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
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
Not to be outdone by the feisty Opportunity Rover, the HiRISE camera on NASA’s Mars Reconnaissance Orbiter (MRO) turned in its homework this evening with a fine image of comet C/2013 Siding Spring taken during closest approach on October 19.
The highest-resolution images were acquired by HiRISE at the minimum distance of 85,750 miles (138,000 km). The image has a scale of 453 feet (138-m) per pixel.
The top set of photos uses the full dynamic range of the camera to accurately depict brightness and detail in the nuclear region and inner coma. Prior to its arrival near Mars astronomers estimated the nucleus or comet’s core diameter at around 0.6 mile (1 km). Based on these images, where the brightest feature is only 2-3 pixels across, its true size is shy of 1/3 mile or 0.5 km. The bottom photos overexpose the comet’s innards but reveal an extended coma and the beginning of a tail extending to the right.
Annotated photo of Comet Siding Spring taken by the Opportunity Rover on October 19 when near closest approach. Credit: NASA/JPL-Caltech/Cornell Univ./ASU/TAMU
To photograph a fast-moving target from orbit, engineers at Lockheed-Martin in Denver precisely pointed and slewed the spacecraft based on comet position calculations by engineers at JPL. To make sure they knew exactly where the comet was, the team photographed the comet 12 days in advance when it was barely bright enough to register above the detector’s noise level. To their surprise, it was not exactly where orbital calculations had predicted it to be. Using the new positions, MRO succeeded in locking onto the comet during the flyby. Without this “double check” its cameras may have missed seeing Siding Spring altogether!
Meanwhile, the Jet Propulsion Lab has released an annotated image showing the stars around the comet in the photo taken by NASA’s Opportunity Rover during closest approach. From Mars’ perspective the comet passed near Alpha Ceti in the constellation Cetus, but here on Earth we see it in southern Ophiuchus not far from Sagittarius.
Comet Siding Spring continues on its way today past the planet Mars in this photo taken on October 20. Copyright: Rolando Ligustri
“It’s excitingly fortunate that this comet came so close to Mars to give us a chance to study it with the instruments we’re using to study Mars,” said Opportunity science team member Mark Lemmon of Texas A&M University, who coordinated the camera pointing. “The views from Mars rovers, in particular, give us a human perspective, because they are about as sensitive to light as our eyes would be.”
After seeing photos from both Earth and Mars I swear I’m that close to picturing this comet in 3D in my mind’s eye. NASA engineers and scientists deserve a huge thanks for their amazing and successful effort to turn rovers and spacecraft, intended for other purposes, into comet observatories in a pinch and then deliver results within 24 hours. Nice work!
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.
It looks like NASA’s hard-working Opportunity Rover nabbed our very first pictures of a comet seen from another world! A study of raw images taken by the rover turned up a very promising fuzzy object. Only three night sky pictures were posted today, but two clearly show a fuzzy spot near the center of the field. Stars show as points of light and there are what appear to be a smattering of cosmic ray hits, but in the photo above, the brightest object is slightly elongated (trailed during the exposure?) and cometary in appearance.
Here’s another photo:
A second picture from Opportunity possibly showing the comet. Click for original. Credit: NASA/JPL-Caltech
Looking back over earlier photos of the sky taken on Sol 3212 show only stars and no fuzzy blobs. The pictures were taken around 4:13 a.m. local time with the Sun 25 degrees below the horizon. Opportunity can photograph diffuse objects as dim as the Andromeda Galaxy at magnitude +3.5 and stars down to magnitude +6 or +7. That’s similar to what we see on Earth on very dark night. Since the comet glowed far brighter at around magnitude -5 by some estimates, it would be a relatively easy catch for the rover panoramic camera.
Curiousity Navcam photo of the sky on October 19, 2014, shows the silhouetted rim of Gale Crater and lots of noise. Credit: NASA/JPL-Caltech
NASA has also posted images taken by the Curiosity Rover but for the life of me I can’t find any sign of the Comet Siding Spring. Maybe it’ll pop out after the noise is removed. We’ll keep you posted.
Another Curiosity photo of the sky. If you look closely you’ll see stars among the noise. Click for original Credit: NASA/JPL-Caltech
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.
