Universe Today

November 12, 2014December 23, 2015 by Elizabeth Howell

Uranus Bland? Nope, It’s A Stormy Planet With Interesting Insides

A composite image of Uranus in two infrared bands, showing the planet and its ring system. Picture taken by the Keck II telescope and released in 2007. Credit: W. M. Keck Observatory (Marcos van Dam)

Sometimes first impressions are poor ones. When the Voyager 2 spacecraft whizzed by Uranus in 1986, the close-up view of the gas giant revealed what appeared to a be a relatively featureless ball. By that point, scientists were used to seeing bright colors and bands on Jupiter and Saturn. Uranus wasn’t quite deemed uninteresting, but the lack of activity was something that was usually remarked upon when describing the planet.

Fast-forward 28 years and we are learning that Uranus is a more complex world than imagined at the time. Two new studies, discussed at an American Astronomical Society meeting today, show that Uranus is a stormy place and also that the images from Voyager 2 had more interesting information than previously believed.

Showing the value of going over old data, University of Arizona astronomer Erich Karkoschka reprocessed old images of Voyager 2 data — including stacking 1,600 pictures on top of each other.

He found elements of Uranus’ atmosphere that reveals the southern hemisphere moves differently than other regions in fellow gas giants. Since only the top 1% of the atmosphere is easily observable from orbit, scientists try to make inferences about the 99% that lie underneath by looking at how the upper atmosphere behaves.

“Some of these features probably are convective clouds caused by updraft and condensation. Some of the brighter features look like clouds that extend over hundreds of kilometers,” he stated in a press release.

“The unusual rotation of high southern latitudes of Uranus is probably due to an unusual feature in the interior of Uranus,” he added. “While the nature of the feature and its interaction with the atmosphere are not yet known, the fact that I found this unusual rotation offers new possibilities to learn about the interior of a giant planet.”

It’s difficult to get more information about the inner atmosphere without sending down a probe, but other methods of getting a bit of information include using radio (which shows magnetic field rotation) or gravitational fields. The university stated that Karkoschka’s work could help improve models of Uranus’ interior.

So that was Uranus three decades ago. What about today? Turns out that storms are popping up on Uranus that are so large that for the first time, amateur astronomers can track them from Earth. A separate study on Uranus shows the planet is “incredibly active”, and what’s more, it took place at an unexpected time.

Summer happened in 2007 when the Sun shone on its equator, which should have produced more heat and stormy weather at the time. (Uranus has no internal heat source, so the Sun is believed to be the primary driver of energy on the planet.) However, a team led by Imke de Pater, chair of astronomy at the University of California, Berkeley, spotted eight big storms in the northern hemisphere while looking at the planet with the Keck Telescope on Aug. 5 and 6.

Infrared images of Uranus showing storms at 1.6 and 2.2 microns obtained Aug. 6, 2014 by the 10-meter Keck telescope. Credit: Imke de Pater (UC Berkeley) & Keck Observatory images.

Keck’s eye revealed a big, bright storm that represented 30% of light reflected by the planet at a wavelength of 2.2 microns, which provides information about clouds below the tropopause. Amateurs, meanwhile, spotted a storm of a different sort. Between September and October, several observations were reported of a storm at 1.6 microns, deeper in the atmosphere.

“The colors and morphology of this [latter] cloud complex suggests that the storm may be tied to a vortex in the deeper atmosphere similar to two large cloud complexes seen during the equinox,” stated Larry Sromovsky, a planetary scientist at the University of Wisconsin, Madison.

What is causing the storms now is still unknown, but the team continues to watch the Uranian weather to see what will happen next. Results from both studies were presented at the Division for Planetary Sciences meeting of the American Astronomical Society in Tucson, Arizona today. Plans for publication and whether the research was peer-reviewed were not disclosed in press releases concerning the findings.

November 12, 2014December 23, 2015 by Bob King

Philae’s First Photos; Update on its Troubled Landing

Image from the Philae lander as it approached the surface. The dust-covered boulder at upper right is about 5 meters (16.4 feet) across. The dust might have originated through vaporization of ice on the boulder itself or deposited there by dust settling from jets elsewhere. Credit: ESA

First photo released of Comet 67P/C-G taken by Philae during its descent. The view is just 1.8 miles above the comet. Credit: ESA

Hey, we’re getting closer! This photo was taken by Philae’s ROLIS instrument just 1.8 miles (3 km) above the surface of 67P/Churyumov-Gerasimenko at 8:38 a.m. (CST) today. The ROLIS instrument is a down-looking imager that acquires images during the descent and doubles as a multi-wavelength close-up camera after the landing. The aim of the ROLIS experiment is to study the texture and microstructure of the comet’s surface. ROLIS (ROsetta Lander Imaging System) is a descent and close-up camera on the Philae lander.

