Bob King, Author at Universe Today

August 3, 2014December 23, 2015 by Bob King

Getting to Know Comet 67P/Churyumov-Gerasimenko

Comet 67P/Churyumov-Gerasimenko at 621 miles (1,000 km) on August 1. Wow! Look at that richly-textured surface. This photo has higher resolution than previous images because it was taken with Rosetta's narrow angle camera. The black spot is an artifact. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

We’re finally getting to know the icy nucleus behind comet 67P/Churyumov-Gerasimenko. For all the wonder that comets evoke, we on Earth never see directly what whips up the coma and tail. Even professional telescopes can’t burrow through the dust and vapor cloaking the nucleus to distinguish the clear outline of a comet’s heart. The only way to see one is to fly a camera there.

Asteroids we've seen up close show cratered surfaces similar to yet different from much of the cratering on comets. Credit: — Asteroids we’ve seen up close show cratered surfaces similar to yet different from much of the cratering so far seen on comets. Not to scale. Credit: NASA except for Steins (ESA)

Rosetta took 10 years to reach 67P/C-G, a craggy, boot-shaped body that resembles an asteroid in appearance but with key differences. Asteroids shown in close up photos often display typical bowl-shaped impact craters. From the photos to date, 67P/C-G’s ‘craters’ look shallow and flat in comparison. Were they impacts smoothed by ice flows over time? Did some of the dust and vapor spewed by the comet settle back on the surface to partially bury and soften the landscape?

Comet 81P/Wild 2 photographed during the Stardust mission in 2004. Wild 2 measures 1.03 x 1.24 x 1.71 miles and goes around the sun once every 6.4 years. Its surfaced is riddled with flat-bottomed craters, some of which may also be gas vents from vaporized ice. Credit: NASA — Comet 81P/Wild 2 photographed during the Stardust mission in 2004. Wild 2 measures 1.03 x 1.24 x 1.71 miles and goes around the sun once every 6.4 years. Its surfaced is riddled with flat-bottomed depressions some of which may also vent gas from vaporizing ice. Click for more 81P/Wild 2 photos. Credit: NASA

While 67P is doubtless its own comet, it does share certain similarities with Comet 81P/Wild including at least a few crater-like depressions seen during NASA’s Stardust mission. In January 2004, the spacecraft gathered photos, measurements and dust samples during its brief flyby of the nucleus. Photos reveal pinnacles, flat-bottomed depressions and bright plumes or jets of vaporizing ice.

Some of the comets we've seen close up through the eyes of visiting spacecraft. Credit: NASA — Some of the comets we’ve seen close up through the eyes of visiting spacecraft. Credit: NASA

In a 2004 paper by Donald Brownlee and team, the group experimentally reproduced the flat-floored craters by firing projectiles into resin-coated sand baked a bit to make it cohere. Their results suggest the craters formed from impacts in loosely compacted material under the low-gravity conditions typical of small objects like comets. To quote the paper: “Most disrupted material stayed inside the cavity and formed a flat-floored deposit and steep cliffs formed the rim.” Icy materials mixed with dust may have also played a role in their appearance and other crater-like depressions called pit-halos.

Latest image of the comet taken by Rosetta's navigation camera on August 2, 2014. Credit: ESA/Rosetta/Navcam — Latest image of the comet taken by Rosetta’s navigation camera from a distance of only 311 miles (500 km) on August 2, 2014. The comet’s larger size in the field means fewer artifacts. Credit: ESA/Rosetta/Navcam

Speculation isn’t science, so I’ll stop here. So much more data will be streaming in soon, we’ll have our hands full. On Wednesday, August 6th, Rosetta will enter orbit around the nucleus and begin detailed studies that will continue through December 2015. Studying the new pictures now arriving daily, I’m struck by the dual nature of comets. We see an ancient landscape and yet one that looks strangely contemporary as the sun vaporizes ice, reworking the terrain like a child molding clay.

Comet 67P/Churyumov-Gerasimenko is well-placed in the mid-summer sky in Sagittarius but impossibly faint to see visually. Dave Herald's photo taken on August 21, 2014 shows only a tiny fuzz of magnitude +21. Credits: Background: Stellarium; David Herald — Comet 67P/Churyumov-Gerasimenko is well-placed in the mid-summer sky in Sagittarius but impossibly faint visually. Dave Herald’s photo taken on August 21, 2014 shows only a tiny fuzz of magnitude +21. Credits: Dave Herald; Stellarium

July 28, 2014December 23, 2015 by Bob King

Observing Alert – Delta Aquarid Meteor Shower Peaks This Week

A bright meteor from September 21, 1994. Credit: John Chumack.

