Astronomy Archives

September 12, 2013April 26, 2016 by David Dickinson

Spotting Juno: NASA’s Jupiter-bound Spacecraft Gets a Boost from Earth on October 9th, 2013

An artist's conception of Juno's October 9th flyby of the Earth. (Credit: NASA/JPL -Caltech).

Psst! Live in South Africa and read Universe Today? Then you might just get a peak at the Juno spacecraft as it receives a boost from our fair planet on the evening of October 9^th, 2013.

Launched from Cape Canaveral Air Force Station on August 5^th, 2011 atop an Atlas 5 rocket in a 551 configuration, Jupiter-bound Juno is approaching the Earth from interior to its orbit over the next month. Its closest approach to the Earth during its October 9^th flyby will occur at 19:21 Universal Time (UT) which is 3:21 PM Eastern Daylight Saving Time. The spacecraft will pass 559 kilometres over the South Atlantic to a point 200 kilometres off of the southeastern coast of South Africa at latitude -34.2° south & longitude 34° east.

For context, this is just about 25% higher than the International Space Station orbits at an average of 415 kilometres above the Earth. The ISS is 108.5 metres across on its longest dimension, and we wouldn’t be surprised if Juno were a naked eye object for well placed observers watching from a dark sky site around Cape Town, South Africa. Especially if one of its three enormous 8.9 metre long solar panels were to catch the Sun and flare Iridium-style!

Two minutes before closest approach, Juno will experience the only eclipse of its mission, passing into the umbra of Earth’s shadow for about 20 minutes. Chris Peat at Heavens-Above also told Universe Today that observers in India are also well-placed to catch sight of Juno with binoculars after it exits the Earth’s shadow.

Juno passed its half-way mark to Jupiter last month on August 12^th when the “odometer clicked over” to 9.464 astronomical units. Juno will enter orbit around Jupiter on July 4^th, 2016. Juno will be the second spacecraft after Galileo to permanently orbit the largest planet in our solar system.

The passage of Juno through the Earth's shadow on October 9th, 2013. (Credit and Copyright: Heavens-Above, used with permission). — The passage of Juno through the Earth’s shadow on October 9th, 2013. (Credit and Copyright: Heavens-Above, used with permission).

Catching a flyby of Juno will be a unique event. Unfortunately, the bulk of the world will miss out, although you can always vicariously fly along with Juno with Eyes on the Solar System. Juno is currently moving about 7 km/s relative to the Earth, and will move slightly faster than the ISS in its apparent motion across the sky from west to east before hitting Earth’s shadow. This slingshot will give Juno a 70% boost in velocity to just under 12km/s relative to Earth, just slower than Pioneer 10’s current motion relative to the Sun of 12.1km/s.

At that speed, Juno will be back out past the Moon in about 10 hours after flyby. There’s a chance that dedicated imagers based along North American longitudes could still spy Juno later that evening.

Juno approaches the Earth from the direction of the constellation Libra and will recede from us in the direction of the constellation Perseus on the night of October 9^th.

The ground track covered by Juno as it passes by the Earth. (Credit & Copyright: Heavens-Above, used with permission).

There’s also a precedent for spotting such flybys previous. On August 18^th, 1999, NASA’s Cassini spacecraft made a flyby of the Earth at 1,171 kilometres distant, witnessed by observers based in the eastern Pacific region. Back then, a fuss had been raised about the dangers that a plutonium-powered spacecraft might posed to the Earth, should a mis-calculation occur. No such worries surround Juno, as it will be the first solar-powered spacecraft to visit the outer solar system.

And NASA wants to hear about your efforts to find and track Juno during its historic 2013 flyby of the Earth. JPL Horizons lists an ephemeris for the Juno spacecraft, which is invaluable for dedicated sky hunters. You can tailor the output for your precise location, then aim a telescope at low power at the predicted right ascension and declination at the proper time, and watch. Precise timing is crucial; I use WWV shortwave radio broadcasting out of Fort Collins, Colorado for ultra-precise time when in the field.

As of this writing, there are no plans to broadcast the passage of Juno live, though I wouldn’t be surprised if someone like Slooh decides to undertake the effort. Also, keep an eye on Heavens-Above, as they may post sighting opportunities as well. We’ll pass ‘em along if they surface!

Late Breaking: And surface they have… a page dedicated to Juno’s flyby of Earth is now up on Heavens-Above.