I know, I know. You got a fever for more comet images the way Christopher Walken on Saturday Night Live couldn’t get enough cowbell.

Just to give you a flavor for the rugged landscape Philae was headed toward earlier today, this photo was taken by Rosetta at an altitude of 4.8 miles (7.7 km) from the comet's surface. Credit: ESA — Just for a little flavor of the rugged landscape Philae was headed toward earlier today, this photo was taken recently by Rosetta 4.8 miles (7.7 km) from the comet’s surface. Credit: ESA

Key scientists in a media briefing this afternoon highlighted the good news and the bad news about the landing. We reported earlier that both the harpoons and top thrusters failed to fire and anchor the lander to the comet. Yet land it did – maybe more than once! A close study of the data returned seems to indicate that Philae, without its anchors, may have touched the surface and then lifted off again, turning itself from the residual angular momentum left over after its flywheel was shut down. Stephan Ulamec, Philae Landing Manager, got a appreciative laugh from the crowd when he explained it this way: Maybe today we didn’t just land once. We landed twice!”

Stephan Ulamec, Philae Lander Manager. Credit: ESA

Telemetry from the probe has been sporadic. Data streams come in strong and then suddenly cut out only to return later. These fluctuations in the radio link obviously have the scientists concerned and as yet, there’s no explanation for them. Otherwise, Philae landed in splendid fashion almost directly at the center of its planned “error ellipse”.

Instruments on Philae are functioning normally and gathering data as you read this. Ulamec summed up the situation nicely: “It’s complicated to land and also complicated to understand the landing.”

Scientists and mission control will work to hopefully resolve the harpoon and radio link issues. The next live webcast begins tomorrow starting at 7 a.m. (CST). Although nothing definite was said, we may see more images arriving still today, so stop by later.

November 12, 2014December 23, 2015 by Elizabeth Howell

Virgin Galactic Crash Survivor Didn’t Know Re-Entry System Was Turned On Prematurely

NTSB investigators are seen making their initial inspection of debris from the Virgin Galactic SpaceShipTwo. The debris field stresses over a fiver mile range in the Mojave desert. (Credit: Getty Images)

The surviving co-pilot of the Virgin Galactic crash was unaware that SpaceShipTwo’s re-entry system was unlocked prematurely during the flight test, according to an update from the National Transportation Safety Board.

In an interview with investigators, the board said Peter Siebold provided testimony that was consistent with other information gathered so far since the crash. The incident, which killed fellow co-pilot Mike Alsbury when the craft plunged into the Mojave desert, took place Oct. 31.

“The NTSB operations and human performance investigators interviewed the surviving pilot on Friday. According to the pilot, he was unaware that the feather system had been unlocked early by the copilot,” read an update on the board’s website.

“His description of the vehicle motion was consistent with other data sources in the investigation. He stated that he was extracted from the vehicle as a result of the break-up sequence and unbuckled from his seat at some point before the parachute deployed automatically.”

Inset: Pilot Peter Siebold of Scaled Composites. Photo of SpaceShipTwo, SS Enterprise, in flight with its tail section in the feathered position for atmospheric re-entry. (Photo Credits: Scaled Composites)

Accidents are due to a complex set of circumstances, which means the NTSB finding that the re-entry system was deployed prematurely is only a preliminary finding. The investigation into the full circumstances surrounding the crash could take anywhere from months to a year, according to multiple media reports.

Virgin was performing another in a series of high-altitude test flights in preparation for running tourists up to suborbital space early next year. A handful of ticket-holders, who made deposits of up to $250,000 each, have reportedly asked for their money back. The Richard Branson-founded company has not revealed when the first commercial flight is expected to take place.

Meanwhile, Virgin does have another version of SpaceShipTwo already under assembly right now, which is considered 95% structurally complete and 60% assembled, according to NBC News. The prototype could take to the skies before the NTSB investigation is complete, the report added.

