.
“This is a new finding,” Reisswig says. “Nobody has ever predicted that a single collapsing star could produce a pair of black holes that then merge.”
The mineral olivine on Vesta, as seen from hyperspectral data received during the Dawn mission. Credit: Image generated by Alessandro Frigeri and Eleonora Ammannito using VIR data and Framing Camera images.
That ghoul-like sheen on the asteroid Vesta, as seen in the image above, is not some leftover of Hallowe’en. It’s evidence of the mineral olivine. Scientists have seen it before in “differentiated” bodies — those that have a crust and an inner core — but in this case, it’s turning up in an unexpected location.
Finding olivine is not that much of a surprise. Vesta is differentiated and also (likely) is the origin point of diogenite meteorites, which are sometimes olivine-rich. Researchers expected that the olivine would be close to the diogenite rocks, which in Vesta’s case are in areas of the south pole carved out from the mantle.
NASA’s Dawn mission to the asteroid did a search in areas around the south pole — “which are thought to be excavated mantle rocks”, the researchers wrote — but instead found olivine in minerals close to the surface in the northern hemisphere. These minerals are called howardites and are normally not associated with olivine. So what is going on?
Artist’s conception of the Dawn mission. Credit: NASA
Basically, it means that Vesta’s history was far more complex than we expected. This situation likely arose from a series of impacts that changed around the eucritic (stony meteorite) crust of Vesta:
“A generalized geologic history for these olivine-rich materials could be as follows: ancient large impacts excavated and incorporated large blocks of diogenite-rich and olivine-rich material into the eucritic crust, and subsequent impacts exposed this olivine-rich material,” the researchers wrote.
“This produced olivine-rich terrains in a howarditic background, with diogene-rich howardites filling nearby, eroded, older basins.”
Dawn, by the way, has completed its time at Vesta and is now en route to another large asteroid, Ceres. But there’s still plenty of data for analysis. This particular research paper was led by E. Ammannito from the Institute of Astrophysics and Space Planetology (Istituto di Astrofisica e Planetologia Spaziali) in Rome. The research appears in this week’s Nature and should be available shortly at this link.
“What’s that bright object to the southwest at dusk?” We’ve already fielded more than a few such questions as Earth’s sister world shines in the dusk sky. Venus just passed its maximum elongation 47 degrees east of the Sun on November 1st, and currently shines at a brilliant magnitude -4.46. This is almost 16 times brighter than the brightest star in the sky, -1.46th magnitude Sirius.
Venus and the waxing crescent Moon, looking to the west tonite at 30 minutes after sunset for latitude 30 degrees north. (Created using Stellarium).
Just like the Moon, Venus goes through a full range of phases. Through the telescope, Venus currently presents a 26.7” diameter disk. That size will swell to almost 40” by month’s end, as Venus begins to approach the Earth and presents a noticeable crescent phase. We just passed dichotomy — the theoretical point where Venus presents a half-illuminated phase as seen from Earth — on October 31st, and Venus already shows a noticeable crescent:
Venus on the night of November 5th 2013, a quick stack of about 200 frames. (Photo by Author)
Note that we say “theoretical” because there’s typically a discrepancy of a day or two between predicted and observed dichotomy. This is also known as Schröter’s Effect. One probable cause for this is the dazzling appearance of the disk of Venus. We typically use a variable polarizing filter to cut the glare of Venus down at the eyepiece.
You might also note that Venus currently occupies the “basement” of the zodiac in the constellation Sagittarius. In fact, the planet is currently as far south as it can go, sitting at a declination of -27° 14’ on this very evening. You have to go all the way back to 1930 to find a more southerly declination of Venus, just 12’ lower!
But you won’t have to wait much longer to break that record, as the chart below shows for the most southerly declinations of Venus for the next half century:
Year
Date
Declination
2013
November 6th
-27° 09’
2021
“ “
-27° 14’
2029
“ “
-27° 18’
2037
“ “
-27° 23’
2045
“ “
-27° 29’
2053
“ “
-27° 34’
2061
“ “
-27° 39’
Note that each event occurs on November 6th, and they’re spaced 8 years apart. Apparitions of Venus closely duplicate their paths in the sky over an 8 year cycle. This is because the planet nearly completes 13 orbits of the Sun for our 8. Venus “catches up” to the Earth on its interior orbit once every 584 days to reach inferior conjunction. It usually passes above or below the Sun from our vantage point, though last year it transited, a feat that won’t be witnessed again until 2117 AD.
How far south can Venus go? Well, its orbit is tilted 3.4 degrees relative to the ecliptic. It can reach a southern declination of -28 05’, though you have to go way back to 1874 for its last occurrence!
Today is also a great time to try your hand at spotting Venus in the daytime, as a 3-day old waxing crescent Moon lies about eight degrees to its upper right:
A daytime Venus near the Moon, transiting to the south at about 3:30PM EST today. A 5 degree wide Telrad “bullseye” is provided for scale. (Credit: Stellarium).
Note that seeing Venus in the daytime is surprisingly easy, once you known exactly where to look for it. Your best chances are around mid-afternoon at about 3PM local, when the daytime Moon and Venus lie highest in the southern sky. Did you know that Venus is actually intrinsically brighter per square arc second than the Moon? It’s true! The Moon actually has a very low reflective albedo of 12% — about the equivalent of fresh asphalt — while the cloud tops of Venus are more akin the fresh snow with an albedo of about 80%.
Its also worth checking out Venus and its local environs after nightfall as it passes near the Lagoon (M8) and the Trifid nebula (M8) on the night of November 6th. Continuing with its trek across the star rich plane of the heart of the Milky Way galaxy, Venus also passes near the globular cluster M22 on November 13th.
Venus also sits in the general of Pluto on November 15th, lying just 6.6 degrees south of it. Be sure to wave in the general direction of NASA’s New Horizons spacecraft bound for Pluto in July 2015 tonight as well, using the Moon and Venus for a guide:
The position of the Moon, Venus, Pluto, & New Horizons at 14UT on November 7th, 2013. (Created using Starry Night Education Software).
Another shot at seeing Venus paired with the Moon occurs on December 5th.
Venus also presents a maximum area of illumination on December 6th, and will shine at its brightest on December 10th at magnitude -4.7. Can you catch it casting a shadow? The best time to search for this illusive phenomenon would be just before New Moon on December 2nd. A dark sky site away from any other sources of illumination, and a snow covered ground providing high contrast also helps. Fortunately, snow isn’t in short supply in the northern hemisphere in December!
Venus is currently the only naked eye planet in the November early evening sky. We always thought that it’s a bit of a cosmic irony that the nearest planet presents a dazzling, but featureless white disk as seen from Earth. Diligent amateurs have, however, been able to tease out cloud patterns on Venus using UV filters.
Another elusive phenomenon to watch for as Venus reaches a crescent phase is ashen light. Long reported by observers, a faint glow on the night side of Venus is something that persists, but shouldn’t be. A similar effect seen on the night side of the Moon known as Earthshine is easily explained by sunlight being reflected off of the Earth… but Venus has no moon. What gives? Frequent explanations over the years have been aurorae, electrical activity, airglow, or, more frequently cited, observer bias. The brain wants to see a filled in space, and promptly inserts it betwixt the dazzling horns of the planet.
Keep an eye on Venus as it reaches maximum brilliancy and heads towards inferior conjunction on January 11th, 2014, and a rare chance to see it on said date… more to come!
