Stunning Amateur Timelapse of Jupiter ‘Re-enacts’ Voyager Flyby

This animated gif shows Voyager 1's approach to Jupiter during a period of over 60 Jupiter days in 1979. Credit: NASA.

Back in the 1970’s when NASA launched the two Voyager spacecraft to Jupiter, Saturn, Uranus, and Neptune, I remember being mesmerized by a movie created from Voyager 1 images of the movement of the clouds in Jupiter’s atmosphere. Voyager 1 began taking pictures of Jupiter as it approached the planet in January 1979 and completed its Jupiter encounter in early April. During that time it took almost 19,000 pictures and many other scientific measurements to create the short movie, which you can see below, showing the intricate movement of the bright band of clouds for the first time.

Now, 35 years later a group of seven Swedish amateur astronomers achieved their goal of replicating the Voyager 1 footage, not with another flyby but with images taken with their own ground-based telescopes.

“We started this joint project back in December of 2013 to redo the NASA Voyager 1 flyby of Jupiter,” amatuer astronomer Göran Strand told Universe Today. “During 90 days we captured 560 still images of Jupiter and turned them into 90 complete maps that covered the whole of Jupiter’s surface.”

Their newly released film, above details the work they did and the hurdles they overcame (including incredibly bad weather in Sweden this winter) to make their dream a reality. They called their project “Voyager 3.”

Animated gif of the 'Voyager 3' team re-enactment of the Voyager 1 flyby. Credit: Voyager 3 team, via Kristoffer Åberg.
Animated gif of the ‘Voyager 3’ team re-enactment of the Voyager 1 flyby. Credit: Voyager 3 team, via Kristoffer Åberg.
It is really an astonishing project and those of you who do image processing will appreciate the info in the video about the tools they used and how they did their processing to create this video.

The seven Swedish astronomers who participated in the Voyager 3 project are (from left to right in the photo below) Daniel Sundström, Torbjörn Holmqvist, Peter Rosén (the project initiator), Göran Strand, Johan Warell and his daughter Noomi, Martin Högberg and Roger Utas.

The Swedish team of amateur astronomers who compiled the 'Voyager 3' project. Image courtesy Peter Rosén.
The Swedish team of amateur astronomers who compiled the ‘Voyager 3’ project. Image courtesy Peter Rosén.

Congrats to the team of Voyager 3!

You can read more about the Voyagers visits to Jupiter here from NASA.

Voyager3Movie from Peter Rosén on Vimeo.

Asteroid-Turned-Comet 2013 UQ4 Catalina Brightens: How to See it This Summer

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Though ISON may have fizzled in early 2014, we’ve certainly had a bevy of binocular comets to track this year. Thus far in 2014, we’ve had comets R1 Lovejoy, K1 PanSTARRS, and E2 Jacques reach binocular visibility. Now, and asteroid-turned-comet is set to put on a fine show this summer for northern hemisphere observers.

Veteran stargazer and Universe Today contributor Bob King told the tale last month of how the asteroid formerly known as 2013 UQ4 became comet 2013 UQ4 Catalina. Discovered last year on October 23rd 2013 during the routine Catalina Sky Survey searching for Near Earth Objects based outside of Tucson Arizona, this object was of little interest until early this year.

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A recent image of 2013 UQ4 Catalina from June 16th. The development of fine tail structure can be seen. Credit: A. Maury & J.G. Bosch.

As it rounded the Sun, astronomers recovered the asteroid and discovered that it had begun to sprout a fuzzy coma, a very un-asteroid-like thing to do. Then, on May 7th, Taras Prystavski and Artyom Novichonok — of Comet ISON fame — conducted observations of 2013 UQ4 and concluded that it was indeed an active comet.

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The orbital path of UQ4 Catalina in early July. Created using the JPL Solar System Dynamics Small Body Database Browser.