With the southern Delta Aquarid meteor shower peaking tomorrow morning, the summer meteor-watching season officially begins. While not a rich shower from mid-northern latitudes, pleasant weather and a chance to see the flaming remains of a comet seem motivation enough to go out for a look. With a rate 10-15 per meteors an hour you’re bound to catch a few.

The farther south you live, the better it gets. Observers in the southern hemisphere can expect double that number because the shower’s radiant will be much higher in the sky. Any meteors flashing south of the radiant won’t get cut off by the southern horizon like they do further north.

The annual shower gets its name from Delta Aquarii, a dim star in the dim zodiac constellation Aquarius. You don’t need to know the constellations to enjoy the show, but if you know the general direction of the radiant you’ll be able to tell shower members from the nightly sprinkle of random meteors called sporadics. If you can trace the path of a meteor backward toward Aquarius, chances are it’s an Aquarid.

Delta Aquarid Meteors (2) on 07-30-2013 — A Southern Delta Aquarid meteor captured on July 30, 2013. Credit: John Chumack

There are actually two meteor showers in Aquarius active this time of year – the northern and southern Delta Aquarids. The northern version sprinkles fewer meteors and peaks in mid-August.

The Southern Deltas peak over the next two mornings – July 29 and 30 – but will be out all week. Both serve as a warm-up for the upcoming Perseid meteor shower that climaxes on August 12.

Tonight’s shower will suffer no interference from moonlight, making for ideal meteor watching. Unfortunately, Perseid rates will be reduced by a bright waning gibbous moon.

Don’t be surprised if you see a few Perseids anyway. The shower’s just becoming active. If you can draw a meteor’s trail back to the northeastern sky, it just might be a member. Read more about Perseid prospects from our own David Dickinson.

Meteors from Delta Aquarid meteor shower radiate from near the star Delta Aquarii not far from the bright star Fomalhaut in the Southern Fish low in the south before dawn. Stellarium

Nearly all meteor showers originate from clouds of sand to seed-sized bits of debris spewed by vaporizing comet ice as they swing near the sun. The Delta Aquarids may trace its origin to dust boiled off Comet 96P/Machholz.

The best time to watch the shower is in the early morning hours before dawn when the radiant rises in the south-southeastern sky above the bright star Fomalhaut. Try to get away from city lights. Point your lawn chair south and spend some time in heavenly contemplation as you wait for Aquarius to toss a few javelins of light your way.

July 26, 2014December 23, 2015 by Bob King

Comet Jacques Makes a ‘Questionable’ Appearance

Comet Jacques and IC 405, better known as the Flaming Star Nebula, align to create a temporary question mark in the sky this morning July 26. Credit: Rolando Ligustri

What an awesome photo! Italian amateur astronomer Rolando Ligustri nailed it earlier today using a remote telescope in New Mexico and wide-field 4-inch (106 mm) refractor. Currently the brightest comet in the sky at magnitude 6.5, C/2014 E2 Jacques has been slowly climbing out of morning twilight into a darker sky over the last two weeks. This morning it passed the Flaming Star Nebula in the constellation Auriga. Together, nebula and pigtailed visitor conspired to ask a question of the sky in a rare display of celestial punctuation. IC 405 is a combination emission-reflection nebula. Some of its light stems from starlight reflecting off grains of cosmic dust, but the deep red results from hydrogen excited to fluorescence by powerful ultraviolet light from those same stars. The depth of field hidden within the image is enormous: the nebula lies 1,500 light years away, the comet a mere 112 million miles or 75 million times closer. Coincidentally, the comet also glows in similar fashion. The short dust tail to the left of the coma is sunlight reflecting off minute grains of dust boiled from the nucleus. The long, straight tail is primarily composed of carbon monoxide gas fluorescing in ultraviolet light from the sun.