Comet C/2013 A1 Siding Spring passed between the Small Magellanic Cloud (left) and the rich globular cluster NGC 130 on August 29, 2014. Credit: Rolando Ligustri
We present here a compendium of Universe Today articles on comet Siding Spring. Altogether 18 Universe Today stories and counting have represented our on-going coverage of a once in a lifetime event. The articles beginning in February 2013, just days after its discovery, lead to the comet’s penultimate event – the flyby of Mars, October 19, 2014. While comet Siding Spring will reach perihelion just 6 days later, October 25, 2014, it will hardly have sensed the true power and impact that our Sun can have on a comet.
Siding Spring’s Oort Cloud cousin, Comet ISON in November 2013 encountered the Sun at a mere 1.86 million km. The intensity of the Sun’s glare was 12,600 times greater than what Siding Spring will experience in a few days. Comet ISON did not survive its passage around the Sun but Comet Siding Spring will soon turn back and begin a very long journey to its place of origin, the Oort Cloud far beyond Pluto.
An animation of comet Siding Springs passage through the inner Solar System. The scale size of its place of origin would dwarf the orbits of the Solar System to little more than a small dot. (Illustration Credit: Near-Earth Object (NEO) office, NASA/JPL)
The closest approach for comet Siding Spring with the Sun – perihelion is at a distance of 1.39875 Astronomical Units (1 AU being the distance between the Earth and Sun), still 209 million km (130 million miles). The exact period of the comet is not exactly known but it is measured in millions of years. In my childhood astronomy book, it stated that comet Halley, when it is at its furthest distance from the Sun, is moving no faster than a galloping horse. This has also been all that comet Siding Spring could muster for millions of years – the slightest of movement in the direction of the Sun.
It is only in the last 3 years, out all the millions spent on its journey, that it has felt the heat of the Sun and been in proximity to the planetary bodies of our Solar System. This is story of all long period comets. A video camera on Siding Spring would have recorded the emergence and evolution of one primate out of several, one that left the trees to stand on two legs, whose brain grew in size and complexity and has achieved all the technological wonders (and horrors) we know of today.
Now with its close encounter with Mars, the planet’s gravity will bend the trajectory of the comet and reduce its orbital period to approximately one million years. No one will be waiting up late for its next return to the inner Solar System.
It is also unknown what force in the depths of the Oort cloud nudged the comet into its encounter with Mars and the Sun. Like the millions of other Oort cloud objects, Siding Spring has spent its existence – 4.5 Billion years, in the darkness of deep space, with its parent star, the Sun, nothing more than a point of light, the brightest star in its sky. The gravitational force that nudged it may have been a passing star, another cometary body or possibly a larger trans-Neptunian object the size of Pluto and even as large as Mars or the Earth.
The forces of nature on Earth cause a constant turning over geological features. Our oceans and atmosphere are constantly recycling water and gases. The comets that we receive from the Oort Cloud are objects as old as our Solar System. Yet it is the close encounter with Mars that has raised the specter of an otherwise small ordinary comet. All these comets from deep space are fascinating gems nearly unaltered for 1/3rd of the time span of the known Universe.
An image of a May 9, 2014 coronal mass ejection from the Sun using data from both the Interface Region Imaging Spectrograph (IRIS) spacecraft and the Solar Dynamics Observatory. Credit: NASA, Lockheed Martin Solar & Astrophysics Laboratory
My, the Sun is a violent place. I mean, we knew that already, but there’s even more evidence for that using new data from a brand-new NASA spacecraft. There’s talk now about tornadoes and jets and even “bombs” swirling amid our Sun’s gassy environment.
A huge set of results from NASA’s Interface Region Imaging Spectrograph (IRIS) spacecraft reveals the true nature of a mysterious transition zone between Sun’s surface and the corona, or atmosphere. Besides the pretty fireworks and videos, these phenomena are telling scientists more about how the Sun moves energy from the center to the outskirts. And, it could tell us more about how stars work in general.
The results are published in five papers yesterday (Oct. 15) in Science magazine. Below, a brief glimpse of what each of these papers revealed about our closest star.