Hovering around +13th magnitude last month, newly rechristened 2013 UQ4 Catalina was a southern hemisphere object visible only from larger backyard telescopes. That should change, however, in the coming weeks if activity from this comet holds up.

Light curve
The light curve of UQ4 Catalina with current observations (dots) noted. Credit:  Seiichi Yoshida/Aerith.net.

2013 UQ4 belongs to a class of objects known as damocloids. These asteroids are named after the prototype for the class 5335 Damocles and are characterized as long-period bodies in retrograde and highly eccentric orbits. These are thought to be inactive varieties of comet nuclei, and other asteroids in the damocloid series such as C/2001 OG 108 (LONEOS) and C/2002 VQ94 (LINEAR) also turned out to be comets. Damocloids also exhibit the same orbital characteristics of that most famous inner solar system visitor of them all; Halley’s Comet.

The path of Comet 9PM 30deg north
The path of Comet UQ4 Catalina looking towards the NE at 9PM local in early July from latitude 30 degrees north. Credit: Stellarium.

The good news is, 2013 UQ4 Catalina is brightening on schedule and should be a binocular object greater than +10th magnitude by the end of June. Recent observations, including those made by Alan Hale (of comet Hale-Bopp fame) place the comet at magnitude +11.9 with a bullet. The comet is currently placed high in the east in the constellation Pisces at dawn, and will soon speed northward and vault across the sky as it crosses the ecliptic plane this week. In fact, comet 2013 UQ4 Catalina reaches perihelion on July 6th only four days before its closest approach to the Earth at 47 million kilometres distant, when it may well reach a peak magnitude of +7. At that point, the comet will have an apparent motion of about 7 degrees a day — that’s the span of a Full Moon once every 1 hour and 42 minutes — as it rises in the constellation Cepheus to the northeast at dusk in early July. A fine placement, indeed. And speaking of the Moon, our natural satellite reaches New phase later this month on June 27th, another good reason to begin searching for 2013 UQ4 Catalina now.

Here’s a list of notable events to watch out for and aid you in your quest as comet 2013 UQ4 Catalina crosses the summer sky:

June 16th: The comet crosses north of the ecliptic plane.

June 20th: The waning crescent Moon passes 3 degrees from the comet.

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The celestial path of the comet from June 16th to July 15th… Credit: Starry Night Education software.

June 29th: Crosses into the constellation of Andromeda.

July 1st: Passes less than one degree from the +2nd magnitude star Alpheratz.

July 2nd: Crosses briefly into the constellation Pegasus before passing back into Andromeda.

July 6th: The comet reaches perihelion or its closest point to the Sun at 1.081 A.U.s distant.

July 7th: Crosses into the constellation of Lacerta and passes the deep sky objects NGCs 7296, 7245, 7226.

July 8th: Crosses into the constellation Cepheus and across the galactic plane.

July 9th: Passes a degree from the Elephant Trunk open star cluster.

July 10th: Passes less than one degree from the stars Eta (magnitude +3.4) and Theta (magnitude +4.2) Cephei.

July 10th: Passes 2 degrees from the +7.8 magnitude Open Cluster NGC 6939.

July 10th: Passes closest to Earth at 0.309 A.U.s or 47 million kilometres distant.

July 11th: Crosses into the constellation Draco.

July 11th: Reaches its most northerly declination of 64 degrees.

July 12th: Photo op: the comet passes 3 degrees from the Cat’s Eye Nebula.

July 15th- August 20th
… and the path of the comet from July 15th to August 20th. Credit: Starry Night.

July 17th: The comet passes into the astronomical constellation of Boötes.

July 31st: Passes just 2 degrees from globular cluster NGC5466 (+9th magnitude) and 6 degrees from the famous globular cluster Messier 3.

From there on out, the comet drops below naked eye visibility and heads back out in its 470 year orbit around the Sun. Be sure to check out comet 2013 UQ4 Catalina this summer… what will the Earth be like next time it passes by in 2484 A.D.?

