Dust In The Wind… Black Hole Style

This artist’s impression shows the surroundings of the supermassive black hole at the heart of the active galaxy NGC 3783 in the southern constellation of Centaurus (The Centaur). Credit: ESO/M. Kornmesser

Over the years, researchers have taken myriad observations of black holes and their environs, but now ESO’s Very Large Telescope Interferometer is giving us the most detailed look of the dust around a black hole at the center of an active galaxy ever obtained. Originally expected to be contained within the ring-shaped torus around the black hole, the observation held a surprise as astronomers discovered that a significant amount of the dust was located both above and below the torus. What can this mean? According to the latest findings and contrary to popular theory, it is possible the dust is being evacuated from the region as a cool wind.

For the last two decades, astronomers have discovered that nearly all galaxies harbor a black hole at their hearts. In many cases, these monsters increase in size by accreting matter from the immediate vicinity. This, in turn, is responsible for the creation of active galactic nuclei (AGN), one of the most energetic objects in the Universe. Surrounding the super-luminous giants are rings of cosmic dust which originate from space – drawn in like water swirling down a dark drain. According to theory, the intense infrared radiation exerted by AGN must have originated from these dusty eddies.

Thanks to the powerful eye of the Very Large Telescope Interferometer (VLTI) at ESO’s Paranal Observatory in Chile, astronomers have now seen something new in a nearby active galaxy cataloged as NGC 3783. While they observed the expected hot dust clocking in at some 700 to 1000 degrees Celsius, what they also observed confounded them… Huge amounts of cooler dust both above and below the main torus.

As Sebastian Hönig (University of California Santa Barbara, USA and Christian-Albrechts-Universität zu Kiel, Germany), lead author of the paper presenting the new results, explains, “This is the first time we’ve been able to combine detailed mid-infrared observations of the cool, room-temperature dust around an AGN with similarly detailed observations of the very hot dust. This also represents the largest set of infrared interferometry for an AGN published yet.”

Is this a black hole teething ring? From their observations, the researchers suspect the newly-discovered dust is flowing outward from the central black hole. This means the wind most likely plays a critical part in the tangled relationship of both the black hole and its surroundings. Apparently the black hole pulls immediate material into it, but the incredible amount of radiation this produces also seems to be pushing it away. Scientists are far from clear as to how these two processes work together, but the discovery of this dusty wind could lead to a better understanding of their evolution.

To get the resolution needed to study the core area of NGC 3783, astronomers needed to use the combined power of the Unit Telescopes of ESO’s Very Large Telescope. Through this union, an interferometer is created – one capable of “seeing” with the equivalent of a 130-meter telescope.

Another team member, Gerd Weigelt (Max-Planck-Institut für Radioastronomie, Bonn, Germany), explains, “By combining the world-class sensitivity of the large mirrors of the VLT with interferometry we are able to collect enough light to observe faint objects. This lets us study a region as small as the distance from our Sun to its closest neighbouring star, in a galaxy tens of millions of light-years away. No other optical or infrared system in the world is currently capable of this.”

What do these new observations mean to the world of astronomy? It might very well change the pattern of how we currently understand AGN. With proof that dust is being expelled by intense radiation, new models must be created – models which include this recent information of how dust can be distributed.

Hönig concludes, “I am now really looking forward to MATISSE, which will allow us to combine all four VLT Unit Telescopes at once and observe simultaneously in the near- and mid-infrared — giving us much more detailed data.” MATISSE, a second generation instrument for the VLTI, is currently under construction.

Original Story Source: ESO News Release.

Spectacular Billion Pixel Panorama from NASA’s Curiosity Mars Rover

This is a cropped, reduced version of panorama from NASA's Mars rover Curiosity with 1.3 billion pixels in the full-resolution version see full panorama below. It shows Curiosity at the "Rocknest" site where the rover scooped up samples of windblown dust and sand. Curiosity used three cameras to take the component images on several different days between Oct. 5 and Nov. 16, 2012. Viewers can explore this image with pan and zoom controls at http://mars.nasa.gov/bp1/. Credit: NASA/JPL-Caltech/MSSS

This is a cropped, reduced version of panorama from NASA’s Mars rover Curiosity with 1.3 billion pixels in the full-resolution version. See full panorama below. It shows Curiosity at the “Rocknest” site where the rover scooped up samples of windblown dust and sand. Curiosity used three cameras to take the component images on several different days between Oct. 5 and Nov. 16, 2012. Viewers can explore this image with pan and zoom controls at http://mars.nasa.gov/bp1/. Credit: NASA/JPL-Caltech/MSSS
Updated with link to interactive Gigapan version
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NASA’s newly produced and absolutely spectacular panorama from the Curiosity mega rover offers armchair explorers back on Earth a mammoth 1.3 billion pixels worth of Mars in all its colorful glory.