Juno is slated to perform a one year science mission studying the gravity and magnetic field of Jupiter as well as the polar magnetosphere of the giant planet. During this time, Juno will make 33 orbits of Jupiter to complete its primary science mission. Juno will study the environs of Jupiter from a highly inclined polar orbit, which will unfortunately preclude study of its large moons. Intense radiation is a primary hazard for spacecraft orbiting Jupiter, especially one equipped with solar panels. Juno’s core is shielded by one centimetre thick titanium walls, and it must thread Jupiter’s radiation belts while passing no closer than 4,300 kilometres above the poles on each pass. One run-in with the Io Plasma Torus would do the spacecraft in. Like Galileo, Juno will be purposely deorbited into Jupiter after its primary mission is completed in October 2017.

If you live in the right location, be sure to check out Juno as it visits the Earth, one last time. We’ll keep you posted on any live broadcasts or any further info on sighting opportunities as October 9^th draws near!

– Got pics of Juno on its flyby of the Earth? Send ’em in to Universe Today!

– You can also follow the mission on Twitter as @NASAJuno.

September 12, 2013April 26, 2016 by Elizabeth Howell

Rainbow Pictures Of Milky Way Show Off Galaxy’s Structure

A colorful view of the Milky Way based on a new 3-D structure created by astronomers. "Due to our position within the disk it is difficult to identify the detailed structure of the inner galaxy," the Max Planck Institute for Extraterrestrial Physics said in a statement. Credit: MPE

Thanks to a new analysis of pictures obtained by a telescope in Chile, astronomers are gaining a better understanding of how the Milky Way formed and how our home galaxy has changed over the years.

Here’s how the project worked:

– The European Southern Observatory’s Visible and Infrared Survey Telescope for Astronomy (VISTA) 4.1-meter telescope took near-infrared pictures of the bulge of the Milky Way during the Variables in the Via Lactea public survey.

– Using the public data, scientists at the Max Planck Institute for Extraterrestrial Physics (MPE) created a three-dimensional star map of the inner regions of the Milky Way.

– Their findings were that the bulge in the center is shaped like a box or a peanut, with characteristics such as an “elongated bar”. It’s the first time such an accurate 3-D map of the inner universe was constructed, the science team said.

“This indicates that the Milky Way was originally a pure disk of stars, which then formed a thin bar, before buckling into the box/peanut shape seen today,” MPE stated. “The new map can be used for more detailed studies of the dynamics and evolution of our Milky Way.”

Among other conclusions, this helps confirm the fairly recent finding that the Milky Way is a barred spiral galaxy, rather than just a spiral galaxy.

More pictures and details are available at the Max Planck Institute for Extraterrestrial Physics’ website.

September 10, 2013December 23, 2015 by Bob King

New Comet Discovered: Lovejoy Will Add to “Comet Lineup” in Winter Skies

New Comet Lovejoy starts out slow but quickly gains speed as it crosses from near Orion in mid-September to Ursa Major in November, when it will be closest to Earth. Created with Chris Marriott's SkyMap software

Move over Comet ISON. You’ve got company. Australian amateur astronomer Terry Lovejoy, discoverer of three previous comets, including the famous, long-tailed sungrazer C/2011 W3 (Lovejoy), just added a 4th to his tally.

This new comet will add to a lineup of comets that should grace early November skies in the northern hemisphere: Comets ISON, Encke and now the new Lovejoy.

Comet C/2013 R1 Lovejoy photographed on Sept. 10. The comet is visible in larger amateur telescopes in September but may brighten to small scope visibility in November. Credit: Michael Jaeger — Comet C/2013 R1 Lovejoy photographed on Sept. 10. The comet is visible in larger amateur telescopes in September but may brighten to small scope visibility in November. Streak at right is a geostationary satellite. Credit: Michael Jaeger

The discovery of C/2013 R1 Lovejoy was announced on Sept. 9 after two nights of photographic observations by Lovejoy with an 8-inch (20 cm) Schmidt-Cassegrain reflector. When nabbed, the comet was a faint midge of about 14.5 magnitude crossing the border between Orion and Monoceros. Subsequent observations by other amateur astronomers peg it a bit brighter at 14.0 with a small, condensed coma.

*Comet Lovejoy has a small, condensed coma (head) about 30 arc seconds across with a faint, short tail in this photo made on Sept. 8. Credit: Ernesto Guido and Nick Howes*

Right now you’ll need a hefty telescope to catch a glimpse of Lovejoy’s latest, but come November the comet will glow at around 8th magnitude, making it a perfect target for smaller telescopes. At closest approach on the Nov. 23, Lovejoy will pass 38.1 million miles (61.3 million km) from Earth while sailing across the Big Dipper at a quick pace.

