Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.
This Rosetta image of Comet 67P/Churyumov-Gerasimenko shows spectacular jets erupting from the small body on Sept. 10, 2014. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Jet! The comet that the Rosetta spacecraft is visiting is shedding more dust as machine and Solar System body get closer to the Sun.
While activity was first seen at the “neck” of the rubber-duckie shaped comet a few weeks ago, now scientists are seeing jets spring from across the comet.
This is just one signal of cometary activity picking up as 67P gets closer to the Sun. For the moment, it appears the prime landing site is still safe enough for Philae to land on Nov. 19, officials said, while noting there is a jet about a kilometer away that the lander can study when it gets there.
Jets spring from the “neck” area of Comet 67P/Churyumov-Gerasimenko. The smaller lobe is on the left, and the larger on the right. These images were taken about 7.2 kilometers (4.5 miles) from the surface. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
“At this point, we believe that a large fraction of the illuminated comet’s surface is displaying some level of activity,” stated Jean-Baptiste Vincent a scientist from the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) that took the pictures. He is with the Max Planck Institute for Solar System Research in Germany.
The comet is about 470 million kilometers (292 miles) from the Sun and will make its closest approach in 2015. Rosetta is the first mission to orbit a comet as it gets close to the Sun, and Philae (if successful) will make the first “soft” landing on a cometary surface.
Comet Siding Spring near Mars in a composite image by the Hubble Space Telescope, capturing their positions between Oct. 18 8:06 a.m. EDT (12:06 p.m. UTC) and Oct. 19 11:17 p.m. EDT (Oct. 20, 3:17 a.m. UTC). Credit: NASA, ESA, PSI, JHU/APL, STScI/AURA
We’ve seen spectacular images of Comet Siding Spring from Mars spacecraft, showing just how close the small body was to the Red Planet when it whizzed by Sunday (Oct. 19). But how close were the two objects actually, in the sky? This Hubble Space Telescope composite image shows just how astoundingly near they were.
Above are two separate exposures taken Oct. 18-19 EDT (Oct. 18-20 UTC) against the same starry field image from another survey. It was a complicated shot to get, NASA explains, but it does serve as a powerful illustration of the celestial close encounter.
“This is a composite image because a single exposure of the stellar background, comet Siding Spring, and Mars would be problematic. Mars is actually 10,000 times brighter than the comet, and so could not be properly exposed to show detail in the Red Planet,” NASA stated.
High resolution image pairs made with HiRISE camera on MRO during Comet Siding Spring’s closest approach to Mars on October 19. Shown at top are images of the nucleus region and inner coma. Those at bottom were exposed to show the bigger coma beginning of a tail. Credit: NASA/JPL/Univ. of Arizona
“The comet and Mars were also moving with respect to each other and so could not be imaged simultaneously in one exposure without one of the objects being motion blurred. Hubble had to be programmed to track on the comet and Mars separately in two different observations.”
The two images were blended together in this single shot, showing their separation of 1.5 arc minutes (1/20 of the Moon’s apparent diameter.) The background stars comes from data from the Palomar Digital Sky Survey “reprocessed to approximate Hubble’s resolution”, NASA stated.
While the nucleus is too small to be imaged by Hubble, you can see what it looks like in the image above from the Mars Reconnaissance Orbiter. Siding Spring passed by the Red Planet at a distance of just 87,000 miles (140,000 km).
Six images that combine Chandra data with those from other telescopes. Credit: X-ray: NASA/CXC/SAO, Optical: NASA/STScI, Radio: NSF/NRAO/VLA).
What a gem! This huge black hole in the middle of Hercules A is making gas around it super-heated to millions of degrees, making it shine brightly in X-Rays. The Chandra X-Ray Telescope captured the scene and in a new data release this week, telescope officials cracked open the archives to give us gems such as this.
The release comes as a part of American Archives Month, where every year Chandra officials go through the archives and pull out old Chandra data, combining it with the work of other telescopes to get as much information as possible about the objects being studied.
Chandra is one of three NASA “Great Observatories” still active, with the other two being the Hubble Space Telescope and the Spitzer Space Telescope. It’s been in operation now for more than 15 years.
You can see the six new pictures below. To read more about each of these objects, head on over to this link.