Bombs
This is a heck of a lot of energy packed in here. Raging at temperatures of 200,000 degrees Fahrenheit (111,093 degrees Celsius) are heat “pockets” — also called “bombs” because they release energy quickly. They were found lower in the atmosphere than expected. The paper is here (led by Hardi Peter of the Max Planck Institute for Solar System Research in Gottingen, Germany.)
Tornadoes
It’s a twist! You can see some structures in the chromosphere, just above the Sun’s surface, showing gas spinning like a tornado. They spin around as fast as 12 miles (19 kilometers) a second, which is considered slow-moving on the Sun. The paper is here (led by Bart De Pontieu, the IRIS science lead at Lockheed Martin in California).
High-speed jets
Artist’s impression of the solar wind from the sun (left) interacting with Earth’s magnetosphere (right). Credit: NASA
How does the solar wind — that constant stream of charged particles that sometimes cause aurora on Earth — come to be? IRIS spotted high-speed jets of material moving faster than ever observed, 90 miles (145 kilometers) a second. Since these jets are emerging in spots where the magnetic field is weaker (called coronal holes), scientists suspect this could be a source of the solar wind since the particles are thought to originate from there. The paper is here (led by Hui Tian at the Harvard-Smithsonian Center for Astrophysics in Massachusetts.)
Nanoflares
A solar filament erupts with a coronal mass ejection in this image captured by NASA’s Solar Dynamics Observatory in August 2012. Credit: NASA’s GSFC, SDO AIA Team
Those solar flares the Sun throws off happen when magnetic field lines cross and then snap back into place, flinging particles into space. Nanoflares could do the same thing to heat up the corona, and that’s something else that IRIS is examining. The paper is here (led by Paola Testa, at the Harvard-Smithsonian Center for Astrophysics.)
Structures and more
And here is the transition region in glorious high-definition. Improving on data from the Skylab space station in the 1970s (bottom of video), you can see all sorts of mini-structures on the Sun. The more we learn about these 2,000-mile (3,220-km) objects, the better we’ll understand how heating moves through the Sun. The paper is here (led by Viggo Hansteen, at the University of Oslo in Norway.)
NOAA's GOES-East satellite captured this image of Hurricane Gonzalo off the U.S. East Coast on Oct. 16 at 13:07 UTC (9:07 a.m. EDT). Gonzalo is classified as Category 4 storm. Credit: NASA/NOAA GOES Project
Hurricane Gonzalo, the first major Atlantic Ocean basin hurricane in three years, has strengthened to a dangerous Category 4 storm, threatening Bermuda and forcing a postponement of the upcoming launch of the Orbital Sciences Antares rocket to the space station from the Virginia shore to no earlier than Oct. 27.
A hurricane warning is in effect for the entire island of Bermuda.
NASA and Orbital Sciences had no choice but to delay the Antares blastoff from Oct. 24 to no earlier than Oct. 27 because Bermuda is home to an “essential tracking site” that must be operational to ensure public safety in case of a launch emergency situation.
Antares had been slated for an early evening liftoff with the Cygnus cargo carrier on the Orb-3 mission to the International Space Station (ISS).
NASA and Orbital issued the following statement:
“Due to the impending arrival of Hurricane Gonzalo on the island of Bermuda, where an essential tracking site used to ensure public safety during Antares launches is located, the previously announced “no earlier than” (NET) launch date of October 24 for the Orb-3 CRS mission to the International Space Station for NASA is no longer feasible.”
Orbital Sciences Corporation Antares rocket and Cygnus spacecraft prior to blast off on July 13 2014 from Launch Pad 0A at NASA Wallops Flight Facility , VA, on the Orb-2 mission bound for the International Space Station. Credit: Ken Kremer – kenkremer.com
The powerful Gonzalo is currently expected to make a direct hit on Bermuda on Friday afternoon, Oct. 17. It’s packing devastating maximum sustained winds exceeding 145 mph (225 kph).
NASA and NOAA satellites including the Terra, Aqua and GOES-East satellites are providing continuous coverage of Hurricane Gonzalo as it moves toward Bermuda, according to a NASA update today.
The ISS-RapidScat payload tracking ocean winds, that was just attached to the exterior of the ISS, is also designed to help with hurricane monitoring and forecasting.
Tropical storm force winds and 20 to 30 foot wave heights are expected to impact Bermuda throughout Friday and continue through Saturday and into Sunday.