November 12, 2014December 23, 2015 by Bob King

Touchdown! Philae Successfully Lands on Rosetta’s Comet

Excitement ripples through the ESA control room with the news that Philae successfully landed on the comet this morning. Credit: ESA

We did it! We’re on the comet! At about 9:37 a.m. (CST) Philae touched down on Rosetta’s Comet. After traveling more than 315 million miles (508 million km) the lander’s signal arrived 28 minutes later with the fabulous news. Telemetry is trickling in and the lander’s in great health, but one small concern has arisen. We’ve just learned that the harpoons used to anchor Philae failed to fire. Mission control is considering whether to refire them to make sure the craft is stable.

Philae postcard. Hey, it made it - a huge congratulations to ESA. Credit: ESA — Philae is now at work on the comet after successfully harpooning itself to the surface. A huge congratulations to ESA! Credit: ESA

One might think that as long as the craft is sitting still on the comet, that will do. Well, maybe. Until it’s anchored, activity from nearby jets or even vaporizing ice beneath it could flip it over. After all, Philae only weighs a gram in 67P/C-G’s gravity field. The harpoons also house the instrument that measures surface density. Presumably, without them we won’t get that data.

ESA's version of a Swiss Army knife, Philae will now probe the comet on many levels. Credit: ESA — ESA’s version of a Swiss Army knife, Philae will now probe the comet on many levels. Credit: ESA

Now that Philae has reached its target, science will begin in earnest. Here’s an illustration that describes each of the probe’s instruments. Be sure to click to enlarge.

November 12, 2014December 23, 2015 by Elizabeth Howell

Jupiter’s Great Red Spot Gets Its Color From Sunlight, Study Suggests

Reprocessed view by Bjorn Jonsson of the Great Red Spot taken by Voyager 1 in 1979 reveals an incredible wealth of detail.

If it weren’t for the Sun, Jupiter’s Great Red Spot would be a much blander feature on the gas giant, a new study reveals. This stands apart from what most scientists think about why for why the spot looks so colorful: that there are features in the clouds that give it its distinctive shade.

The new data comes from observations with the Cassini spacecraft, combined with experiments in the lab. They conclude that the Red Spot’s immense height, combined with sunlight breaking apart the atmosphere there into certain chemicals, make the feature that red that is visible even in small telescopes.

“Our models suggest most of the Great Red Spot is actually pretty bland in color, beneath the upper cloud layer of reddish material,” said Kevin Baines, a Cassini team scientist based at NASA’s Jet Propulsion Laboratory in California, in a statement. “Under the reddish ‘sunburn’ the clouds are probably whitish or grayish.”

Jupiter’s Great Red Spot is a cyclone larger than two Earths. (photomontage ©Michael Carroll)

The lab experiments combined ammonia and acetylene gases (atmospheric components from Jupiter) with ultraviolet light (simulating what the Sun produces), which created a ruddy substance that matched observations made with the Cassini spacecraft back in 2000. They also tried breaking apart ammonium hydrosulfide, a common element in Jupiter’s high clouds, but the color produced was actually a bright green.

The Great Red Spot is a storm that has been raging on Jupiter since at least when telescopes were first used in the 1600s. Over the past few decades, its size has shrunk considerably –it’s now half of what historical measurements showed — but it is still much larger than Earth. Scientists are hoping the forthcoming Juno mission, which will arrive at Jupiter at 2016, will help learn more about what is going on.

Results were presented at the Division for Planetary Science of the American Astronomical Society’s annual meeting this week in Tucson, Arizona. A press release did not disclose publication plans or if the research is peer-reviewed.

Source: NASA

November 12, 2014December 23, 2015 by Bob King

We Land on a Comet Today! Updates on Philae’s Progress

Just released "farewell photo" taken by the Philae lander as it departed Rosetta around 2:30 a.m. (CST) today. It shows the one of the solar arrays. Credit: ESA/Rosetta/Philae/CIVA

Anticipation is intense as the Philae lander free-falls to the surface of Comet Churyumov-Gerasimenko this morning. The final “Go” for separation from the Rosetta spacecraft was given around 2:30 a.m.; Philae’s now well on its way to Agilkia, the target landing site atop the 67P/C-G’s largerEverything is running smoothly except for one potential problem. During checks on the lander’s health, it was discovered that the active descent system, which provides a thrust to avoid rebound at the moment of touchdown, can’t be activated.