Six photos released from the Chandra X-Ray Observatory’s archive in October 2014. Credit: NASA/CXC/SAO
A 3-D image of "Wdowiak Ridge" on Mars, based on images from the left and right side of the Opportunity rover's Pancam. Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.
Grab your 3-D glasses (you do have a pair handy, right?) and take a look at this latest vista from Mars. This is a view taken by the Opportunity rover that looks at a location nicknamed “Wdowiak Ridge”, on the rim of Endeavour Crater.
This mosaic was obtained Sept. 17 as Opportunity continued its journey to “Marathon Valley”, a spot that could hold clays (which would indicate a water-rich environment in the past.) The rover is more than a decade into its mission and has been sending back images amid battling Flash memory problems lately.
“Wdowiak Ridge sticks out like a sore thumb. We want to understand why this ridge is located off the primary rim of Endeavour Crater and how it fits into the geologic story of this region,” stated Jim Rice, the Opportunity science-team of the Planetary Science Institute in Arizona.
More specifically, the team is interested in why this ridge is so prominent and sharp — they are calling it one of the most distinctive features Opportunity has ever seen. How it resisted erosion in an area so worn down is one thing scientists are hoping to learn about.
A Martian mosaic showing “Wdowiak Ridge”, which the Opportunity rover imaged Sept. 17, 2014. The rover’s tracks are visible at right. Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.
The last Opportunity rover update talks about activities through Sept. 30, but NASA has released raw images available since then. Check out a selection below.
Is this an image of Comet Siding Spring? It’s the only fuzzy object in the field photographed on Sol 3817 (October 19) by the Opportunity Rover. Click for original raw image.The Opportunity rover at work on Mars on Sol 3,817 in October 2014. Credit: NASA/JPL-CaltechAn image of Martian terrain with the Opportunity’s rover solar panel just visible at the bottom of the panel. Picture taken Sol 3,817 in October 2014. Credit: NASA/JPL-CaltechA dramatic, shadowy picture showing part of the Opportunity rover on Mars lit by the Sun (at top). Picture taken Sol 3,812 in October 2014. Credit: NASA/JPL-CaltechThe Opportunity rover’s tracks dominate this image taken on Mars on Sol 3,807 in October 2014. Credit: NASA/JPL-Caltech
A radar view of Venus taken by the Magellan spacecraft, with some gaps filled in by the Pioneer Venus orbiter. Credit: NASA/JPL
Talk about using old data for a new purpose! Researchers re-examining information from the completed NASA Magellan mission found signs of what could be “heavy metal” frost on the hell-like surface. What the researchers saw in radio-wave reflectance is the highlands appear brighter, with dark spots in the tallest locations.
What substance exactly is causing the patches on the surface is unknown, and it is extremely hard to make predictions given the difficulty of simulating Venus’ 900-degree Fahrenheit (500-degree Celsius) surface temperature, which is also 90 times Earth’s air pressure at sea level.
“Like on Earth, the temperature changes with elevation,” stated Elise Harrington, an Earth sciences undergraduate at British Columbia’s Simon Fraser University who led the research. “Among the possibilities on Venus are a temperature dependent chemical-weathering process or heavy metal compound precipitating from the air – a heavy metal frost.”
Venus’ volcano Sapas Mons, which was imaged by the Magellan mission in 1991. Credit: NASA
Scrutiny of a previously examined area on Venus, the Odva Regio highlands, saw a low radar reflection at 2,400 meters (7,900 feet), which progressively gets brighter until dark spots begin appearing and reflections drop at 4,700 meters (15,400 meters).
While previous research spotted a few of these patches, Harrington and supervisor Allan Treiman (Lunar and Planetary Institute) saw hundreds. There’s no radar-imaging spacecraft in orbit around Venus right now, but the authors hope that the finding will generate more interest in this planet. (Of note, the European Space Agency’s Venus Express is finishing up a mission there now, which included several daring atmosphere-skimming maneuvers earlier this year.)
The research was presented at the Geological Society of America meeting in Vancouver, British Columbia.
Frost deposits in Louth Crater appears to remain through the year, as found in Mars Reconnaissance Orbiter HiRISE photos of the region. Credit: NASA/JPL/University of Arizona
Mars was once thought to be a fairly unchanging planet, similar to the Moon. But now we know it is a planet that was shaped by water and other forces in the past — and that these forces still come into play today.