Follow Jacques in a small telescope or binoculars in its travels across Auriga into Perseus in the next two weeks before the moon interferes again. Comet positions are shown for 4 a.m. CDT every 5 days. Stars to magnitude +8.0. Click to enlarge. Source: Chris Marriott's SkyMap — Follow Jacques in a small telescope or binoculars in its travels across Auriga into Perseus during the next two weeks before the moonlight interferes. Comet positions are shown for 4 a.m. CDT every 5 days. Stars to magnitude +8.0. Click to enlarge. Source: Chris Marriott’s SkyMap

As Jacques swings toward its closest approach to Earth in late August, it’s gradually picking up speed from our perspective and pushing higher into the morning sky. A week ago, twilight had the upper hand. Now the comet’s some 20º high (two ‘fists’) above the northeastern horizon around 4 a.m. This morning I had no difficulty seeing it as a small, ‘fuzzy star’ in 10×50 binoculars. In my dusty but trusty 10-inch (25 cm) telescope at 76x, Comet Jacques was a dead ringer for one of those fuzzy dingle-balls hanging from a sombrero. I caught a hint of the very short dust tail but couldn’t make out the gas tail that shows so clearly in the photo. That will have to await darker skies.

A different perspective on Comet Jacques. This negative image, which accentuates detail in the comet's tails, was shot July 26, 2014 with an 8-inch (20 cm) telescope. Credit: Michael Jaeger — A different perspective on Comet Jacques. This negative image, which emphasizes details in the comet’s tails, was shot July 26, 2014 with an 8-inch (20 cm) telescope. Credit: Michael Jaeger

Maybe you’d like to try your own eyes on Jacques. Start with a pair of 40mm or larger binoculars or small telescope and use the map above to help you spot it. Oh, and don’t forget to keep an exclamation mark handy when you get that first look.

July 26, 2014December 23, 2015 by Bob King

NASA Preps for Nail-biting Comet Flyby of Mars

This graphic depicts the orbit of comet C/2013 A1 Siding Spring as it swings around the sun in 2014. On Oct. 19, the comet will have a very close pass at Mars. Its nucleus will miss Mars by about 82,000 miles (132,000 kilometers). The comet's trail of dust particles shed by the nucleus might be wide enough to reach Mars or might also miss it. Credit: NASA/JPL

As Comet C/2013 A1 Siding Spring inches closer to the Red Planet, NASA’s taking steps to protect its fleet of orbiting Mars spacecraft. On October 19, the comet’s icy nucleus will miss the planet by just 82,000 miles (132,000 km). That’s 17 times closer than the closest recorded Earth-approaching comet, Lexell’s Comet in 1770.

Comet C/2013 A1 (Siding Spring) on July 11, 2014. The comet, discovered by comet hunter Rob McNaught from Siding Spring Observatory in New South Wales, Australia on January 3, 2013, shows a bright coma and well-developed tail. Credit: Joseph Brimacombe — Comet C/2013 A1 (Siding Spring) on July 11, 2014. The comet, discovered by comet hunter Robert McNaught from Siding Spring Observatory in New South Wales, Australia on January 3, 2013, shows a bright coma and well-developed tail. Credit: Joseph Brimacombe

No one’s worried about the tiny nucleus doing any damage. It’ll zip right by. Rather it’s dust particles embedded in vaporizing ice that concern NASA planners. Dust spreads into a broad tail that could potentially brush Mars’ upper atmosphere and strike an orbiter. A single particle of debris half a millimeter across may not seem like your mortal enemy, but when it’s traveling at 35 miles (56 km) per second relative to the spacecraft, one hit could spell trouble.

“Three expert teams have modeled this comet for NASA and provided forecasts for its flyby of Mars,” explained Rich Zurek, chief scientist for the Mars Exploration Program at NASA’s Jet Propulsion Laboratory in Pasadena, California. “The hazard is not an impact of the comet nucleus, but the trail of debris coming from it. Using constraints provided by Earth-based observations, the modeling results indicate that the hazard is not as great as first anticipated. Mars will be right at the edge of the debris cloud, so it might encounter some of the particles — or it might not.”

The agency’s taking a prudent approach. NASA currently operates the Mars Reconnaissance Orbiter (MRO) and Mars Odyssey spacecraft with a third orbiter, MAVEN, currently on its way to the planet and expected to settle into orbit a month before the comet flyby. Teams operating the orbiters plan to have all spacecraft positioned on the opposite side of Mars when the comet is most likely to pass by.