Artist impression of Philae separating from Rosetta earlier this morning. The lander is now free-falling to the comet under the influence of its gravity. Credit: ESA

At touchdown, as Philae anchors itself to the comet with harpoons and ice screws on each of its legs, the thruster on top of the lander is supposed to push it down to counteract the force of the harpoon firing in the opposite direction.

Klim Churyumov (left) Svetlana Gerasimenko are both at ESA today during the historic landing on the comet they discovered on September 20, 1969. Credit: ESA TV

“The cold gas thruster on top of the lander does not appear to be working so we will have to rely fully on the harpoons at touchdown,”says Stephan Ulamec, Philae Lander Manager at the DLR German Aerospace Center.

The Philae that could! The lander photographed during its descent by Rosetta. Credit: ESA/Rosetta/MPS for Rosetta Team/

Philae is on target to land on the comet around 9:37 a.m. CST (15:37 UT). Confirmation of touchdown will take about 28 minutes as the signal, traveling at the speed of light, works its way back on Earth. As Philae floats down to the comet it not only has to deal with the 67P/C-G’s gravity but also the cloud of dust and ice grains escaping from the surface. Check back for regular updates and photos!

Tense control room during the Philae landing confirmation. Credit: ESA — Tense control room during the Philae landing confirmation Time: 9:48 a.m. CST. Credit: ESA

November 12, 2014December 23, 2015 by Bob King

Better than Bieber, Rosetta’s Comet Sings Strange, Seductive Song

Magnetic field lines bound up in the sun’s wind pile up and drape around a comet’s nucleus to shape the blue ion tail. Notice the oppositely-directed fields on the comet’s backside. The top set points away from the comet; the bottom set toward. In strong wind gusts, the two can be squeezed together and reconnect, releasing energy that snaps off a comet’s tail. Credit: Tufts University

Tune in to the song of Comet Churyumov-Gerasimenko

Scientists can’t figure exactly why yet, but Comet 67P/Churyumov-Gerasimenko has been singing since at least August. Listen to the video – what do you think? I hear a patter that sounds like frogs, purring and ping-pong balls. The song is being sung at a frequency of 40-50 millihertz, much lower than the 20 hertz – 20 kilohertz range of human hearing. Rosetta’s magnetometer experiment first clearly picked up the sounds in August, when the spacecraft drew to within 62 miles (100 km) of the comet. To make them audible Rosetta scientists increased their pitch 10,000 times.

The sounds are thought to be oscillations in the magnetic field around the comet. They were picked up by the Rosetta Plasma Consortium, a suite of five instruments on the spacecraft devoted to observing interactions between the solar plasma and the comet’s tenuous coma as well as the physical properties of the nucleus. A far cry from the stuff you donate at the local plasma center, plasma in physics is an ionized gas. Ionized means the atoms in the gas have lost or gained an electron through heating or collisions to become positively or negatively charged ions. Common forms of plasma include the electric glow of neon signs, lightning and of course the Sun itself.

Having lost their neutrality, electric and magnetic fields can now affect the motion of particles in the plasma. Likewise, moving electrified particles affect the very magnetic field controlling them.

Scientists think that neutral gas particles from vaporizing ice shot into the coma become ionized under the action of ultraviolet light from the Sun. While the exact mechanism that creates the curious oscillations is still unknown, it might have something to do with the electrified atoms or ions interacting with the magnetic fields bundled with the Sun’s everyday outpouring of plasma called the solar wind. It’s long been known that a comet’s electrified or ionized gases present an obstacle to the solar wind, causing it to drape around the nucleus and shape the streamlined blue-tinted ion or gas tail.

“This is exciting because it is completely new to us. We did not expect this, and we are still working to understand the physics of what is happening,” said Karl-Heinz Glassmeier, head of Space Physics and Space Sensorics at the Technical University of Braunschweig, Germany.

While 67P C-G’s song probably won’t make the Top 40, we might listen to it just as we would any other piece of music to learn what message is being communicated.

November 11, 2014December 23, 2015 by Tim Reyes

Philae Ready to Take Flying Leap to Historic Comet Landing (Coverage Information)

After a ten year journey that began with the launch from the jungles of French Guyana, landing Philae is not the end of mission, it is the beginning of a new phase. A successful landing is not guaranteed but the ESA Rosetta team is now ready to release Philae on its one way journey. (Photo Credits: ESA/NASA, Illustration: J.Schmidt)

We are now in the final hours before Rosetta’s Philae lander is released to attempt a first-ever landing on a comet. At 9:03 GMT (1:03 AM PST) on Wednesday, November 12, 2014, Philae will be released and directed towards the surface of comet 67P/Churyumov–Gerasimenko. 7 hours later, the lander will touch down.