Above is a picture of permafrost deposits just discovered in Louth Crater. This find comes from NASA’s Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE) and you can see some of its latest water- and dust- shaped environments imaged below.
“A still-unexplained feature of this crater is the diffuse dark smudges visible on the crater floor,” read an update on the University of Arizona HiRISE website explaining this image. “These resemble ‘defrosting spots’ which are visible on carbon dioxide ice in the early spring, but they occur on frost-free areas and survive throughout the summer.”
The frost was caught in a HiRISE image early in the summer, and it persisted as controllers watched it through the summer — indicating that it is permanent. Its size did diminish somewhat, however. Scientists are pretty sure that this is water ice, as carbon dioxide can’t survive the summer.
See more new HiRISE photos below.
A close-up of “chaotic terrain” in Valles Marineris imaged by the Mars Reconnaissance Orbiter’s HiRISE camera. Wind or fluid may have further shaped this region, which could be related to possible signs of an ancient lake found in other regions of Valles Marineris. Credit: NASA/JPL/University of ArizonaA section of the vast Valles Marineris ravine called Melas Chasma, a spot where sulfates (minerals formed in water) have been found before. The image shows layers of deposits that were formed before and after the formation of Valles Marineris. Credit: NASA/JPL/University of ArizonaA section of Eastern Elysium Planitia imaged by the Mars Reconnaissance Orbiter’s HiRISE camera showing a possible old lava field near dust avalanches stirred up more recently. Credit: NASA/JPL/University of Arizona
This colorized mosaic from NASA's Cassini mission shows the most complete view yet of Titan's northern land of lakes and seas. Saturn's moon Titan is the only world in our solar system other than Earth that has stable liquid on its surface. The liquid in Titan's lakes and seas is mostly methane and ethane. Image credit: NASA/JPL-Caltech/ASI/USGS
There’s a very early-stage NASA concept to take a submarine and dive into a lake of Titan, that moon of Saturn that has chemistry that could prove to be a similar precursor to what eventually formed life on Earth. The moon has weather and a hydrological system and an atmosphere, making it an exciting location for astrobiologists.
Luckily for scientists, the Cassini spacecraft beams back regular updates on what it sees at Titan. And this week comes yet another opportunity, as the machine whizzes by the moon to look for “mirror-like surface echoes” in a lake-filled region in Titan’s northern sector.
Principal among the targets will be Kraken Mare, a liquid hydrocarbon sea that is about five times the size of Lake Superior in North America. It’s an astounding 154,000 square miles (400,000 square kilometers). On this pass, Cassini is going to sail over the eastern area of the sea.
“Measurements of the absolute strength of the echo and its polarization properties, when detectable, yield important information about the surface status (liquid/solid), surface reflectivity, surface dielectric constant and implied composition, and surface roughness,” Cassini’s website says in a description of the T-106 flyby, which will take place Thursday (Oct. 23).
Saturn’s moon Titan with Tethys hovering in the background. Image taken by the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute
This is the second-to-last flyby Cassini will have of Titan in 2014, with the last one coming Dec. 10. In that case, the focus will be learning more about Titan’s atmosphere to learn more about measurement differences obtained by instruments on Cassini.
This past week, meanwhile, Titan has been busy looking at Saturn. It examined a northern aurora, looked at the planet’s F ring, and also searched for small satellites.
Scientists have been working at Saturn for the past 10 years with the Cassini mission, which is now entering a new phase as Saturn enters northern summer. This is expected to produce more changes on Titan, such as winds picking up, as more sunlight strikes the surface and atmosphere.
The Rosetta spacecraft takes a selfie Oct. 7 with its target, 67P/Churyumov–Gerasimenko, from an altitude of about 9.9 miles (16 kilometers). Credit: ESA/Rosetta/Philae/CIVA
The Philae spacecraft has a tough job ahead of it on November 12: it is slated to make the first landing on a comet’s surface. Riding piggyback on the Rosetta spacecraft, all indications are it is in good health and ready for the job; the team has even been taking the time for Philae to image spacecraft “selfies” with its target, Comet 67P/Churyumov–Gerasimenko, in the background.
And Rosetta will also be working hard, as the animation above shows us with the various maneuvers the spacecraft will be required to send Philae to the surface. Read more about these orbital changes below, as well as details of a contest to name the comet’s landing site.