Astronomy Cast Ep. 349: Mercury 7 – How the US picked the First Astronauts

Before the Apollo Program, there was the Gemini Program, and before Gemini came the Mercury Program. 7 elite astronauts chosen from a pool of military test pilots. How did NASA choose these original 7 men?

Visit the Astronomy Cast Page to subscribe to the audio podcast!

We record Astronomy Cast as a live Google+ Hangout on Air every Monday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch here on Universe Today or from the Astronomy Cast Google+ page.

Gaia Space Telescope Team Battles ‘Stray Light’ Problems At Start Of Mission

Artist's conception of the Gaia telescope backdropped by a photograph of the Milky Way taken at the European Southern Observatory. Credit: ESA/ATG medialab; background: ESO/S. Brunier

Europe’s powerful Milky Way mapper is facing some problems as controllers ready the Gaia telescope for operations. It turns out that there is “stray light” bleeding into the telescope, which will affect how well it can see the stars around it. Also, the telescope optics are also not transmitting as efficiently as the design predicted.

Controllers emphasize the light problem would only affect the faintest visible stars, and that tests are ongoing to minimize the impact on the mission. Still, there will be some effect on how well Gaia can map the stars around it due to this issue.

“While there will likely be some loss relative to Gaia’s pre-launch performance predictions, we already know that the scientific return from the mission will still be immense, revolutionizing our understanding of the formation and evolution of our Milky Way galaxy and much else,” wrote the Gaia project team in a blog post.

Both of these problems have been known publicly since April, and the team has been working hard in recent months to pinpoint the cause. Of the two of them, it appears the team is having the most success with the optics transmission problems. They have traced the issue to water vapor in the telescope that freezes (no surprise since Gaia operates between -100 degrees Celsius and -150 Celsius, or -148 Fahrenheit and -238 Fahrenheit.)

Soyuz VS06, with Gaia space observatory, lifted off  from Europe's Spaceport, French Guiana, on 19 December 2013. (ESA–S. Corvaja)
Soyuz VS06, with Gaia space observatory, lifted off from Europe’s Spaceport, French Guiana, on 19 December 2013. (ESA–S. Corvaja)

The team turned on heaters on Gaia (on its mirrors and focal plane) to get rid of the ice before turning the temperature back down so the telescope can do its work. While some ice was anticipated (that’s why the heaters were there) there was more than expected. The spacecraft is also expected to equalize its internal pressure over time, sending out gases that again, could freeze and cause interference, so more of these “decontamination” procedures are expected.

The stray light problem is proving to be more stubborn. The light waves from sunlight and brighter sources of light in the sky are likely moving around the sunshield and bleeding into the telescope optics, which was unexpected (but the team is now trying to model and explain.)

Perhaps it was more ice. The challenge is, there were no heaters placed into the thermal tent area that could be responsible for the issue, so the team at first considered moving the position of Gaia to have sunlight strike that area and melt the ice.

GAIA Telescope Array - Credit: ESA
GAIA Telescope Array – Credit: ESA

 

Simulations showed no safety problems with the idea, but “there is currently no plan to do so,” the team wrote. That’s because some tests on ground equipment in European laboratories didn’t show any strong evidence for or against layers of ice interfering with the stray light. So there didn’t seem to be much point to doing the procedure.

So instead, the idea is to do “modified observing strategies” to collect the data and then tweaking the software on the spacecraft and on the ground to “best optimize the data we will collect,” Gaia managers wrote.

“The stray light is variable across Gaia’s focal plane and variable with time, and has a different effect on each of Gaia’s science instruments and the corresponding science goals. Thus, it is not easy to characterise its impact in a simple way,” they added. They predict, however, that a star at magnitude 20 (the limit of Gaia’s powers) would see its positional accuracy mapping reduced by about 50%, while stars that are brighter would have less impact.