Below you’ll find a timeline of events, info on how to watch the landing, and an overview of how the landing will (hopefully) work.

In human affairs, we build contingencies for missteps, failures. With spacecraft, engineers try to eliminate all single point failures and likewise have contingency plans. The landing of a spacecraft, be it on Mars, Earth, or the Moon, always involves unavoidable single point failures and points of no return, and with comet 67P/Churyumov–Gerasimenko, Rosetta’s Philae lander is no exception.

Rosetta’s and Philae’s software and hardware must work near flawlessly to give Philae the best chance possible of landing safely. And even with flawless execution, it all depends on Philae’s intercepting a good landing spot on the surface. Philae’s trajectory is ballistic on this one way trip to a comet’s surface. It’s like a 1 mile per hour bullet. Once fired, it’s on its own, and for Philae, its trajectory could lead to a pristine flat step or it could be crevasse, ledge, or sharp rock.

Live European Space Agency Coverage also Main Page Live Feed

Watch ESA’s live feed:

The accuracy of the landing is critical but it has left a 1 square kilometer of uncertainty. For this reason, engineers and scientists had to survey the whole surface for the most mild features. Comet 67P has few areas that are not extreme in one way or another. Site J, now called Agilkia, is one such site.

When first announced in late September, the time of release was 08:35 GMT (12:35 AM PST). Now the time is 9:03 GMT. The engineers and computer scientists have had six weeks to further refine their trajectory. It’s a complicated calculation that has required running the computer simulation of the descent backwards. Backwards because they can set a landing time then run Philae backwards to the moment of release. The solution is not just one but many, thousands or millions if you want to look in such detail. With each release point, the engineers had to determine how, or if, Rosetta could be navigated to that coordinate point in space and time.

Arrival time of the radio signal with landing status: 16:30 GMT

Rosetta/Philae at 500 million km [320 million miles], 28.5 minutes light time

Arrival of First Images: 06:00 GMT, November 13, 2014

The gravity field of the comet is so weak, it is primarily the initial velocity from Rosetta that delivers Philae to the surface. But the gravity is there and because of the chaotic shape and unknown (as yet) mass distribution inside, the gravity will make Philae move like a major league knuckleball wobbling to the plate and a batter. Furthermore, the comet during the seven hour trip will make half a rotation. The landing site will not be in site when Philae is released.

And as Philae is on final approach, it will use a small rocket not to slow down but rather thrust it at the comet, landing harpoons will be fired, foot screws will try to burrow into the comet, and everyone on Earth will wait several minutes for a message to be relayed from Philae to Rosetta to the Deep Space Network (DSN) antennas on Earth. Philae will be on its own as soon as it leaves Rosetta and its fate is a few hours away.

Why travel to a comet? Comets represent primordial material leftover from the formation of the solar system. Because cometary bodies were formed and remained at a distance from the heat of the sun, the materials have remained nearly unchanged since formation, ~4.5 billion years ago. By looking at Rosetta’s comet, 67P/Churyumov–Gerasimenko, scientists will gain the best yet measurements of a comet’s chemical makeup, its internal structure created during formation, and the dynamics of the comet as it approaches the warmth of the Sun. Theories propose that comets impacting on Earth delivered most of the water of our oceans. If correct, then we are not just made of star-stuff, as Carl Sagan proclaimed, we are made of comet stuff, too. Comets may also have delivered the raw organic materials needed to start the formation of life on Earth.