Already, mission planners tweaked MRO’s orbit on July 2 to move it toward a safe position with a second maneuver to follow on August 27. A similar adjustment is planned for Mars Odyssey on August 5 and October 9 for the Mars Atmosphere and Volatile Evolution (MAVEN) probe. The time of greatest risk to the spacecraft is brief – about 20 minutes – when the widest part of the comet’s tail passes closest to the planet.

Will dust shed by the comet streak as meteors in the Martian sky on October 19? The rovers will be watching. Credit: NASA/JPL

One question I’m always asked is whether the Mars rovers are in any danger of dust-producing meteors in the comet’s wake. While the planet might get peppered with a meteor shower, its atmosphere is thick enough to incinerate cometary dust particles before they reach the surface, not unlike what happens during a typical meteor shower here on Earth. Rover cameras may be used to photograph the comet before the flyby and to capture meteors during the comet’s closest approach.

Despite concerns about dust, NASA knows a good opportunity when it sees one. In the days before and after the flyby, all three orbiters will conduct studies on the comet.

According to a recent NASA press release, instruments on MRO and Odyssey will examine the nucleus, coma and tail and possible effects on the Martian atmosphere:

Comet Siding Spring observed by the Spitzer Space Telescope in two wavelengths of infrared light in March 2014. The hint of blue-white corresponds to dust, red-orange to gas. Credit: NASA/JPL-Caltech/M. Kelley (Univ. Maryland)

“Odyssey will study thermal and spectral properties of the comet’s coma and tail. MRO will monitor Mars’ atmosphere for possible temperature increases and cloud formation, as well as changes in electron density at high altitudes and MAVEN will study gases coming off the comet’s nucleus as it’s warmed by the sun. The team anticipates this event will yield detailed views of the comet’s nucleus and potentially reveal its rotation rate and surface features.”

This is Comet Siding Spring’s first trip to the inner solar system. Expect exciting news as we peer up close at pristine ices and dust that have been locked in deep freeze since the time the planets formed.

For more information on the event, check out this NASA website devoted to the comet.

July 17, 2014December 23, 2015 by Bob King

Rosetta Zooms Toward an Extraordinary Comet

Comet 67P/C-G photographed on July 14, 2014 from a distance of approximately 12 000 km. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

I thought the photos earlier this week were amazing. This little movie, made of 36 ‘smoothed’ or interpolated images of Comet 67P/Churyumov-Gerasimenko, takes it to the next level, showing the comet’s complex shape even more clearly as Rosetta nudges ever closer to its target. Some have likened it to a duck, a boot and even a baby’s foot. The original photos used for the animation were more pixelated, but a technique known as “sub-sampling by interpolation” was used to smooth out the pixels for a more natural look. Be aware that because of processing, 67P C-G appears smoother than it might be. While the surface looks textured, including what appears to be a small crater atop the duck’s head, we have to be careful at this stage not to over-interpret – some of the details are artifacts.

Raw pixelated image of the comet (left) and after smoothing. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

No one knows yet how such an unusual shape formed in the first place. Possibly the comet is a ‘contact binary’ made of two separate comets or two parts of larger, shattered comet that stuck together during a low-velocity collision. This may have happened more 4 billion years ago when the icy building blocks of the planets and comets were numerous and collisions far more frequent than they are today. Contact binaries aren’t uncommon; we see them in asteroids and comets alike.

The Rosetta blog lists other intriguing scenarios:

* The comet may have once been a more spherical object but after many trips around the sun developed an asymmetrical shape from ice vaporization and outgassing.

* A near-catastrophic impact blasted away a huge chunk of comet ice.

* The strong gravitational pull experienced during a close pass of a large planet like Jupiter or Saturn may have pulled it into an irregular shape.

* A large outburst could have weakened a region on the comet’s surface that later crumbled away.

Detailed view of the likely contact binary asteroid 25143 Itokawa visited by the Japanese spacecraft Hayabusa in 2005. Credit: JAXA

“We will need to perform detailed analyses and modelling of the shape of the comet to determine how best we can fly around such a uniquely shaped body, taking into account flight control and astrodynamics, the science requirements of the mission, and the landing-related elements like landing site analysis and lander-to-orbiter visibility,” said Rosetta Mission Manager Fred Jansen. ” But with fewer than 10,000 km to go before the August 6th rendezvous, our open questions will soon be answered.”

In the meantime, keep the photos and movies coming. We can’t get enough.