A diagram of the Gaia telescope payload (largest size available). Credit: European Space Agency
A diagram of the Gaia telescope payload (largest size available). Credit: European Space Agency

“It is important to realize that for many of Gaia’s science goals, it is these relatively brighter stars and their much higher accuracy positions that are critical, and so it is good to see that they are essentially unaffected. Also, the total number of stars detected and measured will remain unchanged,” the managers added.

The team is also tracking a smaller issue with a system that is supposed to measure the angle of separation between the two telescopes of Gaia. It’s needed to measure how small changes in temperature affect the angle between the telescopes. While the system is just fine, the angle is varying more than expected, and more work will be needed to figure out what to do next.

But nevertheless, Gaia is just about ready to start a science session that will last about a month. The team expects to have a better handle on what the telescope is capable of, and how to work with these issues, after that time. Gaia operates about 1.5 million km (932,000 miles) away from Earth in a gravitationally stable point in space known as L2, so it’s a bit too far for a house call such as what we were used to with the Hubble Space Telescope.

Source: European Space Agency

‘Weird’ Dust Ring Baffles In Cloud That Will Give Birth To Giant Stars

A picture of NGC 7538 from data taken by the Herschel Space Observatory. Credit: ESA/NASA/JPL-Caltech/Whitman College

Long after telescopes cease operating, their bounty of scientific data continues to amaze. Here’s an example of that: this Herschel Space Telescope image of this dust and gas cloud about 8,000 light-years away.

The examination of NGC 7358 revealed a “weird” dusty ring in the cloud — nobody quite knows how it got there — as well as a baker’s dozen of huge dust clumps that could one day form gigantic stars.

“The 13 clumps spotted in NGC 7358, some of which lie along the edge of the mystery ring, all are more than 40 times more massive than the sun,” NASA stated.

“The clumps gravitationally collapse in on themselves, growing denser and hotter in their cores until nuclear fusion ignites and a star is born. For now, early in the star-formation process, the clumps remain quite cold, just a few tens of degrees above absolute zero. At these temperatures, the clumps emit the bulk of their radiation in the low-energy, submillimeter and infrared light that Herschel was specifically designed to detect.”

Artist's impression of the Herschel Space Telescope. Credit: ESA/AOES Medialab/NASA/ESA/STScI
Artist’s impression of the Herschel Space Telescope. Credit: ESA/AOES Medialab/NASA/ESA/STScI

More observations are planned to learn about the nature of the dusty ring. So far, astronomers can say it is 35 light-years at its longest axis, 25 light-years at its shortest-axis, and has a mass of about 500 times of the sun. The astronomers took a look at it with the James Clerk Maxwell Telescope in Hawaii to gain some more information.

“Astronomers often see ring and bubble-like structures in cosmic dust clouds,” NASA added.” The strong winds cast out by the most massive stars, called O-type stars, can generate these expanding puffs, as can their explosive deaths as supernovas. But no energetic source or remnant of a deceased O-type star, such as a neutron star, is apparent within the center of this ring. It is possible that a big star blew the bubble and, because stars are all in motion, subsequently left the scene, escaping detection.”

While the research was published in the Astrophysical Journal about a year ago, the image appears to be a new entry on NASA’s and Herschel’s websites. You can also read the paper (led by Cassandra Fallscheer, a visiting assistant professor of astronomy at Whitman College in Walla Walla, Washington) in preprint version on Arxiv.

The Herschel telescope was shut down almost exactly a year ago after the liquid helium that cooled its instruments ran out.

Source: Jet Propulsion Laboratory

An Ocean On Pluto’s Moon? Hopeful Scientists Will Keep An Eye Out For Cracks

Artist impression of Pluto and Charon (NASA)

It’s a lot of speculation right now, but the buzz in a new NASA study is Pluto’s largest moon (Charon) could have a cracked surface.