And everyone can move back and forth around the interactive panorama and zoom in – with special embedded tools- to your hearts delight in exquisite detail at the ‘Rocknest’ site where the rover spent her first extended science stay in late 2012.

This extra special Rocknest panorama is the first NASA- produced view comprising more than a billion pixels from the surface of the Red Planet.

It offers a full 360 degree panoramic view around the rover encompassing breathtaking vistas of Mount Sharp and the eerie rim of Gale Crater, some 20 miles distant.

Mount Sharp rises 3.4 miles (5.5 km) high and is the target destination. The team hopes Curiosity will arrive at the base of Mount Sharp perhaps late this year or early in 2014.

The ‘Rocknest’ scene was assembled from nearly 900 raw images snapped by three different cameras among the 17 total that Curiosity uses as she trundles across the crater floor in search of the ingredients of life.

Billion-Pixel View From Curiosity at Rocknest, Raw Color.  This full-circle, reduced view combined nearly 900 images taken by NASA's Curiosity Mars rover, generating a panorama with 1.3 billion pixels in the full-resolution version. The view is centered toward the south, with north at both ends. It shows Curiosity at the "Rocknest" site where the rover scooped up samples of windblown dust and sand. Curiosity used three cameras to take the component images on several different days between Oct. 5 and Nov. 16, 2012. Credit: NASA/JPL-Caltech/MSSS
Billion-Pixel View From Curiosity at Rocknest, Raw Color. This full-circle, reduced view combined nearly 900 images taken by NASA’s Curiosity Mars rover, generating a panorama with 1.3 billion pixels in the full-resolution version. The view is centered toward the south, with north at both ends. It shows Curiosity at the “Rocknest” site where the rover scooped up samples of windblown dust and sand. Curiosity used three cameras to take the component images on several different days between Oct. 5 and Nov. 16, 2012. Credit: NASA/JPL-Caltech/MSSS

The panorama was created by Bob Deen of the Multi-Mission Image Processing Laboratory at NASA’s Jet Propulsion Laboratory, Pasadena, Calif, where the mission is managed on a daily basis.

“It gives a sense of place and really shows off the cameras’ capabilities,” said Deen in a statement. “You can see the context and also zoom in to see very fine details.”

Check here for the full, billion pixel interactive cylindrical and panoramic viewers

Download the full image –here.

“Rocknest” was a windblown ripple of sand dunes that Curiosity drove to after departing from the touchdown site at ‘Bradbury Landing’ and thoroughly investigated in October and November 2012.

It was at ‘Rocknest’ where the six wheeled rover famously deployed her robotic arm to scoop into the Martian dirt for the very first time and then delivered those first grains to the duo of analytical chemistry labs inside her belly that lie at the heart of Curiosity’s science mission.

Deen assembled the color product using 850 raw images from the 100 mm telephoto camera of Curiosity’s Mast Camera instrument, supplemented with 21 more from the Mastcam’s wider-angle 34 mm camera.

In order to take in the rover itself, the view also included 25 black-and-white raw images from the Navigation Camera on the Mast.

All the images were taken between Oct. 5 and Nov. 16, 2012 while the rover was stationary at Rocknest.

Link to the interactive GigaPan version – here

And check this link to a new NASA JPL Curiosity gallery on the GigaPan website – here

Because the images were captured over many days and at different times of day, the lighting and atmospheric clarity varies – especially in distant views to the crater rim.

Since landing on August 6, 2012, Curiosity has already accomplished her primary goal of finding a habitable zone at Gale Crater with an environment that could once of supported Martian microbial life – at the current worksite at ‘Yellowknife Bay.’

Time lapse context view of Curiosity maneuvering her robotic arm to conduct close- up examination of windblown ‘Rocknest’ ripple site.  Curiosity inspects “bootlike” wheel scuff mark with the APXS (Alpha Particle X-Ray Spectrometer) and MAHLI (Mars Hand Lens Imager) instruments positioned on the rotatable turret at the arm’s terminus. Mosaic stitched from Navcam images on Sols 57 & 58 shows the arm in action just prior to 1st sample scooping here. Eroded rim of Gale Crater rim is visible on the horizon. Credit: NASA/JPL-Caltech/Ken Kremer (kenkremer.com)/Marco Di Lorenzo
Time lapse context view of Curiosity maneuvering her robotic arm to conduct close- up examination of windblown ‘Rocknest’ ripple site. Curiosity inspects “bootlike” wheel scuff mark with the APXS (Alpha Particle X-Ray Spectrometer) and MAHLI (Mars Hand Lens Imager) instruments positioned on the rotatable turret at the arm’s terminus. Mosaic stitched from Navcam images on Sols 57 & 58 shows the arm in action just prior to 1st sample scooping here. Eroded rim of Gale Crater rim is visible on the horizon. Credit: NASA/JPL-Caltech/Ken Kremer (kenkremer.com)/Marco Di Lorenzo