Besides the ESA live feeds, one can take a peek at NASA’s Deep Space Network (DSN) at work to see which telescopes are communicating with Rosetta. JPL’s webcast can watched below:

Broadcast live streaming video on Ustream

Past Universe Today Articles on the Rosetta Mission:

A Comet’s Tale – Rosetta’s Philae, Five Days from Touchdown
Stinky! Rosetta’s Comet Smells Like Rotten Eggs And Ammonia
Why Watch ESA Rosetta’s Movie ‘Ambition’? Because We Want to Know What is Possible
Rosetta’s Philae Lander: A Swiss Army Knife of Scientific Instruments
ESA’s Rosetta Mission sets November 12th as the Landing Date for Philae
Creepy Comet Looms In The Background Of Newest Philae Spacecraft Selfie
How Do You Land on a Comet? Very Carefully.
How Rosetta Will Send Philae Lander To Comet’s Surface (Plus, Landing Site Contest!)
Spider-Like Spacecraft Aims To Touch A Comet Next Year After Rosetta Reactivates
Rosetta’s Comet Springs Spectacular Leaks As It Gets Closer To The Sun
How Dust Lightens Up The ‘Dark Side’ Of Rosetta’s Comet
It’s Alive! Rosetta’s Comet Flares As It Approaches The Sun

References:

Why visit a comet, University of Leicester, Planetary Scientist explains

November 11, 2014December 23, 2015 by David Dickinson

Midway Between Storms: Our Guide to the 2014 Leonid Meteors

If there’s one meteor shower that has the potential to bring on a storm of epic proportions, it’s the Leonids. Peaking once every 33 years, these fast movers hail from the Comet 55P Temple-Tuttle, and radiate from the Sickle, or backwards “question mark” asterism in the constellation Leo. And although 2014 is an “off year” in terms of storm prospects, it’s always worth taking heed these chilly November mornings as we await the lion’s roar once again.

The prospects: 2014 sees the expected peak of the Leonids arriving around 22:00 Universal Time (UT) which is 5:00 PM EST. Locally speaking, a majority of meteor showers tend to peak in the early AM hours past midnight, as the observer’s location turns forward facing into the oncoming meteor stream. Think of driving in an early November snowstorm, with the car being the Earth and the flakes of snow as the oncoming meteors. And if you’ve (been fortunate enough?) to have never seen snow, remember that it’s the front windshield of the car going down the highway that catches all of the bugs!

This all means that in 2014, the Asian Far East will have an optimal viewing situation for the Leonids, though observers worldwide should still be vigilant. Of course, meteor showers never read online prognostications such as these, and often tend to arrive early or late. The Leonids also have a broad range of activity spanning November 6^th through November 30^th.

The November path of the radiant of the 2014 Leonids. Credit: Starry Night Education Software.

The predicted ideal Zenithal Hourly Rate for 2014 stands at about 15, which is well above the typical background sporadic rate, but lower than most years. Expect the actual sky position of the radiant and light pollution to lower this hourly number significantly. And speaking of light pollution, the Moon is a 21% illuminated waning crescent on the morning of November 17^th, rising at around 2:00 AM local in the adjacent constellation of Virgo.

The Leonids can, once every 33 years, produce a storm of magnificent proportions. The history of Leonid observation may even extend back as far as 902 A.D., which was recorded in Arab annals as the “Year of the Stars.”

But it was the morning of November 13^th, 1833 that really gained notoriety for the Leonids, and really kicked the study of meteor showers into high gear.

The night was clear over the U.S. Eastern Seaboard, and frightened townsfolk were awakened to moving shadows on bedroom walls. Fire was the first thing on most people’s minds, but they were instead confronted with a stunning and terrifying sight: a sky seeming to rain stars in every direction. Churches quickly filled up, as folks reckoned the Day of Judgment had come. The 1833 Leonid storm actually made later historical lists as one of the 100 great events in the United States for the 19^th century. The storm has also been cited as single-handedly contributing to the religious fundamentalist revivals of the 1830s. Poet Walt Whitman witnessed the 1833 storm, and the song The Stars Fell on Alabama by Frank Perkins was inspired by the event as well.

Live in Alabama? Then you may well possess a license plate that commemorates the 1833 Leonid Storm. Wikimedia Commons image in the Public Domain.

But not all were fearful. Astronomer Denison Olmsted was inspired to study the radiants and paths of meteor streams after the 1833 storm, and founded modern meteor science. The Leonids continued to produce storms at 33 year intervals, and there are still many observers that recall the spectacle that the Leonids produced over the southwestern U.S. back 1966, with a zenithal hourly rate topping an estimated 144,000 per hour!

We also have a personal fondness for this shower, as we were fortunate enough to witness the Leonids from the dark desert skies of Kuwait back in 1998. We estimated the shower approached a ZHR of about 900 towards sunrise, as a fireballs seemed to light up the desert once every few seconds.