If the New Horizons mission catches these cracks when it whizzes by in 2015, this could hint at an ocean underneath the lunar surface — just like what we talk about with Europa (near Jupiter) and Enceladus (near Saturn). But don’t get too excited — it’s also possible Charon had an ocean, but it froze out over time.

“Our model predicts different fracture patterns on the surface of Charon depending on the thickness of its surface ice, the structure of the moon’s interior and how easily it deforms, and how its orbit evolved,” stated Alyssa Rhoden of NASA’s Goddard Space Flight Center in Maryland, who led the research.

“By comparing the actual New Horizons observations of Charon to the various predictions, we can see what fits best and discover if Charon could have had a subsurface ocean in its past, driven by high eccentricity.”

It seems an unlikely proposition given that Pluto is so far from the Sun — about 29 times further away than the Earth is. Its surface temperature is -380 degrees Farhenheit (-229 degrees Celsius), which — to say the least — would not be a good environment for liquid water on the surface.

But it could happen with enough tidal heating. To back up, both Europa and Enceladus are small moons fighting gravity from their much larger gas giant planets, not to mention a swarm of other moons. This “tug-of-war” not only makes their orbits eccentric, but creates tides that change the interior and the surface, causing the cracks. Perhaps this might have kept subsurface oceans alive on these moons.

Encaladus, a moon of Saturn, as shown in this Voyager 1 image. Credit: NASA
Encaladus, a moon of Saturn, as shown in this Voyager 1 image. Credit: NASA

Since Charon once had an eccentric orbit, perhaps it also had tidal heating. Scientists think that the moon was created after a large object smacked into Pluto and created a chain of debris (similar to the leading theory for how our Moon was formed). The proportionally huge Charon — it’s one-eighth Pluto’s mass — would have been close to its parent planet, causing gravity to tug on both objects and creating friction inside their interiors.

“This friction would have also caused the tides to slightly lag behind their orbital positions,” NASA stated. “The lag would act like a brake on Pluto, causing its rotation to slow while transferring that rotational energy to Charon, making it speed up and move farther away from Pluto.”

But this friction would have ceased long ago, given that observations show Charon orbits in a stable circle further away from Pluto, and there are no extraneous tugs on its path today. So another possibility is there was an ocean beneath the moon’s surface that today is a block of ice.

The study was published in April in the journal Icarus. And by the way, some have even speculated that Pluto itself could have an ocean.

Source: NASA

Hubble Hubba: Stars Are Being Born Around A Black Hole In Galaxy’s Center

Hubble Space Telescope picture of galaxy NGC 3081. Credit: ESA/Hubble & NASA; acknowledgement: R. Buta (University of Alabama)

Let’s just casually look at this image of a galaxy 86 million light-years away from us. In the center of this incredible image is a bright loop that you can see surrounding the heart of the galaxy. That is where stars are being born, say the scientists behind this new Hubble Space Telescope image.

“Compared to other spiral galaxies, it looks a little different,” NASA stated. “The galaxy’s barred spiral center is surrounded by a bright loop known as a resonance ring. This ring is full of bright clusters and bursts of new star formation, and frames the supermassive black hole thought to be lurking within NGC 3081 — which glows brightly as it hungrily gobbles up in-falling material.”

A “resonance ring” refers to an area where gravity causes gas to stick around in certain areas, and can be the result of a ring (like you see in NGC 3081) or close-by objects with a lot of gravity. Scientists added that NGC 3081, which is in the constellation Hydra or the Sea Serpent, is just one of many examples of barred galaxies with this type of resonance.

By the way, this image is a combination of several types of light: optical, infrared and ultraviolet.