The 1 ton robot is equipped with 10 state-of-the-art science instruments with research capabilities that far surpass any prior landed mission and is in the middle of the 2-year primary mission to the Red Planet.

Meanwhile, Curiosity’s older sister rover Opportunity has also discovered clay minerals and a habitable zone on the opposite side of the Red Planet – details here.

And don’t forget to “Send Your Name to Mars” aboard NASA’s MAVEN orbiter- details here. Deadline: July 1, 2013

Ken Kremer

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Learn more about Mars, Curiosity, Opportunity, MAVEN, LADEE and NASA missions at Ken’s upcoming lecture presentations

June 23: “Send your Name to Mars on MAVEN” and “CIBER Astro Sat, LADEE Lunar & Antares Rocket Launches from Virginia”; Rodeway Inn, Chincoteague, VA, 8 PM

Curiosity scooped 5 times into Martian soil at Rocknest windblown ripple and delivered samples to the SAM chemistry instrument for analysis. This color mosaic was stitched together from hi-res color images taken by the robots 34 mm Mastcam camera on Sols 93 and 74. Credit: NASA / JPL-Caltech /MSSS/Ken Kremer (kenkremer.com)/Marco Di Lorenzo
Curiosity scooped 5 times into Martian soil at Rocknest windblown ripple and delivered samples to the SAM chemistry instrument for analysis. This color mosaic was stitched together from hi-res color images taken by the robots 34 mm Mastcam camera on Sols 93 and 74. Credit: NASA / JPL-Caltech /MSSS/Ken Kremer (kenkremer.com)/Marco Di Lorenzo

3-D Printer Passes Key Step On Road to Space Station

A test of the 3-D printer in a microgravity-like environment simulated on an airplane that flies parabolas. Credit: Made in Space

The joke about home renovation projects is it takes at least three trips to the hardware store to finish the work. In space, of course, spare parts are a lot harder to come by, meaning astronauts might have to wait for a spacecraft shipment, if, say, the toilet breaks. (Yes, this yucky situation has happened before.)

Some spare parts could be manufactured in space as early as next year, though, providing a 3-D printer passes all the preliminary steps. It recently got a big boost in that direction after passing its microgravity tests successfully, but there are still environmental tests to come, said the company that was behind the work.

“The 3-D printer we’re developing for the ISS is all about enabling astronauts today to be less dependent on Earth,” stated Noah Paul-Gin, the lead for the microgravity experiment.

“The version that will arrive on the ISS next year has the capability of building an estimated 30% of the spare parts on the station, as well as various objects such as specialty tools and experiment upgrades.”

A close-up of the 3-D printer prototype made by Made in Space. Credit: Made in Space
A close-up of the 3-D printer prototype made by Made in Space. Credit: Made in Space

The firm tested the printer during four flights that, in part, simulated microgravity. They were on a specially designed airplane that flies parabolas, meaning it climbs and then briefly simulates, roller-coaster style, microgravity during the plunge before climbing again. (Each microgravity test is only about 30 seconds long.)

“The unique challenges posed by off-Earth 3-D printing require technology and hardware specifically adapted for space. In these microgravity tests, Made in Space assessed layer adhesion, resolution and part strength in the microgravity environment,” the company added.

After Made in Space received a contract for the 3D printer a couple of years ago, it flew three prototype versions that collectively were in microgravity 32 times.

If this printer makes it to space and performs well, it will add to the excitement of 3-D printing that has been swirling around the space community lately.

A study led by NASA recently investigated the possibility of using 3-D printing in association with creating robots to work on asteroids. Astronauts on the station could also have a food replicator of sorts on board the station, too, if a grant awarded to Systems & Materials Research Corperation this May pans out.

Source: Made In Space

“Horizons” — Gorgeous New Views from Dakotalapse

Three-image panorama of the Milky Way arching of the Badlands of South Dakota. Credit and copyright: Randy Halverson/Dakotalapse

We’ve oohed and ahhed many times over the handiwork of Randy Halverson and his Dakotalapse timelapse videos and imagery of the night sky. He may have outdone himself with his latest timelapse, called “Horizons.” Randy shot the footage from April – October 2012, mostly in South Dakota, but also some at Devils Tower in Wyoming.