July 12, 2014December 23, 2015 by Bob King

Comet Jacques Is Back! Joins Venus and Mercury at Dawn

Will you see it? Comet Jacques will pass about 3.5 degrees north of brilliant Venus tomorrow morning July 13. This map shows the sky facing northeast about 1 hour before sunrise. Stellarium

Comet C/2014 E2 Jacques has returned! Before it disappeared in the solar glow this spring, the comet reached magnitude +6, the naked eye limit. Now it’s back at dawn, rising higher each morning as it treks toward darker skies. Just days after its July 2 perihelion, the fuzzball will be in conjunction with the planet Venus tomorrow morning July 13. With Mercury nearby, you may have the chance to see this celestial ‘Rat Pack’ tucked within a 8° circle.

First photo of Comet Jacques on its return to the morning sky taken on July 7. Credit: Gerald Rhemann — First photo of Comet Jacques on its return to the morning sky taken on July 11. Two tails are visible – a short, dust tail pointing to the lower left of the coma and longer gas or ion tail to the right. Credit: Gerald Rhemann

While I can guarantee you’ll see Venus and probably Mercury (especially if you use binoculars), morning twilight and low altitude will undoubtedly make spotting Comet Jacques challenging. A 6-inch telescope might nail it. Look for a small, fuzzy cloud with a brighter core against the bluing sky. Patience is the sky observer’s most useful tool. It won’t be long before the comet’s westward motion combined with the seasonal drift of the stars will loft it into darkness again.

Use this map to follow Comet Jacques as it moves west across Taurus and Auriga over the next few weeks. Planet positions are shown for July 13 with stars to magnitude +6. Jacques' position is marked every 5 days. Source: Chris Mariott's SkyMap — Use this map to follow Comet Jacques as it moves west across Taurus and Auriga over the next few weeks. Planet positions are shown for July 13 with stars to magnitude +6. Jacques’ position is marked every 5 days. Click to enlarge. Source: Chris Mariott’s SkyMap

A week from now, when the moon’s slimmed to half, the comet will be nearly twice as high and should be easily visible in 50mm binoculars at the start of morning twilight.

Comet Jacques is expected to remain around magnitude +6 through the remainder of July into early August and then slowly fade. It will be well-placed in Perseus at the time of the Perseid meteor shower on Aug. 12-13. Closest approach to Earth occurs on August 29 at 52.4 million miles (84.3 million km). Good luck and let us know if you see it.

July 10, 2014December 23, 2015 by Bob King

Flaming Space Junk Makes Jaws Drop in Australia

Frame grab from a Youtube video of the brilliant meteor that flared over Australia overnight.

“It first looked like a plane with fire coming out of the tail.” — Aaron O.

“I have never seen anything like it. Big, bright and moving gently across sky – slower than a plane, not falling at all but moving across.” — Shannon H.

“Viewed from cockpit of aircraft at 37,000′. Was visible for two or three minutes.” — Landy T.

Flaming plane? Incandescent visitor from the asteroid belt? As the these comments from the AMS Fireball Log attest, the brilliant and s-l-o-w fireball that seared the sky over southeastern Australia tonight was probably one of the most spectacular displays of re-entering space junk witnessed in recent years.

Ted Molczan, citizen satellite tracker and frequent contributor to the amateur satellite watchers SeeSat-L site, notes that the timing and appearance almost certainly point to the decay or de-orbiting of the Russian Soyuz 2-1B rocket booster that launched the meteorological satellite Meteor M2 on July 8.

Meteor over New South Wales. Look closely near the end and you’ll see it disintegrate into small pieces.

The magnificent man-made meteor, weighing some 4,400 pounds (2,000 kg), was seen from Melbourne to Sydney across the states of Victoria and New South Wales around 10 p.m. Hundreds of people were stopped in their tracks. Most noticed how slowly the fireball traveled and how long it continue to burn on the way down.

Spacecraft that reenter from either orbital decay or controlled entry usually break up at altitudes between 45-52 miles (84-72 km) traveling around 17,500 mph (28,000 km/hour) . Compression and friction from the ever-thickening air cause the craft, or in this case, the rocket booster, to slow down and heat up to flaming incandescence just like a hunk of space rock arriving from the asteroid belt. In both cases, we see a brilliant meteor, however manmade debris.