The situation at 22:00 UT on November 17th, noting the direction of the Earth’s motion with relation to the predicted peak of the 2014 Leonid stream. Created using Stellarium.

The Leonids have subsided in recent years, and have fallen back below enhanced rates since 2002. Here’s the most recent ZHR levels as per the International Meteor Organization:

2009: ZHR=80.

2010: ZHR=32.

2011: ZHR=22.

2012: ZHR=48.

Note: 2013 the shower was, for the most part, washed out by the Full Moon.

But this year is also special for another reason.

Note that the 2014-2015 season marks the approximate halfway mark to an expected Leonid outburst around 2032. Comet 55P Tempel-Tuttle reaches perihelion on May 20^th, 2031, and if activity in the late 1990s was any indication, we expect the Leonids to start picking up again around 2030 onward.

A simulated storm on the morning of November 17th, 2032. Credit: Stellarium. — A simulated Leonid storm on the morning of November 17th, 2032. Credit: Stellarium.

Observing meteors is as simple as laying back and looking up. Be sure to stay warm, and trace the trail of any suspect meteor back to the Sickle to identify it as a Leonid. The Leonid meteors have one of the fastest approach velocities of any meteor stream at 71 kilometres per second, making for quick, fleeting passages in the pre-dawn sky. Brighter bolides may leave lingering smoke trails, and we like to keep a set of binoculars handy to examine these on occasion.

Looking to do some real science? You can document how many meteors you see per hour from your location and send this in to the International Meteor Organization, which tabulates and uses these volunteer counts to characterize a given meteor stream.

Leonids Credit: NASA — The 1997 Leonids as seen from space by the MSX satellite. Credit: NASA/JPL

And taking images of Leonid meteors is as simple as setting your DSLR camera on a tripod and taking long exposure images of the night sky. Be sure to use the widest field of view possible, and aim the camera about 45 degrees away from the radiant to nab meteors in profile. We generally shoot 30 second to 3 minute exposures in series, and don’t be afraid to experiment with manual F-stop/ISO combinations to get the settings just right for the local sky conditions. And be sure to carefully review those shots on the “big screen” afterwards… nearly every meteor we’ve caught in an image has turned up this way.

Don’t miss the 2014 Leonids. Hey, we’re half way to the start of the 2030 “storm years!”

November 11, 2014December 23, 2015 by Elizabeth Howell

Dusty Baby Solar System Gives Clues On How Our Sun And Planets Grew Up

Artist's conception of early planetary formation from gas and dust around a young star. Outbursts from newborn and adolescent stars might drive planetary water beneath the surface of rocky worlds. Credit: NASA/NASA/JPL-Caltech

This isn’t a clone of our Solar System, but it’s close enough. Scientists eagerly scrutinized a young star system called HD 95086 to learn more about how dust belts and giant planets grow up together. This is an important finding for our own neighborhood, where the gas giants of Jupiter, Saturn, Uranus and Neptune are also wedged between dusty areas.

“By looking at other star systems like these, we can piece together how our own Solar System came to be,” stated lead author Kate Su, an associate astronomer at the University of Arizona, Tucson.

The system is about 295 light-years from Earth, and is suspected to have two dust belts: a warmer one (similar to our asteroid belt) and a cooler one (similar to the Kuiper Belt that has icy objects.) The system is host to at least one planet that is five times the mass of Jupiter, and other planets could also be hiding between the dusty lanes. This planet, called HD 95086 b, was imaged by the European Southern Observatory’s Very Large Observatory in 2013.

Planet HD95086 b is shown at lower left in this picture. Astronomers blocked out the light of the star (center) to image the exoplanet. The blue circle represents the equivalent orbit of Neptune in this star system. Credit: ESO/J. Rameau

The next step was a comparison study with another star system called HR 8799, which also has two dusty rings and in this case, at least four planets in between. These planets have also been caught on camera. Comparing the structure of the two systems indicates that HD 95086 may have more planets lurking for astronomers to discover.

“By knowing where the debris is, plus the properties of the known planet in the system, we can get an idea of what other kinds of planets can be there,” stated Sarah Morrison, a co-author of the paper and a PhD student at the University of Arizona. “We know that we should be looking for multiple planets instead of a single giant planet.”

The researchers presented their work at the Division for Planetary Science Meeting of the American Astronomical Society in Tucson, Arizona. A press release did not disclose publication plans or if the work was peer-reviewed.

Source: NASA