“Growing up in South Dakota the landscape itself can be beautiful at times,” Randy says, “but that doesn’t compare to what the sky can do, especially at night.” Not only is the imagery absolutely breathtaking, but the accompanying music is an original called “I Forever” by Bear McCreary (The Walking Dead, Defiance, Battlestar Galactica, etc) his brother Brendan McCreary and his band Young Beautiful in a Hurry.

There’s a four-minute version below, but also available on Vimeo On Demand is a full 30-minute feature . Enjoy!!

The lead image and this one below are recent images from Randy that he has posted on Flickr.

Mirrored Aurora - Aurora mirrors off a small lake in central South Dakota on June 6, 2013. Credit and copyright: Randy Halverson/Dakotalapse.
Mirrored Aurora – Aurora mirrors off a small lake in central South Dakota on June 6, 2013. Credit and copyright: Randy Halverson/Dakotalapse.

Horizons from Randy Halverson on Vimeo.

Morpheus Aborts, Then Recovers For a Second Go In Tether Test

Morpheus during an April 2012 test. Credit: Joe Bibby

The above video should satisfy your daily need for rocket foom. Morpheus — a NASA testbed for vertical landing systems — did two firing tests this week that produced a fair amount of the usual fire and smoke, as you can see above.

You’ll actually see two separate firings in that video. In the first one, the lander strayed out of its safety zone and did a soft abort. The second test, NASA stated, “was a complete success.”

The first lander of the program crashed and burned in a test failure in August 2012, but officials recently praised the program for the progress it has made since then.

“Although a hardware failure led to the loss of the original vehicle last August, the failure and our internal investigation gave us valuable insight into areas that needed improvement,” a Project Morpheus blog post from May stated.

“The vehicle may look largely the same as the previous version, but there are numerous changes that have been incorporated.  We have now implemented 70 different upgrades to the vehicle and ground systems to both address potential contributors to the test failure, and also to improve operability and maintainability.”

In the long run, NASA aims to use Morpheus as a “vertical test bed” for environmentally friendly propellants, as well as for automatic advances in landing and hazard detection.

The vehicle is advertised as big enough to land 1,100 pounds of cargo on the moon if it was placed nearby.

Check out more information about the program at the Project Morpheus website.

Did a Piece of Mir Really Land in Massachusetts?

Screenshot closeup of the Amesbury Mass. find.

We love a good space debris mystery. Hey, who doesn’t, right?  Regular readers of Universe Today know that it’s a shooting gallery out there, from meteor fireballs caught on dashboard cams to rogue space junk reentries lighting up our skies. 

But an unusual story that made its rounds across the internet this past weekend caught our attention. What at first glance was a simple “Man finds space rock” story morphed into an extraordinary claim, which, in the words of the late great Carl Sagan, “demand extraordinary evidence.”

The find was made by Phil Green of Amesbury, Massachusetts. Mr. Green was searching the local riverbed for arrowheads when he came across the unusual find. The black pitted rock immediately struck him as something bizarre.  It didn’t register as metallic to his metal detector, but Mr. Green kept it in his backyard for about five years until it was noticed by a friend.

“I didn’t really think much of it, and then a fellow came over, saw it and said that’s a meteor,” Green told local reporters.

From here, the story takes a strange turn. Green told local reporters that the rock was sent off for analysis, only to be returned to him just a few weeks ago. The analysis confirmed that the rock was indeed from space… sort of. It also stated that the vitreous material “shows a composition similar to that used in ballast by the Soviet space program starting in the mid-1980s.”

And the word was out. The media quickly ran with the “Man finds a piece of Mir” story.

There are just a few problems with the tale. Mir reentered in 2001, six years before the 2007. A few articles do bother to note this, mentioning that Mir ended its career in the “so-called spacecraft cemetery of the southern Pacific Ocean,” about as far away from Massachusetts as you can get.

A few articles do also mention the possibility of a reentry of a Progress resupply vehicle being a potential source, or perhaps an unrelated Russian space vehicle.

But there seems to be a potential problem of the certification. Several articles state that the piece of debris coming from Mir was “confirmed by NASA.” However, Universe Today contacted NASA Chief Scientist for Orbital Debris Nicholas L. Johnson and NASA Headquarters official Joshua Buck, who both told us that no such NASA validation exists. Mr. Johnson went on to tell Universe Today that, “The NASA Orbital Debris Program Office has not been presented with any claim regarding debris from the Mir space station,” adding “I can tell you that it is not possible for debris from the Mir reentry to have landed in the U.S.”