Source: NASA Goddard Space Flight Center

How to See Airglow, the Green Sheen of Night

Airglow shows as wavy stripes of pale green across the northeastern sky on May 24, 2014. Andromeda Galaxy at left. the banding was faintly visible with the naked eye as a soft, diffuse glow. The red glow at lower left is airglow from atomic oxygen 90-185 miles up. Details: 20mm lens, ISO 3200, 30". Credit: Bob King

Emerald green, fainter than the zodiacal light and visible on dark nights everywhere on Earth, airglow pervades the night sky from equator to pole. Airglow turns up in our time exposure photographs of the night sky as ghostly ripples of aurora-like light about 10-15 degrees above the horizon. Its similarity to the aurora is no coincidence. Both form at around the same altitude of  60-65 miles (100 km) and involve excitation of atoms and molecules, in particular oxygen. But different mechanisms tease them to glow. 

Photo taken of Earth at night from the International Space Station showing bright splashes of city lights and the airglow layer off in the distance rimming the Earth's circumference. Credit: NASA
Earth at night from the International Space Station showing bright splashes of city lights and the airglow layer created by light-emitting oxygen atoms some 60 miles high in the atmosphere.  This green cocoon of light is familiar to anyone who’s looked at photos of Earth’s night-side from orbit. Credit: NASA

Auroras get their spark from high-speed electrons and protons in the solar wind that bombard oxygen and nitrogen atoms and molecules. As excited electrons within those atoms return to their rest states, they emit photons of green and red light that create shimmering, colorful curtains of northern lights.

Green light from excited oxygen atoms dominates the glow. The atoms are 90-100 km (56-62 mile) high in the thermosphere. The weaker red light is from oxygen atoms further up. Sodium atoms, hydroxyl radicals (OH) and molecular oxygen add to the light. Credit: Les Cowley
Green light from excited oxygen atoms dominates the light of airglow. The atoms are 56-62 miles high in the thermosphere. The weaker red light is from oxygen atoms further up. Sodium atoms, hydroxyl radicals (OH) and molecular oxygen add their own complement to the light. Credit: Les Cowley

Airglow’s subtle radiance arises from excitation of a different kind. Ultraviolet light from the daytime sun ionizes or knocks electrons off of oxygen and nitrogen atoms and molecules;  at night the electrons recombine with their host atoms, releasing energy as light of different colors including green, red, yellow and blue.  The brightest emission, the one responsible for creating the green streaks and bands visible from the ground and orbit, stems from excited oxygen atoms beaming light at 557.7 nanometers, smack in the middle of  the yellow-green parcel of spectrum where our eyes are most sensitive.

Airglow across the eastern sky below the summertime Milky Way. Notice that unlike the vertical rays and gently curving arcs of the aurora, airglow is banded and streaky and in places almost fibrous. Credit: Bob King
Airglow across the eastern sky below the summertime Milky Way. Notice that unlike the vertical rays and gently curving arcs of the aurora, airglow is banded, streaky and in places almost fibrous. It’s brightest and best visible 10-15 degrees high along a line of sight through the thicker atmosphere. If you look lower, its feeble light is absorbed by denser air and dust. Looking higher, the light spreads out over a greater area and appears dimmer. Credit: Bob King
A large, faint patch of airglow below the Dippers photographed last month on a very dark night. To the eye, all airglow appears as colorless streaks and patches. Unlike the aurora, it's typically too faint to see color. No problem for the camera though! Credit: Bob King
A large, faint patch of airglow below the Dippers photographed May 24. To the eye, airglow appears as colorless streaks and patches. Unlike the aurora, it’s typically too faint to excite our color vision. Time exposures show its colors well. This swatch is especially faint because it’s much higher above the horizon. Credit: Bob King

That’s not saying airglow is easy to see! For years I suspected streaks of what I thought were high clouds from my dark sky observing site even when maps and forecasts indicated pristine skies. Photography finally taught me to trust my eyes. I started noticing green streaks near the horizon in long-exposure astrophotos. At first I brushed it off as camera noise. Then I noticed how the ghostly stuff would slowly shape-shift over minutes and hours and from night to night. Gravity waves created by jet stream shear, wind flowing over mountain ranges and even thunderstorms in the lower atmosphere propagate up to the thermosphere to fashion airglow’s ever-changing contours.