Jan 21, 2001, a Delta 2 third stage, known as a PAM-D, reentered the atmosphere over the Middle East. The titanium motor casing, weighing about 70 kg, landed in Saudi Arabia about 240 km from the capital of Riyadh. Credit: NASA, Orbital Debris Program Office — A Delta 2 third stage, known as a PAM-D, reentered the atmosphere over the Middle East on Jan. 21, 2001. The titanium motor casing, weighing about 154 lbs. (70 kg), landed in Saudi Arabia about 150 miles from the capital of Riyadh. Credit: NASA, Orbital Debris Program Office

Occasional meteoroids break apart in the atmosphere and scatter meteorites just as pieces of occasional satellites, especially large, heavy craft, can survive the plunge and land intact – if a tad toasted. Whether anything remains of Russian rocket stage or where exactly it fell is still unknown. Here are a few more photos of successful space junk arrivals.

The only person to be hit by manmade space debris was Lottie Williams in 1997. She was unharmed. Credit: Tulsa World

Reportedly, only one person has been struck by satellite debris. In 1997 Lottie Williams of Tulsa, Oklahoma was hit on the shoulder while walking by a small, twisted piece of metal weighing as much as a crushed soda can. It was traced back to the tank of a Delta II rocket that launched a satellite in 1996. I suppose it’s only a matter of time before someone else gets hit, but the odds aren’t great. More likely, you’ll see what alarmed and delighted so many southeastern Australians Thursday night: a grand show of disintegration.

July 10, 2014December 23, 2015 by Bob King

Merging Giant Galaxies Sport ‘Blue Bling’ in New Hubble Pic

In this new Hubble image shows two galaxies (yellow, center) from the cluster SDSS J1531+3414 have been found to be merging into one and a "chain" of young stellar super-clusters are seen winding around the galaxies'?? nuclei. The galaxies are surrounded by an egg-shaped blue ring caused by the immense gravity of the cluster bending light from other galaxies beyond it. Credit: NASA/ESA/Grant Tremblay

On a summer night, high above our heads, where the Northern Crown and Herdsman meet, a titanic new galaxy is being born 4.5 billion light years away. You and I can’t see it, but astronomers using the Hubble Space Telescope released photographs today showing the merger of two enormous elliptical galaxies into a future heavyweight adorned with a dazzling string of super-sized star clusters.

The two giants, each about 330,000 light years across or more than three times the size of the Milky Way, are members of a large cluster of galaxies called SDSS J1531+3414. They’ve strayed into each other’s paths and are now helpless against the attractive force of gravity which pulls them ever closer.

A few examples of merging galaxies. NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University), K. Noll (STScI), and J. Westphal (Caltech)

Galactic mergers are violent events that strip gas, dust and stars away from the galaxies involved and can alter their appearances dramatically, forming large gaseous tails, glowing rings, and warped galactic disks. Stars on the other hand, like so many pinpoints in relatively empty space, pass by one another and rarely collide.

Elliptical galaxies get their name from their oval and spheroidal shapes. They lack the spiral arms, rich reserves of dust and gas and pizza-like flatness that give spiral galaxies like Andromeda and the Milky Way their multi-faceted character. Ellipticals, although incredibly rich in stars and globular clusters, generally appear featureless.

The differences between elliptical and spiral galaxies is easy to see. M87 at left and M74, both photographed with the Hubble Space Telescope. Credit: NASA/ESA — The differences between elliptical and spiral galaxies is easy to see. M87 at left and M74, both photographed with the Hubble Space Telescope. What look like stars around M87 are really globular star clusters. Credit: NASA/ESA

But these two monster ellipticals appear to be different. Unlike their gas-starved brothers and sisters, they’re rich enough in the stuff needed to induce star formation. Take a look at that string of blue blobs stretching across the center – astronomers call it a great example of ‘beads on a string’ star formation. The knotted rope of gaseous filaments with bright patches of new star clusters stems from the same physics which causes rain or water from a faucet to fall in droplets instead of streams. In the case of water, surface tension makes water ‘snap’ into individual droplets; with clouds of galactic gas, gravity is the great congealer.