A name that occasionally turns up in reports online as validating the find (withheld by request) also tells Universe Today that they had nothing to do with the discovery. Mr. Green or the original validation source  have thus far been unavailable for comment.

We did uncover two documented reentries that occurred over the general region over the last few decades. One is the reentry of Mir-R 1986-017B (The rocket booster that launched the core module of Mir) seen from a trans-Atlantic airliner on February 24th 1986 about 500 kilometres off of the east coast of Newfoundland. Another possible suspect is the June 26/27th 2004 reentry of a SL-12 auxiliary rocket motor with the NORAD ID 1992-088E, seen to the west from New Jersey to Ontario.

Like the International Space Station, Mir was placed in a 51.6° inclined orbit. This made it accessible from the Baikonur Cosmodrome as well as visits from the U.S. Space Shuttle. Payloads going to and from the station would cover an identical ground track ranging from 51.6° north to south latitude.

The story is also reminiscent of the reentry of debris from Sputnik 4, which struck a small town in Wisconsin in 1962. This was analyzed by mineralogist Ursula Marvin and confirmed to be of Russian origin.

A Progress spacecraft inbound for docking with the International Space Station. (Credit: NASA).
A Progress spacecraft inbound for docking with the International Space Station. (Credit: NASA).

Probably the biggest question in our minds is: what links the object back to an errant Russian spacecraft? What do they use for ballast, anyhow? How did they arrive at the often quoted “85% certainty?” of the object’s origin?

Still, the find does look like something interesting. The pitting and the melted fusion crust are all reminiscent of reentry. We’ll keep researching this story, and for the time being we’ll leave it up to you, the diligent and insightful readers of Universe Today, to make up your own minds on this strange and interesting tale.

Say Cheese: Cassini to Snap Another “Pale Blue Dot” Picture of Earth

Mosaic of Saturn seen in eclipse in September 2006. Earth is the bright dot just inside the F ring at upper left. (CICLOPS/NASA/JPL-Caltech/SSI)

Citizens of Earth, get ready for your Cassini close-up: once again the spacecraft is preparing to capture images of Saturn positioned between it and the Sun, allowing for incredible views of the ring system and its atmosphere — and also a tiny “pale blue dot” in the distance we call home.

Earth seen from Cassini (NASA/JPL/SSI)
Earth seen from Cassini (NASA/JPL/SSI)

The mosaic above was composed of images captured during such an eclipse event in September 2006, and quickly became an astronomical sensation. It’s not often we get an idea of what we look like from so far away, and seeing our entire world represented as a small speck of light nestled between Saturn’s rings is, to me anyway, both impressive and humbling.

Humbling because of how small we look, but impressive because as a species we have found a way to do it.

And next month, on Friday, July 19 between 21:27 and 21:42 UTC (5:27 – 5:42 p.m. EDT) Cassini will do it again.

“Ever since we caught sight of the Earth among the rings of Saturn in September 2006 in a mosaic that has become one of Cassini’s most beloved images, I have wanted to do it all over again, only better,” said Cassini imaging team leader, Carolyn Porco. “And this time, I wanted to turn the entire event into an opportunity for everyone around the globe, at the same time, to savor the uniqueness of our beautiful blue-ocean planet and the preciousness of the life on it.”

Porco was involved in co-initiating and executing the famous “Pale Blue Dot” image of Earth taken by NASA’s Voyager 1 from beyond the orbit of Neptune in 1990.

“It will be a day for all the world to celebrate,” she said.

The intent for the upcoming mosaic is to capture the whole scene, Earth and Saturn’s rings from one end to the other, in Cassini’s red, green and blue filters that can be composited to form a natural color view of what our eyes might see at Saturn. Earth and the Moon will also be imaged with a high resolution camera — something not yet done by Cassini.

We can all consider ourselves pretty lucky, too… this is the first time in history that we humans will know in advance that our picture is going to be taken from nearly a billion miles away.

“While Earth will be only about a pixel in size from Cassini’s vantage point 898 million miles [1.44 billion kilometers] away, the Cassini team is looking forward to giving the world a chance to see what their home looks like from Saturn,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory. “With this advance notice, we hope you’ll join us in waving at Saturn from Earth, so we can commemorate this special opportunity.”

So on July 19, remember to look up and wave… Cassini will be watching!

Read more on the CICLOPS news release here and on the NASA/JPL Cassini mission site here.

“That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives… There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.”

– Carl Sagan

Book Review: The Milky Way, An Insider’s Guide

About 70 pages into The Milky Way, An Insider’s Guide, a strange craving for hamburgers overtook me.