Airglow across Virgo last month. Mars is the bright object right and below center. Credit: Bob King
An obvious airglow smear across Virgo last month. Mars is the bright object below and right of center. Light pollution from Duluth, Minn. creeps in at lower left. Credit: Bob King

Last month, on a particularly dark night, I made a dedicated sweep of the sky after my eyes had fully adapted to the darkness. A large swath of airglow spread south of the Big and Little Dipper. To the east, Pegasus and Andromeda harbored hazy spots of  varying intensity, while brilliant Mars beamed through a long smear in Virgo.

To prove what I saw was real, I made the photos you see in this article and found they exactly matched my visual sightings. Except for color. Airglow is typically too faint to fire up the cone cells in our retinas responsible for color vision. The vague streaks and patches were best seen by moving your head around to pick out the contrast between them and the darker, airglow-free sky. No matter what part of the sky I looked, airglow poked its tenuous head. Indeed, if you were to travel anywhere on Earth, airglow would be your constant companion on dark nights, unlike the aurora which keeps to the polar regions. Warning – once you start seeing it, you

Excited oxygen at higher altitude creates a layer of faint red airglow. Sodium excitation forms the yellow layer at 57 miles up. Credit: NASA with annotations by Alex Rivest
Excited oxygen at higher altitude creates a layer of faint red airglow. Sodium excitation forms the yellow layer at 57 miles up. Airglow is brightest during daylight hours but invisible against the sunlight sky. Credit: NASA with annotations by Alex Rivest

Airglow comes in different colors – let’s take a closer look at what causes them:

* Red –  I’ve never seen it, but long-exposure photos often reveal red/pink mingled with the more common green. Excited oxygen atoms much higher up at 90-185 miles (150-300 km) radiating light at a different energy state are responsible. Excited -OH (hydroxyl) radicals give off deep red light in a process called chemoluminescence when they react with oxygen and nitrogen. Another chemoluminescent reaction takes place when oxygen and nitrogen molecules are busted apart by ultraviolet light high in the atmosphere and recombine to form nitric oxide  (NO).

* Yellow – From sodium atoms around 57 miles (92 km) high. Sodium arrives from the breakup and vaporization of minerals in meteoroids as they burn up in the atmosphere as meteors.

* Blue – Weak emission from excited oxygen molecules approximately 59 miles (95 km) high.

Comet Lovejoy passing behind green oxygen and sodium airglow layers on December 22, 2011 seen from the space station. Credit: NASA/Dan Burbank
Comet Lovejoy passing behind green oxygen and sodium airglow layers on December 22, 2011 seen from the space station. Credit: NASA/Dan Burbank

Airglow varies time of day and night and season, reaching peak brightness about 10 degrees, where our line of sight passes through more air compared to the zenith where the light reaches minimum brightness. Since airglow is brightest around the time of solar maximum (about now), now is an ideal time to watch for it. Even cosmic rays striking molecules in the upper atmosphere make a contribution.


See lots of airglow and aurora from orbit in this video made using images taken from the space station.

If you removed the stars, the band of the Milky Way and the zodiacal light, airglow would still provide enough illumination to see your hand in front of your face at night. Through recombination and chemoluminescence, atoms and molecules creates an astounding array of colored light phenomena. We can’t escape the sun even on the darkest of nights.

Jill Tarter Video: From Searching For Aliens To Helping Hollywood Stars, And Back Again

SETI's Jill Tarter. Credit: SETI

Imagine you’re a researcher at a cocktail party. You meet Carl Sagan (Carl Sagan!) and he hands you a novel. And it turns out that you are the inspiration for the major character in that book.

What was SETI researcher Jill Tarter’s reaction when this actually happened and she heard about Ellie, the protagonist in Contact?