Close up of the two elliptical galaxies undergoing a merger. The blue blobs are giant star clusters forming from gas colliding and collapsing into stars during the merger. Click for the scientific paper on the topic. Credit: NASA/ESA/Grant Tremblay — Close up of the two elliptical galaxies undergoing a merger. The blue blobs are giant star clusters forming from gas colliding and collapsing into stars during the merger. Click to read the scientific paper on the topic. Credit: NASA/ESA/Grant Tremblay

Nineteen compact clumps of young stars make up the length of this ‘string’, woven together with narrow filaments of hydrogen gas. The star formation spans 100,000 light years, about the size of our galaxy, the Milky Way. Astronomers still aren’t sure if the gas comes directly from the galaxies or has condensed like rain from X-ray-hot halos of gas surrounding both giants.

The blue arcs framing the merger have to do with the galaxy cluster’s enormous gravity, which warps the fabric of space like a lens, bending and focusing the light of more distant background galaxies into curvy strands of blue light. Each represents a highly distorted image of a real object.

Simulation of the Milky Way-Andromeda collision 4 billion years from now

Four billion years from now, Milky Way residents will experience a merger of our own when the Andromeda Galaxy, which has been heading our direction at 300,000 mph for millions of years, arrives on our doorstep. After a few do-si-dos the two galaxies will swallow one another up to form a much larger whirling dervish that some have already dubbed ‘Milkomeda’. Come that day, perhaps our combined galaxies will don a string a blue pearls too.

July 1, 2014December 23, 2015 by Bob King

Eureka! Kola Fireball Meteorites Found in Russia

Amateur astronomer and physics teacher Asko Aikkila managed to catch the Kola fireball on videotape in Kuusamo, Finland on April 19, 2014. The picture has been processed to enhance the details. Credit: Asko Aikkila / Finnish Fireball Network

A spectacular fireball that crackled across the sky near the Russia-Finnish border on April 19th this year left more than a bright flash. A team of meteor researchers from Finland, Russia and the Czech Republic scoured the predicted impact zone and recently discovered extraterrestrial booty.

A 120 gram fragment of the Annama meteorite. Streamlines of molten material heated during atmospheric entry can be seen on the crust. Credit: Jakub Haloda — A 120 gram fragment (left) of the Annama meteorite found on May 29, 2014. Streamlines of molten material heated during atmospheric entry can be seen on the crust. At right, a 48g fragment found on the following day. Credit: Jakub Haloda (left) and Grigory Yakovlev

There’s a lot of excitement about the fall because it’s the first time a meteorite was found based on coordinated all-sky camera network observations by the Ursa Finnish Fireball Network. Esko Lyytinen of the network with help from Jarmo Moilanen and Steinar Midtskogen reconstructed the meteoroid’s trajectory and dark flight (when it’s no longer luminous but yet to strike the ground) using simulations based on photos, videos and eyewitness reports.

Kola fireball meteors ended up near the Russian-Norwegian border. The fireball trajectory Esko Lyytinen of Ursa modeling of Heaven, watch videos on the findings and Murmansk. — Kola fireball meteors fell near the Russian-Norwegian border. The
fireball trajectory was modeled byEsko Lyytinen of the Ursa Finnish Fireball Network. Credit: Kuva Mikko Suominen / Celestia with info boxes translated by the author

The initial mass of meteoroid is estimated at about 1,100 pounds (500 kg). Much of that broke apart in the atmosphere and fell harmlessly as smaller stones. An international team of scientists mounted a 5-day expedition in late May after snow melt and before green up to uncover potential space rocks in the strewnfield, the name given to the oval-shaped zone where surviving fragments pepper the ground.

Russian amateur astronomer Nikolai Kruglikov discovered the first fragment of Annama meteorite on May 29, 2014 in the middle of a dirt road. Credit: Tomas Kohout — Russian amateur astronomer Nikolai Kruglikov discovered the first meteorite fragment in the middle of a dirt road. Credit: Tomas Kohout

On May 29, 2014, first 120 gram (4.2 ounce) meteorite fragment was found by Nikolai Kruglikov of Russia’s Ural Federal University on a forest road within the predicted impact area. The crew had been searching 1o hours a day when Kruglikov stopped the car to check out a suspect rock:

“Suddenly he started dancing and yelling. At first I could hardly believe it was a true discovery, but then I checked the composition of the rock using my instrument”, said Tomas Kohout, University of Helsinki physicist who participated in the hunt. The fusion-crusted stone displayed classic flow features from melting rock during high-speed atmospheric entry.