The text of William H. Waller, an astronomer and author, was in the midst of a discussion of a kind of organic molecule called PAHs, or polycyclic aromatic hydrocarbons. As I was reading about the Spitzer Space Telescope’s discoveries in this field, the last sentence in the paragraph struck me:

“On Earth, PAHs are as familiar to us as the mouth-watering aromas of a barbecued hamburger, the sweetly acrid odors of burning tobacco, and the choking fumes behind a diesel bus,” Waller wrote. “If we had big enough nostrils, what would our home galaxy smell like?”

I’m never going to read about PAHs again without wanting to run to that greasy joint nearby my place. Or, I guess, run in the opposite direction from the nearest bus stop.

A digital all-sky mosaic of our view of the Milky Way from Earth, assembled from more than 3,000 individual CCD frames. Credit: Axel Mellinger. Click on image to view a zoomable panorama.
A digital all-sky mosaic of our view of the Milky Way from Earth, assembled from more than 3,000 individual CCD frames. Credit: Axel Mellinger.

Waller’s book is designed as a reference guide for those with a serious interest in astronomy, but who perhaps are just starting to think about taking it in school. Another audience could be the serious amateur astronomer wanting to understand more about telescopic targets.

While not light cottage reading, Waller isn’t afraid to throw in references to popular culture or to drop in humor now and then, much like a kindly Astronomy 101 professor trying to snap your attention back when it might be wandering.

On that note, this illustration in the book (with some important context) may be my favorite astronomy textbook image of all time. It’s another example of how science can, kinda sorta, meet science fiction.

The USS Enterprise has many uses for its deflector shields, including repelling the Borg (Paramount Pictures)
You will find Star Trek references in this book, we promise you. (Paramount Pictures)

The breadth of material Waller covers is astonishing. One 43-page chapter is essentially a history of how we looked at the sky mythologically, philosophically and of course scientifically — a feat that is more interesting when you realize a goodly number of those pages are actually in-context, interesting illustrations.

The book’s bulk, though, looks to summarize astronomical phenomena. It’s definitely not for the beginning reader; for example, the term “nebula” is referred to several times before finally being defined some pages into the book. But if you know what Waller is aiming at, you’ll learn quite a bit.

The Hertzsprung-Russell Diagram.
The Hertzsprung-Russell Diagram.

The book purports to be about galaxies, but much of it is also devoted to what I think of as hacking the Hertzsprung-Russell diagram showing the types of stars in relation to each other.

Three full chapters are devoted to star birth, the lives of stars and stellar afterlives (y’know, supernovae and the like.) This makes perfect sense as galaxies are collections of stars, so it is only by studying these individual members that we can truly appreciate what a galaxy is about.

The more serious reader will be pleased to see equations included (such as calculating parallax) and a detailed explanation of Drake’s Equation showing the factors behind the probability of finding extraterrestrial life.

So to sum up: definitely not for the person with a nascent interest in astronomy, but a valuable reference for those looking to learn about it seriously. As a space journalist, I’ll definitely keep this book on my shelf.

Venus’ Winds Are Mysteriously Speeding Up

Over the past six years wind speeds in Venus' atmosphere have been steadily rising (ESA)

High-altitude winds on neighboring Venus have long been known to be quite speedy, whipping sulfuric-acid-laden clouds around the superheated planet at speeds well over 300 km/h (180 mph). And after over six years collecting data from orbit, ESA’s Venus Express has found that the winds there are steadily getting faster… and scientists really don’t know why.

Cloud structures in Venus' atmosphere, seen by Venus Express' Ultraviolet, Visible and Near-Infrared Mapping Spectrometer (VIRTIS) in 2007 (ESA)
Cloud structures in Venus’ atmosphere, seen by Venus Express’ Ultraviolet, Visible and Near-Infrared Mapping Spectrometer (VIRTIS) in 2007 (ESA)

By tracking the movements of distinct features in Venus’ cloud tops at an altitude of 70 km (43 miles) over a period of six years — which is 10 of Venus’ years — scientists have been able to monitor patterns in long-term global wind speeds.

What two separate studies have found is a rising trend in high-altitude wind speeds in a broad swath south of Venus’ equator, from around 300 km/h when Venus Express first entered orbit in 2006 to 400 km/h (250 mph) in 2012. That’s nearly double the wind speeds found in a category 4 hurricane here on Earth!

“This is an enormous increase in the already high wind speeds known in the atmosphere. Such a large variation has never before been observed on Venus, and we do not yet understand why this occurred,” said Igor Khatuntsev from the Space Research Institute in Moscow and lead author of a paper to be published in the journal Icarus.