“I said, ‘Look. Here’s the deal. As long as she doesn’t eat ice cream cones for lunch, nobody’s going to think it’s me.’ That was the thing that was sort of my most peculiar habit of the time,” Tarter recalls in this new video for PBS.

If you can think of all the media attention that surrounded the reboot of Cosmos, imagine that it’s 1997 and Contact has just been made into a movie. Tarter became a celebrity overnight, and describes the impact on her life. But she also explains why searching for life beyond Earth has relevance.

Tarter’s video is just one of several featured in the show “”The Secret Life of Scientists and Engineers.” To get the full story on Tarter’s links to Contact, check out this Universe Today story from 2012 where she reflected on the 15th anniversary of the movie.

Too WISE to be Fooled by Dust: Over 300 New Star Clusters Discovered

A new study by Brazilian astronomers details the discoveries of some 300 new star clusters using the WISE space telescope (credit NASA/JPL-Caltech/UCLA).

Brazilian astronomers have discovered some 300+ star clusters that were largely overlooked owing to sizable obscuration by dust.  The astronomers, from the Universidade Federal do Rio Grande do Sul, used data obtained by NASA’s WISE (Wide-Field Infrared Survey Explorer) space telescope to detect the clusters.

“WISE is a powerful tool to probe … young clusters throughout the Galaxy”, remarked the group.  The clusters discovered were previously overlooked because the constituent stars are deeply embedded in their parent molecular cloud, and are encompassed by dust.   Stars and star clusters can emerge from such environments.

The group added that, “The present catalog of new clusters will certainly become a major source for future studies of star cluster formation.”   Indeed, WISE is well-suited to identify new stars and their host clusters because infrared radiation is less sensitive to dust obscuration.  The infrared part of the electromagnetic spectrum is sampled by WISE.

An optical (DSS) and infrared (WISE) image of the same field.  A cluster of young stars is not apparent in the optical (left) image owing to obscuration by dust.  However, a young star cluster is apparent in the right image because the dust reradiates the absorbed radiation in the infrared regime.  The new study highlights the discovery of numerous  star clusters discovered using infrared (WISE) data (image credit: DSS/NASA and assembly by D. Majaess).
An optical (DSS) and infrared (WISE) image of the same field. A cluster of young stars is not apparent in the optical (left) image owing to obscuration by dust.  However, a young star cluster is readily apparent in the right image because dust obscuration is significantly less at infrared wavelengths. A new study by a team of astronomers highlights the discovery of numerous star clusters using WISE data (image credit: DSS/NASA/IPAC and assembly by D. Majaess).

Historically, new star clusters were often identified while inspecting photographic plates imaged at (or near) visible wavelengths (i.e., the same wavelengths sampled by the eye).  Young embedded clusters were consequently under-sampled since the amount of obscuration by dust is wavelength dependent.  As indicated in the figure above, the infrared observations penetrate the dust by comparison to optical observations.

The latest generation of infrared survey telescopes (e.g., Spitzer and WISE) are thus excellent instruments for detecting clusters embedded in their parent cloud, or hidden from detection because of dust lying along the sight-line.  The team notes that, “The Galaxy appears to contain 100000 open clusters, but only some 2000 have established astrophysical parameters.”  It is hoped that continued investigations using WISE and Spitzer will help astronomers minimize that gap.

The discoveries are described in a new study by D. Camargo, E. Bica, and C. Bonatto that is entitled “New Glactic embedded cluster and candidates from a WISE survey“.   The study has been accepted for publication, and will appear in a forthcoming issue of the journal New Astronomy.  For more information on Galactic star clusters see the Dias et al. catalog, the WEBDA catalog, or the Star Clusters Young & Old Newsletter.  Thanks to K. MacLeod for the title suggestion.

The WISE (Wide-field Infrared Survey Explorer) space telescope was used to discover numerous new star clusters (image credit: NASA)(.
The WISE (Wide-field Infrared Survey Explorer) space telescope was used to discover numerous star clusters (image credit: NASA).