The very next day a second 48 gram crusted meteorite popped up. More are undoubtedly out there but the heavy brush numerous lakes make the finding challenging.

The crew is calling the new arrival the ‘Annama meteorite’ as it fell near the Annama River in Russia about 62 miles west of Murmansk. The Czech Geological Survey examined the space rocks and determined them to be ordinary chondrites representing the outer crust of an asteroid that got busted to bits in a long-ago collision. More than 95% of stony meteorites fall into this category including the 2013 fireball of Chelyabinsk, Russia.

Dashcam video of the brilliant fireball that dropped the ‘Annama meteorites’

“The Kola fireball is a rarity – it is one of only 22 cases where it was possible to determine its pre-impact solar system orbit before the impact with Earth’s atmosphere,” says Maria Gritsevich of the Finnish Geodetic Institute. “Knowing where the meteorite originates will help us better understand the formation and evolution of the solar system.” Congratulations Ursa!

June 26, 2014December 23, 2015 by Bob King

Ceres and Vesta Converge in the Sky on July 5: How to See It

Ceres and Vesta are converging in Virgo not far from Mars and Spica. On July 5, the duo will be just 10' apart and visible in the high power telescope field of view. Positions are shown every 5 days for 10 p.m. EDT and stars to magnitude +8.5. Created with Chris Marriott's SkyMap software

I bet you’ve forgotten. I almost did. In April, we reported that Ceres and Vesta, the largest and brightest asteroids respectively, were speeding through Virgo in tandem. Since then both have faded, but the best is yet to come. Converging closer by the day, on July 5, the two will make rare close pass of each other when they’ll be separated by just 10 minutes of arc or the thickness of a fat crescent moon.

Vesta (left) and Ceres. Vesta was photographed up close by the Dawn spacecraft from July 2011-Sept. 2012, while the best views we have to date of Ceres come from the Hubble Space Telescope. The bright white spot is still a mystery. Credit: NASA — Vesta (left) and Ceres. Vesta was photographed up close by the Dawn spacecraft from July 2011-Sept. 2012, while the best views we have to date of Ceres come from the Hubble Space Telescope. The bright white spot is still a mystery. NASA will plunk Dawn into orbit around Ceres next February. Credit: NASA

Both asteroids are still within range of ordinary 35mm and larger binoculars; Vesta is easy at magnitude +7 while Ceres still manages a respectable +8.3. From an outer suburban or rural site, you can watch them draw together in the coming two weeks as if on a collision course. They won’t crash anytime soon. We merely see the two bodies along the same line of sight. Vesta’s closer to Earth at 164 million miles (264 million km) and moves more quickly across the sky compared to Ceres, which orbits 51 million miles (82 million km) farther out.

Ceres and Vesta are happily near an easy naked eye star, Zeta Virginis, which forms an isosceles triangle right now with Mars and Spica. The map shows the sky around 10 p.m. local time facing southwest. Stellarium — Ceres and Vesta lie near an easy naked eye star, Zeta Virginis, which forms an isosceles triangle right now with Mars and Spica. The map shows the sky around 10 p.m. local time tonight facing southwest. Stellarium

Right now the two asteroids are little more than a moon diameter apart not far from the 3rd magnitude star Zeta Virginis. Happily, nearby Mars and Spica make excellent guides for finding Zeta. Once you’re there, use binoculars and the more detailed map to track down Ceres and Vesta.

Virgo will be busy Saturday night July 5, 2014 when the waxing moon is in close conjunction with Mars with Ceres and Vesta at their closest. Stellarium — Virgo will be busy Saturday night July 5, 2014 when the waxing moon passes about 1/2 degree from Mars as Ceres and Vesta squeeze closest. Stellarium

In early July they’ll look like a wide double star in binoculars and easily fit in the same high power telescopic view. Vesta has always looked pale yellow to my eye. Will its color differ from Ceres? Sitting side by side it will be easier than ever to compare them. Vesta is a stony asteroid with a surface composed of solidified (and meteoroid-battered) lavas; Ceres is darker and covered with a mix of water ice and carbonaceous materials.

On the night of closest approach, it may be difficult to spot dimmer Ceres in binoculars. By coincidence, the 8-day-old moon will be very close to the planet Mars and brighten up the neighborhood. We’ll report more on that event in a future article.

With so much happening the evening of July 5, let’s hope for a good round of clear skies.