Long-term studies based on tracking the motions of several hundred thousand cloud features, indicated here with arrows and ovals, reveal that the average wind speeds on Venus have increased from roughly 300 km/h to 400 km/h over the first six years of the mission. (Khatuntsev et al.)
Long-term studies based on tracking the motions of several hundred thousand cloud features, indicated here with arrows and ovals, reveal that the average wind speeds on Venus have increased from roughly 300 km/h to 400 km/h over the first six years of the mission. (Khatuntsev et al.)

A complementary Japanese-led study used a different tracking method to determine cloud motions, which arrived at similar results… as well as found other wind variations at lower altitudes in Venus’ southern hemisphere.

“Our analysis of cloud motions at low latitudes in the southern hemisphere showed that over the six years of study the velocity of the winds changed by up 70 km/h over a time scale of 255 Earth days – slightly longer than a year on Venus,” said Toru Kouyama from Japan’s Information Technology Research Institute. (Their results are to be published in the Journal of Geophysical Research.)

Both teams also identified daily wind speed variations on Venus, along with shifting wave patterns that suggest “upwelling motions in the morning at low latitudes and downwelling flow in the afternoon.” (via Cloud level winds from the Venus Express Monitoring Camera imaging, Khatuntsev et al.)

A day on Venus is longer than its year, as the planet takes 243 Earth days to complete a single rotation on its axis. Its atmosphere spins around it much more quickly than its surface rotates — a curious feature known as super-rotation.

“The atmospheric super-rotation of Venus is one of the great unexplained mysteries of the Solar System,” said ESA’s Venus Express Project Scientist Håkan Svedhem. “These results add more mystery to it, as Venus Express continues to surprise us with its ongoing observations of this dynamic, changing planet.”

Read more here on ESA’s Venus Express page.

Will Comet ISON Dazzle our Skies? An Expert Weighs In

ISON as seen by Hubble earlier this spring. (Credit: NASA/ESA/Z. Levay/STScl).

Comets are the big “question marks” of observational astronomy. Some, such as Comet Hyakutake and the Great Daylight Comet of 1910 present themselves seemingly without warning and put on memorable displays. Others, such as the infamous Comet Kohoutek or Comet Elenin, fizzle and fail to perform up to expectations after a much anticipated round of media hype.

And then there’s the case of Comet C/2012 S1 ISON. Discovered on September 21st, 2012 by Artyom Novichonok and Vitali Nevski while conducting the International Scientific Optical Network (ISON) survey, Comet ISON has captivated public interest. The media loves a good comet, or at least the promise of one.

But will Comet ISON perform up to expectations? Recently, veteran comet hunter and observer John Bortle weighed in on a Sky & Telescope post and an email interview with Universe Today on what we might expect to see this fall.

Dozens of comets are discovered every year. Most amount to nothing – a handful, like this year’s comet 2011 L4 PanSTARRS or 2012 F6 Lemmon, may become interesting binocular objects.

Part of what alerted astronomers that Comet ISON may become something special was its extreme discovery distance of 6.7 astronomical units (A.U.s) meaning it should be an intrinsically bright object, coupled with its close approach of 0.012 A.U.s (1.1 million kilometres, accounting for the solar radius) from the surface of the Sun at perihelion.

Universe Today recently caught up with Mr. Bortle, who had the following to say above tentative prospects for Comet ISON in late 2013:

“Comets coming into the near-solar neighborhood from the Oort Cloud for the very first time tend to behave rather differently from most of their other icy brethren. They often will show considerable early activity while still far from the Sun, giving a false sense of their significance. Only when they have ventured to within about 1.5-2.0 astronomical units of the Sun do they begin to reveal their true intrinsic nature in the way of brightness and development. When discovered far from the Sun, this situation has misled astronomers time and again into announcing that a grandiose display is in the offing, only to have the comet ultimately turn out to be a general disappointment. There have been exception to this, but they are rare indeed.”

Comet ISON bears similar characteristics to many of the great sungrazing comets of the past. In the last few months, word has made rounds that Comet ISON may be underperforming, stagnating around magnitude +16 (10,000 times fainter than naked eye visibility) as it crosses the expanse of the asteroid belt between Jupiter and Mars.

Bortle, however, cautioned against writing off ISON just yet in a recent message board post. “With this comet’s exceedingly small perihelion distance, the ultimate situation is less clear.” He also continues to note that the prospects for ISON are “really difficult to predict at the moment,” but estimates that Comet ISON “will not actually attain naked eye brightness until just a week or two before perihelion passage.”