The comet is a faint 14th magnitude object just east of Orion's Belt in the dim constellation Monoceros the Unicorn. The map shows its position tomorrow morning Sept. 11 just before the start of morning twilight. Stellarium — The comet is a faint 14th magnitude object just east of Orion’s Belt in the dim constellation Monoceros the Unicorn. The map shows its position tomorrow morning Sept. 11 just before the start of morning twilight. Stellarium

Mid to late November is also the time when Comet ISON, the current focus of much professional and amateur observation, will be at its brightest in the morning sky at around magnitude 2-3. Get ready for some busy nights at the telescope!

A graph showing the comet's predicted magnitude (subject to change) in red versus the comet's elongation or distance from the sun. You can see that it will up in a dark sky for a long time especially around the time when it's brightest. Credit: Ernesto Guido & Nick Howes — A graph showing the comet’s predicted magnitude (subject to change) in red versus the comet’s elongation or angular distance from the sun. You can see that it will up in a dark sky for a long time including around the time when it’s brightest. Credit: Ernesto Guido & Nick Howes

C/2013 R1 will whip by the sun on Christmas Day at a distance of 81 million miles (130.3 million km) and then return back to the deeps from whence it came.

The charts here give you a general idea of its location and path over the next couple months. As the comet crosses into small-scope territory in early November, I’ll provide maps for you to find it.

A graphic created by Stuart Atkinson showing the comet and planetary lineup that should be in the skies on November 9, 2013.

And as Stuart Atkinson noted on his website, Cumbrian Sky a great lineup should be in the northern hemisphere skies on November 9, 2013. From the left, Comet Encke will be magnitude 6, ISON should be at about magnitude 6 or 7; then Mars, followed by the new Comet Lovejoy, which will be still very faint at around magnitude 9, topped off by a bright Jupiter. The comets will not likely be of naked eye visibility, but this should be a great chance for astrophotographer to capture this lineup!

Comet Lovejoy is approaching the plane of the planets from down under. The diagram shows the comet's position today. Like many comets, Lovejoy's orbit is steeply inclined - in this case 62 degrees. Credit: NASA — Comet Lovejoy is approaching the plane of the planets from “down under” (lower right). The diagram shows the comet’s position today. Like many comets, Lovejoy’s orbit is steeply inclined – in this case 62 degrees. Credit: NASA

Welcome to an exciting time for comet lovers, and congratulations Terry on another great discovery!

September 10, 2013December 23, 2015 by Jason Major

“Oddball” Asteroid is Really a Comet

Spitzer image of an asteroid's surprise coma and tail (NASA/JPL-Caltech/DLR/NAU)

It’s a case of mistaken identity: a near-Earth asteroid with a peculiar orbit turns out not to be an asteroid at all, but a comet… and not some Sun-dried burnt-out briquette either but an actual active comet containing rock and dust as well as CO2 and water ice. The discovery not only realizes the true nature of one particular NEO but could also shed new light on the origins of water here on Earth.

JPL Near-Earth Object database map of 3552 Don Quixote's orbit — JPL Near-Earth Object database map of 3552 Don Quixote’s orbit

Designated 3552 Don Quixote, the 19-km-wide object is the third largest near-Earth object — mostly rocky asteroids that orbit the Sun in the vicinity of Earth.

According to the IAU, an asteroid is coined a near-Earth object (NEO) when its trajectory brings it within 1.3 AU from the Sun and within 0.3 AU of Earth’s orbit.

About 5 percent of near-Earth asteroids are thought to actually be dead comets. Today an international team including Joshua Emery, assistant professor of earth and planetary sciences at the University of Tennessee, have announced that Don Quixote is neither.

an asteroid is coined a Near Earth Asteroid (NEA) when its trajectory brings it within 1.3 AU from the Sun and hence within 0.3 AU of the Earth's orbit. — *An asteroid is coined a near-Earth object (NEO) when its trajectory brings it within 1.3 AU from the Sun and within 0.3 AU of Earth’s orbit. (IAU)*

“Don Quixote has always been recognized as an oddball,” said Emery. “Its orbit brings it close to Earth, but also takes it way out past Jupiter. Such a vast orbit is similar to a comet’s, not an asteroid’s, which tend to be more circular — so people thought it was one that had shed all its ice deposits.”

Using the NASA/JPL Spitzer Space Telescope, the team — led by Michael Mommert of Northern Arizona University — reexamined images of Don Quixote from 2009 when it was at perihelion and found it had a coma and a faint tail.