As you can see in the animation, Rosetta starts in a 19 kilometer (11.8 mile) orbit, then moves down to the 10 km (6.2 mile) mapping orbit that it is right now.
Rosetta then does some maneuvers to get ready to send Philae to the surface, including a trajectory change about 2-3 hours before Philae’s landing. Rosetta will be about 22.5 km (14 miles) from the comet during the pre-separation phase. Then, the latter part of the animation shows Rosetta moving around to orbits ranging between 20 km and 50 km (12.4 miles and 18.6 miles) through December.
Meanwhile, here’s another way that certain people can get involved in the mission: the European Space Agency has a naming contest for the prime landing site!
“The rules are simple: any name can be proposed, but it must not be the name of a person,” ESA stated. “The name must be accompanied by a short description (up to 200 words) explaining why this would make the ideal name for such an historic location.”
Full contest rules and details are available here. Hurry as the deadline is Oct. 22!
A false-color view of Saturn's moon Hyperion taken during a Cassini flyby in September 2005. Credit: NASA/JPL-Caltech/Space Science Institute
Ever taken a balloon and rubbed it against your hair? That’s an example of electrostatic charging, which you see as the balloon briefly attracts strands of hair against your head. Turns out a similar process is taking place on Saturn’s moon Hyperion. More astounding, it wasn’t until recently that scientists saw a curious effect on the Cassini spacecraft in 2005.
As the machine whizzed by the small moon, Cassini was blanketed in electrons from Hyperion’s electrostatically charged surface. It’s the first time scientists have seen static electricity in effect on any airless body outside of the Moon.
The charge comes partly from massive Saturn’s magnetic field, which hits Hyperion’s spongy surface constantly with electrons and ions. The Sun also plays a role, sending ultraviolet light that also strikes the moon’s surface. Scientists found out this happens while studying old data on the Cassini spacecraft, when they discovered “something unexpected” during a close flyby of Hyperion in September 2005.
NASA’s Cassini spacecraft obtained this unprocessed image of Saturn’s moon Hyperion on Aug. 25, 2011. Image credit: NASA/JPL-Caltech/Space Science Institute
Specifically, the spacecraft — which is still in operation today — was briefly connected through magnetism to Hyperion’s surface, receiving a surge of electrons. Cassini emerged from the encounter unharmed, even though team members estimate that it received the equivalent of a 200-volt shock from the moon. Charging events can hurt spacecraft, making this a valuable thing to know about for future missions.
“Our observations show that this is also an important effect at outer planet moons and that we need to take this into account when studying how these moons interact with their environment,” stated Geraint Jones of Mullard Space Science Laboratory (MSSL), University College London. He is a member of the Cassini Plasma Spectrometer (CAPS) team and one of the study’s supervisors.
CAPS is not in operation any more, since the instrument was turned off due to drawing excess current in 2012. But perhaps some of its past data, and observations from other Cassini instruments, can help unveil evidence of charging on other moons.
The tumbling motion of elongated Eros creates a changing brightness. (via transitofvenus.nl)
Previous research concerning some of Saturn’s moons, and the asteroid Eros, suggests that charged dust can move across the surface and perhaps even be able to sail into space against the force of gravity.
Several other instruments were used to gather data for this analysis, including Cassini’s magnetometer, magnetospheric imaging instrument, and radio and plasma wave science instrument.
You can read more about the research, which was led by Tom Nordheim, an MSSL doctoral candidate, in Geophysical Research Letters.
The International Space Station is bathed in a green laser as part of a communications test at the European Space Agency's optical ground station in Spain. Credit: ESA (screenshot)
Woah, is that home to six people in space now some sort of a ghoul? Here is a video of the International Space Station in an odd shade of … green. And no, it’s not because astronauts secretly painted the hull during their spacewalk this week.
What you’re actually seeing is a green laser shining on the space station as part of a test of next-generation communications technologies. Lasers have been used in successful tests to the Moon and the space station in the past year, hinting that perhaps there’s a faster way to transmit data than over traditional radio.
The clip was filmed at the European Space Agency’s optical ground station in Tenerife, Spain, on Oct. 8 as part of a social media event. Below, you can see a shot of the laser in action, aiming at the sky. More photos are here.
A green laser shines out into space at an October 2014 social media event at the European Space Agency’s optical ground station in Spain. Credit: Daniel Lopez/IAC