“The National Hurricane Center expects hurricane-force winds, and rainfall totals of 3 to 6 inches in Bermuda. A storm surge with coastal flooding can be expected in Bermuda, with large and destructive waves along the coast. In addition, life-threatening surf and riptide conditions are likely in the Virgin Islands, Puerto Rico, Dominican Republic, Bahamas. Those dangerous conditions are expected along the U.S. East Coast and Bermuda today, Oct. 16,” according to NASA.
On Oct. 15 at 15:30 UTC (11:30 a.m. EDT) NASA’s Terra satellite captured this image of Hurricane Gonzalo in the Atlantic Ocean. Credit: NASA Goddard MODIS Rapid Response Team
After the hurricane passes, a team will be sent to assess the impact of the storm on Bermuda and the tracking station. Further delays are possible if Bermuda’s essential infrastructure systems are damaged, such as power, transportation and communications.
The Antares/Cygnus rocket and cargo ship launch from the Mid-Atlantic Regional Spaceport at NASA’s Wallops Flight Facility along the eastrn shore of Virginia.
Liftoff is currently target for October 27 at 6:44 p.m. (EDT). The rendezvous and berthing of Cygnus with the ISS remains on November 2, with grapple of the spacecraft by the station’s robotic arm at approximately 4:58 a.m. (EST), according to a NASA update.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Two potential targets for the New Horizons mission emerge in these Hubble Space Telescope multiple-exposure images. Both are about four billion miles (6.4 billion kilometers) away. NASA, ESA, SwRI, JHU/APL, and the New Horizons KBO Search Team
Where could New Horizons visit after it flies by Pluto next year? NASA’s Hubble Space Telescope is on the case. In a program that pushed the limits of the 24-year-old observatory, Hubble found three potential Kuiper Belt Objects for the spacecraft to visit.
The wrinkle is there is no money approved yet for New Horizons to do an extended mission yet, but team members (including Alex Parker from the Southwest Research Institute, who is quoted from Twitter below) are celebrating the milestone. To them, the most promising target (PT1) is the one on the left of the images you see above. Read more about it below the jump.
The Kuiper Belt is a zone of icy objects about four billion miles (6.4 billion kilometers) from the Sun, considered to be leftovers of the building blocks that put together the Solar System billions of years ago. It’s an area that Pluto itself drifts through from time to time on its elliptical orbit around the Sun. Roughly 1,000 objects there have been cataloged, although many more are believed to exist.
The team used Hubble from June 16 to 26 in a test program to look at 20 sky zones for evidence of KBOs, finding two that had never been spotted before by ground-based telescopes. More searching between July and September revealed one object that is “definitely reachable”, NASA stated, and two others that require more scrutiny.
We estimate that PT1 is several 10s of kilometers across. Here’s what that looks like next to Cape Cod and #Comet67P: pic.twitter.com/IHUx6uymO7
Here is where PT1 lies in relation to the rest of the solar system. The yellow path is New Horizons’ trajectory. pic.twitter.com/4aQDEj8oPZ — Alex Parker (@Alex_Parker) October 15, 2014
Here is a gif of the Hubble Space Telescope discovery images of our New Horizons-targetable Kuiper Belt Object PT1. http://t.co/ifw8I4a8Wz
An important and sobering note: even though New Horizons can reach this Kuiper Belt Object, there is no guarantee of an extended mission. — Alex Parker (@Alex_Parker) October 15, 2014
Each of the three candidates would take a while to reach, as they are all about one billion miles (1.6 billion km) beyond Pluto. They’re also tiny, with two estimated at 34 miles (55 kilometers) across and the third at 15 miles (25 kilometers). This makes them 10 times bigger than the average comet, but only 1-2% the size of small Pluto.
“This was a needle-in-haystack search for the New Horizons team because the elusive KBOs are extremely small, faint, and difficult to pick out against a myriad background of stars in the constellation Sagittarius, which is in the present direction of Pluto,” NASA wrote in a press release.
New Horizons’ team plans to ask for the extended mission in late 2016. Meanwhile, the spacecraft (which has been flying ever outwards since 2006) will finally zoom past its main target of Pluto in July 2015.