Emery also reexamined images from 2004, when Quixote was at its farthest distance from the Sun, and determined that the surface is composed of silicate dust, which is similar to comet dust. He also determined that Don Quixote did not have a coma or tail at this distance, which is common for comets because they need the sun’s radiation to form the coma and the sun’s charged particles to form the tail.

The researchers also confirmed Don Quixote’s size and the low, comet-like reflectivity of its surface.

“The power of the Spitzer telescope allowed us to spot the coma and tail, which was not possible using optical telescopes on the ground,” said Emery. “We now think this body contains a lot of ice, including carbon dioxide and/or carbon monoxide ice, rather than just being rocky.”

This discovery implies that carbon dioxide and water ice might be present within other near-Earth asteroids and may also have implications for the origins of water on Earth, as comets are thought to be the source of at least some of it.

The amount of water on Don Quixote is estimated to be about 100 billion tons — roughly the same amount in Lake Tahoe.

“Our observations clearly show the presence of a coma and a tail which we identify as molecular line emission from CO2 and thermal emission from dust. Our discovery indicates that more NEOs may harbor volatiles than previously expected.”

– Mommert et al., “Cometary Activity in Near–Earth Asteroid (3552) Don Quixote “

The findings were presented Sept. 10 at the European Planetary Science Congress 2013 in London.

Source: University of Tennessee press release

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3552 Quixote isn’t the only asteroid found to exhibit comet-like behavior either — check out Elizabeth Howell’s recent article, “Asteroid vs. Comet: What the Heck is 3200 Phaethon?” for a look at another NEA with cometary aspirations.

September 10, 2013December 23, 2015 by Elizabeth Howell

How Do You Find The Signs of Life On Alien Planets?

Artist's conception of the alien planet system orbiting Gliese 581. Credit: ESO/L. Calçada

One big challenge in astronomy is everything is so darn far away. This makes it hard to see the signs of life in planets, which are usually but tiny dots of light using the telescope technology we have today.

There are signs in Earth’s atmosphere that life is on the surface — methane from microbes, for example — and already scientists have years of research concerning ideas to find “biomarkers” on other planets. A new model focuses on a theoretical Earth-sized planet orbiting a red dwarf star, where it is believed biomarkers would be easier to find because these stars are smaller and fainter than that of the sun.

“We developed computer models of exoplanets which simulate the abundances of different biomarkers and the way they affect the light shining through a planet’s atmosphere,” stated Lee Grenfell, who is with the German Aerospace Center (DLR) institute of planetary science.

Preliminary work has already been done to find chemicals in the planet’s atmosphere (by looking at how they affect light that pass through the chemicals) particularly on large exoplanets that are close to their star (sometimes called “hot Jupiters“). Signs of life would be found through a similar process, but would be much fainter.

Artists Impression of a Red Dwarf (courtesy NASA) — Artist’s impression of a red dwarf (courtesy NASA)

The research team constructed a model of a planet similar to Earth, at different orbits and distances from a red dwarf stars. Their work shows a sort of “Goldilocks” effect (or, a condition that is “just right”) to find ozone when the ultraviolet radiation falls into the medium of a given range. If it is too high, the UV heats the middle atmosphere and obliterates the biomarker signal. Too low UV makes the signal very hard to find.

“We find that variations in the UV emissions of red-dwarf stars have a potentially large impact on atmospheric biosignatures in simulations of Earth-like exoplanets. Our work emphasizes the need for future missions to characterise the UV emissions of this type of star,” said Grenfell.

The research has plenty of limitations, he added. We don’t know what alien life would look like, we don’t know if planets near red dwarfs are a good place to search, and even if we found a signal that looked like life, it could have come from another process. Still, Grenfell’s team expects the model is a good basis on which to continue asking the question: is life really out there?

The research has been submitted to the journal Planetary and Space Science.

Source: European Planetary Science Conference

September 10, 2013April 26, 2016 by Elizabeth Howell

Asteroid Vs. Comet: What The Heck Is 3200 Phaethon?

A very zoomed-in image of Phaethon from NASA's STEREO spacecraft, showing a comet-like extension. Credit: Jewitt, Li, Agarwal /NASA/STEREO

Sometimes, putting things into categories difficult. Witness how many members of the general public are still unhappy that Pluto was reclassified as a dwarf planet, a decision made by the International Astronomical Union more than seven years ago.

And now we have 3200 Phaethon, an asteroid that is actually behaving like a comet. Scientists found dust that is streaming from this space rock as it gets close to the sun — similarly to how ices melt and form a tail as comets zoom by our closest stellar neighbor.