Regarding naked eye visibility of Comet ISON, Mr. Bortle also told Universe Today:

“In all probability this will not occur until around early to mid-November. It will not become any sort of impressive sight before disappearing into the morning twilight only a couple of weeks thereafter.”

And that’s the big question that may make the difference between a fine binocular comet and the touted “Comet of the Century…” Will this comet survive its perihelion passage on November 28th?

Concerning the comet’s perihelion passage, Mr. Bortle told Universe Today:

“This is currently a matter of some concern to me. Basing my answer on ISON’s apparent brightness when it was last seen before disappearing into the evening twilight recently suggests that it might be close in intrinsic brightness to the survival/non-survival level for such an extremely close encounter with the Sun. We will know much better once we can view ISON again in September.”

Comet Ikeya-Seki was another sungrazing comet that went on to become a splendid naked eye comet in 1965. The late 1880’s hosted a slew of memorable comets, including two long-tailed sungrazers, one each in 1880 and 1887.

In more recent times, Comet C/2011 W3 Lovejoy survived its December 16th, 2011 perihelion passage 140,000 kilometres from the surface of the  Sun to become the surprise hit for southern hemisphere observers.

“IF” comet ISON breaks a negative magnitude, it’ll join the ranks on the top brightest comets since 1935. If it tops -10th magnitude, it’ll best Comet Ikeya-Seki at its maximum in 1965. The magic “brighter than a Full Moon” threshold sits right about at magnitude -12.5, but Bortle cautions that this peak brightness will only persist during the hours surrounding perihelion, when the comet will be very close to the Sun and difficult to see.

Mr. Bortle also voiced a concern to Universe Today that “the initial announcements by professional astronomers concerning ISON’s potential future brightness (“Brighter than the Full Moon”, etc.) were wildly excessive, as was the idea that the comet would be obvious to the general public in the daytime sky as it rounded the Sun in late November. This claim was totally unjustified from the word go.” Mr Bortle also warns that this may be  “headed us down the exact same road as the Kohoutek fisaco of 1973/74.”

We’re currently losing Comet ISON behind the Sun as it crosses through the constellation Gemini, not return to morning skies until late August. The comet will cross the orbit of Mars in early October and should also cross the +10th magnitude threshold and become visible in binoculars and small telescopes around this date.

The track of Comet ISON through the constellations Gemini, Cancer and Leo prior to perihelion. (Credit: NASA/GSFC/Axel Mellinger).
The track of Comet ISON through the constellations Gemini, Cancer and Leo prior to perihelion. (Credit: NASA/GSFC/Axel Mellinger).

From October on in, things should get really interesting. Mr. Bortle predicts that the comet will “develop more slowly in the autumn sky than initially thought,” and won’t become a naked eye object until around November 10th or so. What this sort of lag might do to the internet pundits and prognosticators might be equally interesting to watch.

ISON will also track near some interesting morning objects as seen from Earth, including Mars (October 18th), Spica (November 18th), and Mercury & Saturn low in the dawn on November 26th. It will also have another famous comet nearby on November 25th (photo op!) short period Comet 2P Encke.

If Comet ISON survives perihelion, the true show could begin in early December. Comet ISON will re-emerge in the dawn skies, passing a pairing of Mercury and the very old crescent Moon on December 1st. Comet tails are even less predictable than comet magnitudes, but if Comet ISON is to unfurl a long photogenic tail, the weeks leading up to Christmas may be when it does it.

The projected view of Comet ISON from 30 degrees north latitude 30 minutes prior to local sunrise on December 1st. The orbital path of the comet and the ecliptic are also depicted. (Created by the author in Starry Night).
The projected view of Comet ISON from 30 degrees north latitude 30 minutes prior to local sunrise on December 1st. The orbital path of the comet and the ecliptic are also depicted. (Created by the author in Starry Night).

Mr. Bortle predicts a 10 to 15 degree long tail for a post-perihelion ISON as it passes through the constellation Ophiuchus into morning skies. It may become a “headless wonder” similar to the fan-shaped display put on by Comet 2011 L4 PanSTARRS earlier this spring. We’ve even seen models projecting a great fan-shaped dust tail seeming to “loop” around the Sun as seen from our Earthly vantage point!

All interesting conjecture to watch unfold as Comet ISON approaches perihelion this November. Hopefully, the hysteria that follows great cometary apparitions won’t reach a fevered pitch, though we’ve already had to put some early conspiracies to bed surrounding comet ISON.

Will ISON be the “Comet of the Century?” Watch this space… we’ll have more on the play-by-play action as it approaches!

-Read John Bortle’s predictions for Comet ISON in his recent Sky & Telescope post.