Phaethon’s orbit puts it in the same originating region as other asteroids (between Mars and Jupiter), but its dust stream is much closer to actions performed by a comet — an object that typically comes from an icy region way beyond Neptune. So far, therefore, the research team is calling Phaethon a “rock comet.” And after first proposing a theory a few years ago, they now have observations as to what may be going on.

Phaethon is not only an asteroid, but also a source of a prominent meteor shower called the Geminids. This shower happens every year around December when the Earth plows into the cloud of debris that Phaethon leaves in its wake. Astronomers have known about the Geminids’ source for a generation, but for decades could not catch the asteroid in the act of shedding its stuff.

That finally came with images of NASA’s twin sun-gazing Solar TErrestrial RElations Observatory (STEREO) spacecraft that were taken between 2009 and 2012. The researchers saw a “comet-like tail” extending from the 3.1-mile (five kilometer) asteroid. “The tail gives incontrovertible evidence that Phaethon ejects dust,” stated David Jewitt, an astronomer at the University of California, Los Angeles who led the research. “That still leaves the question: why?”

Time lapse-photo showing geminids over Pendleton, OR. Credit: Thomas W. Earle

The answer lies in just how close Phaethon whizzes past the sun. At perihelion, its closest approach to the sun, it only appears eight degrees (16 solar diameters) away from the sun in Earth’s sky. This close distance makes it all but impossible to study the asteroid without special equipment, which is why STEREO came in so handy.

When Phaethon reaches its closest approach of 0.14 Earth-sun distances, surface temperatures rise above an estimated 1,300 degrees Fahrenheit (700 degrees Celsius). It’ s way too hot for ice, as what happens with a comet. In fact, it’s probably hot enough to make the rocks crack and break apart. The researchers publicly hypothesized this was happening at least as far back as 2010, but this finding provided more evidence to support that theory.

“The team believes that thermal fracture and desiccation fracture (formed like mud cracks in a dry lake bed) may be launching small dust particles that are then picked up by sunlight and pushed into the tail,” a statement from the research team read.

“While this is the first time that thermal disintegration has been found to play an important role in the solar system,” they added, “astronomers have already detected unexpected amounts of hot dust around some nearby stars that might have been similarly produced.”

The results were presented at the European Planetary Science Congress on Tuesday. By the way, STEREO also caught Mercury behaving somewhat like a comet in results released in 2010, although that find was related to the planet’s escaping sodium atmosphere.

Read more about the research in the June 26 issue of Astrophysical Letters. A preprint version is also available on Arxiv.

Source: European Planetary Science Congress

September 9, 2013April 26, 2016 by David Dickinson

Huge Asteroid 324 Bamberga Makes a Return Visit to Earth’s Neighborhood on Friday the 13th

This week offers a fine chance to catch sight of a unique asteroid.

324 Bamberga reaches opposition this week in the constellation Pisces on (friggatriskaidekaphobics take note) Friday the 13^th at 7AM EDT/11:00 Universal Time.

About 230 kilometres in size, 324 Bamberga reaches 0.81 astronomical units from the Earth this week. No other asteroid so large gets so close.

Discovered on February 25^th, 1892 by Johann Palisa, 324 Bamberga only reaches a favorable opposition once every 22 years.

Shining at magnitude +8.1, 324 Bamberga is also one of the highest numbered asteroids visible with binoculars. Earth-crossing asteroids 433 Eros, which made a close pass last year, and 4179 Toutatis are two of the very few asteroids that possess a larger number designations that can regularly reach +10^th magnitude.

Look east in mid-September about an hour after sunset. The inset covers the region that 324 Bamberga is currently traversing in the introductory graphic. (Created by the author using Stellarium).

So, why did it take so long for 324 Bamberga to be uncovered? One factor is its high orbital eccentricity of 0.34. This means that most of the oppositions of the asteroid aren’t favorable. 324 Bamberga orbits the Sun once every 4.395 years and only comes around to an opposition that lands near perihelion once every 22 Earth years. Perihelion this year occurs only 45 days after opposition on October 27^th.

The resonance between 324 Bamberga and Earth is nearly five Earth orbits for every one circuit of the Sun for the asteroid and is offset by only 9 days, meaning that the 22 year window to see the asteroid will actually become less favorable in centuries to come. 324 Bamberga made its last favorable appearance on September 15^th, 1991 and won’t surpass +10^th magnitude again until September 2035.

Observing asteroids requires patience and the ability to pick out a slowly moving object amidst the starry background. 324 Bamberga spends September west of the circlet of Pisces, drifting two degrees a week, or just over 17’ a day, to cross over into the constellation Pegasus in early October.

324 Bamberga will be moving too slow to pick up any motion in real time, but you can spy it by either sketching the field on successive nights or photographing the region and noting if the asteroid can be seen changing position against the background of fixed stars. Start hunting for 324 Bamberga tonight, as the Full Harvest Moon will be visiting Pisces later next week on the 19^th.

324 Bamberga is also unique as the brightest C-type asteroid that is ever visible from Earth. The runner up in this category is asteroid 10 Hygiea, which can shine a full magnitude fainter at opposition.

It’s also remarkable that Palisa actually managed to discover 324 Bamberga while it was at 12^th magnitude! Palisa was one of the most prolific visual hunters of asteroids ever, discovering 121 asteroids from 1874 to 1923. He accomplished this feat first with the use of a 6” refractor while based at the Austrian Naval Observatory in Pola (now the Croatian town of Pula) and later using the Vienna observatory’s 27” inch refractor.

The Great Refractor of the University of Vienna used to discover asteroid 324 Bamberga. (Credit: Prof. Franz Kerschbaum, Wikimedia Commons image under an Attribution-Share Alike 3.0 Unported license).

324 Bamberga itself takes its name from the town of Bamberg in Bavaria, the site of the 1896 meeting of the Astronomische Gesellschraft.

An occultation of a star by 324 Bamberga on December 8^th,1987 allowed astronomers to pin down its approximate size. Searches have also been carried out during occultations for any possible moons of this asteroid, though thus far, none have been discovered.

It’s interesting to note that 324 Bamberga will also actually occult the star 2UCAC 3361042 tonight in the early morning hours at 8:59-9:10 UT for observers spanning a path from Florida to Oregon. The magnitude drop will, however, be very slight, as the star is actually 3 full magnitudes fainter than the asteroid itself. Dave Gee caught a fine occultation of a 7.4 magnitude star in the constellation Corvus by 324 Bamberga in 2007.

There’s also something special about this time of year and the region that 324 Bamberga is crossing. More visual discoveries of asteroids have been historically made in the month of September than any other calendar month. In fact, 344 of the first 1,940 numbered asteroids were found in September, more than twice the average. Palisa’s own track record bears this out, though 324 Bamberga was discovered in February.

One of the primary reasons for a September surge in discoveries is viewing direction. Astronomers of yore typically hunted for asteroids approaching opposition in the anti-sunward direction, which in September lies in the relatively star poor fields of Pisces. In December and June —the months with the lowest numbers of visual discoveries at only 75 and 65 for the “first 1,940” respectively —the anti-sunward point lies in the star-rich regions of Sagittarius and Gemini. And by the way, the meteor that exploded over the city of Chelyabinsk on February 15^th was sneaking up on the Earth from the sunward direction.

Be sure to catch a glimpse of this unique asteroid through either binoculars or a telescope over the coming weeks. The next chance to observe 324 Bamberga won’t roll around again until September 2035… it’ll be great to compare notes of the 2013 apparition on that far off date!

September 9, 2013April 26, 2016 by Elizabeth Howell

Researchers Say ExoMars Could Detect Bacteria on Mars — Past or Present

An artist's conception of the European Space Agency's ExoMars rover, scheduled to launch in 2018. Credit: ESA

Signs of life on the Martian surface would still be visible even after bacteria were zapped with a potentially fatal dose of radiation, according to new research — if life ever existed there, of course.

Using “model” bacteria expected to resemble what microbes could look like on the Red Planet, the research team used a Raman spectrometer — an instrument type that the ExoMars rover will carry in 2018 — to see how the signal from the bacteria change as they get exposed to more and more radiation.

The bottom line is the study authors believe the European Space Agency rover’s instrument would be capable of seeing bacteria on Mars — from the past or the present — if the bacteria were there in the first place.

Readings from the NASA Mars Curiosity rover recently found that humans on the surface of Mars would have a higher risk of cancer due to the increased radiation level on the surface. Mars does not have a global magnetic field to deflect radiation from solar flares, nor a thick atmosphere to shelter the surface.

The new study still found the signature of life in these model microbes at 15,000 Gray of radiation, which is thousands of times higher than the radiation dose that would kill a human. At 10 times more, or 150,000 Gray, the signature is erased.

ExoMars 2016 Mission to the Red Planet. It consists of two spacecraft - the Trace Gas Orbiter (TGO) and the Entry, Descent and Landing Demonstrator Module (EDM) which will land. Credit: ESA — ExoMars 2016 Mission to the Red Planet. It consists of two spacecraft – the Trace Gas Orbiter (TGO) and the Entry, Descent and Landing Demonstrator Module (EDM) which will land. Credit: ESA

“What we’ve been able to show is how the tell-tale signature of life is erased as the energetic radiation smashes up the cells’ molecules,” stated Lewis Dartnell, an astrobiology researcher at the University of Leicester who led the study.

Specifically, the spectrometer detected carotenoid molecules, which can be used to protect a microorganism against difficult conditions in the environment. The research teams stated that these cartenoids have been proposed as “good biosignatures of life” on Mars.

This image shows a river that sprang from a past glacier from an unnamed crater in Mars’ middle latitudes. Credit: NASA/JPL/MSSS

“In this study we’ve used a bacterium with unrivaled resistance to radiation as a model for the type of bacteria we might find signs of on Mars. What we want to explore now is how other signs of life might be distorted or degraded by irradiation,” Dartnell added. “This is crucial work for understanding what signs to look for to detect remnants of ancient life on Mars that has been exposed to the bombardment of cosmic radiation for very long periods of time.”

No one is sure if Mars has life right now on its surface, or ever did in the past. The Mars Curiosity rover is equipped to look at past environmental conditions on the planet, but is not designed to look for life itself.

Many scientists believe flowing water existed on the planet, though, based on rock findings from three NASA rovers and the appearance of channels, streams and perhaps even oceans as spotted by orbiting satellites. Some scientists say the atmosphere of Mars was much thicker in the past, but it then dissipated for reasons that are still being investigated. Water, however, does not necessarily point to life.

The research was presented at the European Planetary Science Congress on Monday. Universe Today has reached out to Dartnell to see if the work is peer-reviewed. His website lists several published research articles he wrote on similar topics.

Edit: Dartnell says that research was published in Analytical and Bioanalytical Chemistry in 2012, and you can read the paper here.

Source: European Planetary Science Congress

September 5, 2013December 23, 2015 by Jason Major

Supermassive Black Holes Keep Galaxies From Getting Bigger

Radio telescope image of the galaxy 4C12.50, nearly 1.5 billion light-years from Earth. Inset shows detail of location at end of superfast jet of particles, where a massive gas cloud (yellow-orange) is being pushed by the jet. (Credit: Morganti et al., NRAO/AUI/NSF)

It’s long been a mystery for astronomers: why aren’t galaxies bigger? What regulates their rates of star formation and keeps them from just becoming even more chock-full-of-stars than they already are? Now, using a worldwide network of radio telescopes, researchers have observed one of the processes that was on the short list of suspects: one supermassive black hole’s jets are plowing huge amounts of potential star-stuff clear out of its galaxy.

Astronomers have theorized that many galaxies should be more massive and have more stars than is actually the case. Scientists proposed two major mechanisms that would slow or halt the process of mass growth and star formation — violent stellar winds from bursts of star formation and pushback from the jets powered by the galaxy’s central, supermassive black hole.

“With the finely-detailed images provided by an intercontinental combination of radio telescopes, we have been able to see massive clumps of cold gas being pushed away from the galaxy’s center by the black-hole-powered jets,” said Raffaella Morganti, of the Netherlands Institute for Radio Astronomy and the University of Groningen.

The scientists studied a galaxy called 4C12.50, nearly 1.5 billion light-years from Earth. They chose this galaxy because it is at a stage where the black-hole “engine” that produces the jets is just turning on. As the black hole, a concentration of mass so dense that not even light can escape, pulls material toward it, the material forms a swirling disk surrounding the black hole. Processes in the disk tap the tremendous gravitational energy of the black hole to propel material outward from the poles of the disk.

NGC 253, aka the Sculptor Galaxy, is also blowing out gas but as the result of star formation (Image: T.A. Rector/University of Alaska Anchorage, T. Abbott and NOAO/AURA/NSF)

At the ends of both jets, the researchers found clumps of hydrogen gas moving outward from the galaxy at 1,000 kilometers per second. One of the clouds has much as 16,000 times the mass of the Sun, while the other contains 140,000 times the mass of the Sun.

The larger cloud, the scientists said, is roughly 160 by 190 light-years in size.

“This is the most definitive evidence yet for an interaction between the swift-moving jet of such a galaxy and a dense interstellar gas cloud,” Morganti said. “We believe we are seeing in action the process by which an active, central engine can remove gas — the raw material for star formation — from a young galaxy,” she added.

The researchers published their findings in the September 6 issue of the journal Science.

Source: NRAO press release

September 5, 2013April 26, 2016 by David Dickinson

See Venus and the Moon Together in the Sky on September 8

A close conjunction of Venus and the crescent Moon as seen on February 27th, 2009. (Photo by author).

Sky watchers worldwide are in for a treat Sunday evening September 8, 2013 as the waxing crescent Moon passes near the dazzling planet Venus. And for a select few, the Moon will actually pass in front of Venus, in what is known as an occultation.

The action has already started this week, as the Moon reached New phase earlier today at 7:36 AM EDT/11:36 UT. The appearance of the slim crescent Moon nearest to the September equinox marks the start of the Jewish New Year with the celebration of Rosh Hashanah, which this year began as early as it possibly can at sundown on September 4^th. As per tradition, Rosh Hashanah formally begins when the sky is dark enough for three stars to be seen. The convention established by Hillel II in 363 A.D. uses the mean motion of the Moon to fix the start dates of the Jewish luni-solar calendar, which means that occasionally Rosh Hashanah can start a day early. This also occurred in 2002.

The New Moon has also been historically an opportune time for nighttime military operations to commence —Desert Storm in 1991 and the raid against Bin Laden in 2011 were both conducted under the darkness afforded by the absence of moonlight around a New Moon. It’s yet to be seen if planners looking to conduct airstrikes on Syria are planning on taking advantage of the same conditions to begin operations soon.

Tonight, you can see the +1^st magnitude star Spica less than two degrees away from -4^th magnitude Venus. This places Venus at 100 times brighter than Spica and visible before sunset if you know exactly where to look for it.

The brightest star in the constellation Virgo, Spica is 260 light years distant and on the short list of nearby stars that will eventually go supernova. Fortunately for us, Spica is well outside of the ~100 light year radius “kill zone”.

You might just be able to spy the Moon and the -1st magnitude planet Mercury low to the west at dusk for the first time for this lunation tonight or (more likely) Friday night. This is also a great time to check out LADEE’s future home as it departs for lunar orbit from Wallops Island in Virginia on Friday night.

Hey, LADEE sitting on the pad atop its Minotaur V rocket with the slim crescent Moon in the background at dusk Friday night would be a great money shot, I’m just sayin’…

This weekend will see the Moon increase in illumination and elevation above the western horizon each evening until Spica, Venus, and the waxing crescent Moon fit within a four degree circle on Sunday night. The Moon will be 12% illuminated, while Venus is currently at a gibbous phase and 72% lit.

Looking west from latitude 30 north Sunday night from the US east coast... note that Mercury and Saturn are in the picture as well! (Created by the author in Stellarium). — Looking west from latitude 30 north Sunday night from the US east coast… note that Mercury and Saturn are in the picture as well! (Created by the author in Stellarium).

This will also present a good chance to see Venus during the daytime, using the nearby crescent Moon as a guide. This is a fun thing to try, and no gear is required! Though Venus may seem tough to find against the bright daytime sky, appearances are deceptive. With an albedo of 67% versus the Moon’s average of 14% Venus is actually brighter than the Moon per square arc second of size!

The Moon will also occult Spica on the evening of September 8^th for observers in the Middle East and Europe right around sunset. Spica is one of four bright stars that the Moon can occult in the current epoch, along with Antares, Aldebaran, and Regulus. This is also part of a series of fine occultations of Spica by the Moon ongoing from 2012 to 2014.

Sundown on September 8^th offers a special treat, as the 3-day old Moon passes less than a degree from Venus worldwide. The pair will fit easily into the field of view of binoculars or a telescope at low power and present an outstanding photo op.

And for observers based in Argentina and Chile, the Moon will actually occult Venus. Occultations are grand events, a split-second astronomical event in a universe that seems to usually move at a glacial pace. This particular occultation occurs for South American observers just before & after sunset.

The occultation of Venus by the Moon; the footprint over South America. (Credit: Occult 4.1.0.2).

We witnessed and recorded a similar pairing of Venus and the daytime Moon from the shores of our camp on Saint Froid Lake in northern Maine back in 2007:

Also, keep an eye out for a ghostly phenomenon known as the ashen light on the dark limb of the Moon. Also known as Earthshine, what you’re seeing is the reflection of sunlight off of the Earth illuminating the (cue Pink Floyd) dark side of the Moon. When the Moon is a crescent as seen from the Earth, the Earth is at gibbous phase as seen from the nearside of the Moon. Remember, the lunar farside and darkside are two different things! Earthshine can vary in brightness, based on the amount of cloud and snow cover present or absent on the Earth’s moonward side. My Farmer’s Almanac-consulting grandpappy would call ashen light the “Old Moon in the New Moon’s arms,” and reckon rain was a comin’…

Be sure to check out these astronomical goings on this weekend, and send those pics in to Universe Today!