So many of the forces in space depend on equilibrium, that point where forces perfectly balance out. It defines the shape of stars, the orbits of planets, even the forces at the cores of galaxies. Let’s take a look at how parts of the Universe are in perfect balance.
In the end, everything dies, even plucky space robots. Today we examine the last days of a series of missions. How do spacecraft tend to die, and what did in such heroes as Kepler, Spirit, and Galileo (the missions… not the people).
And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.
Billions of aspen seeds float by the sun on tiny hairs creating a multicolored corona around the sun yesterday. To see and photograph the rings, I used a power pole to block the sun. Credit: Bob King
For the past two weeks puffy clumps of seeds have been riding the air in my town. You can’t avoid them. Open a door and they’ll breeze right in. Take a deep breath and you’d better be careful you don’t take a few down the windpipe.
Every June the many aspen trees that call northern Minnesota home release their booty of tiny seeds that parachute through the air on tiny clusters of hairs. And while they all have no particular place to go, their combined and unintentional effect is to create a series of beautiful colored rings about the Sun called a corona.
A single aspen seed (left) only about 1 mm across embedded in a cottony fluff of tiny hairs. At right is a spider web. Both show colors caused by bending and interference of light, a phenomenon called diffraction. Credit: Bob King (left) and Andrew Kirk
Reach your hand up to block the Sun and if your eyes can stand the glare of blue-white sky, you’ll see bazillions of tiny flecks a-flying. If you were to capture one and study it up close, you’d see it diffractlight in tiny glimmers of chrome green and purple.
When light from the sun or moon strikes a tiny water droplet, speck of pollen or aspen seed hairs, it’s scattered in different directions. Some of the scattered waves reinforce each other to make a bright ring of light in the sky while other waves cancel each other out to create a dimmer ring. A series of alternating rings around the sun is called a diffraction pattern or corona. Credit and copyright: Les Cowley www.atoptics.co.uk
Light is always getting messed with by tiny things. When it comes to aspen seeds, as rays of light – made of every color of the rainbow – bend around the hairy obstacles they interfere with one another like overlapping, expanding wave circles in a pond. Some of the waves reinforce each another and others cancel out. Our eyes see a series of colored fringes that flash about the tiny hairs.
Most halos are circular but pollen halos like this one around the moon often have unusual shapes like this oval with bulging sides and top. Credit: Bob King
The exact same thing happens when light has to step around minute water droplets, pollen grains and our hairy aspen fluffs when they’re drift through the air overhead. Overlapping wavelets of light “interfere” with one another to form a series of colorful concentric circles called a solar corona. While the same in name, this corona is an earthly one unrelated to the huge, hot coronal atmosphere that surrounds our star.
Oil-coated water droplets also show beautiful diffraction colors for a similar reason as clouds and pollen do . Light reflecting from the bottom surface of the oil film interferes with light reflecting off the top of the layer to create shifting patterns of color. Credit: Bob King
The ones created by seed hairs and pollen require clear skies and a safe way to block the Sun’s overwhelming light. My filter of choice is the power pole mostly because they’re handy. Sunglasses help to reduce the glare and eye-watering wincing.
While I can’t be 100% certain the chromatic bullseye was painted by poplar hair deflections – there’s always a chance pollen played a part – I’ve seen similar displays when the seeds have passed this way before.
Iridescent clouds are another form of a corona formed by minute water droplets diffracting light. Credit: Bob King
Coronas created by water droplets in mid-level clouds are much more common, and the familiar “ring around the sun” or solar halo is an entirely different creature. Here, light is bent or refracted through billions of microscopic six-sided ice crystals.
I figure that if the night is cloudy, the play of light and clouds in the daytime sky often makes for an enjoyable substitute.
The Spiderweb, imaged by the Hubble Space Telescope – a central galaxy (MRC 1138-262) surrounded by hundreds of other star-forming 'clumps'. Credit: NASA, ESA, George Miley and Roderik Overzier (Leiden Observatory)
Once upon a time, when the Universe was just about three billion years old, galaxies started to form. Now astronomers using a CSIRO radio telescope have captured evidence of the raw materials these galaxies used to fashion their first stars… cold molecular hydrogen gas, H2. Even though we can’t see it directly, we know it is there by using another gas that reveals its presence – carbon monoxide (CO) – a radio wave emitter.
The telescope is CSIRO’s Australia Telescope Compact Array telescope near Narrabri, NSW. “It one of very few telescopes in the world that can do such difficult work, because it is both extremely sensitive and can receive radio waves of the right wavelengths,” says CSIRO astronomer Professor Ron Ekers.
One of the studies of these “raw” galaxies was performed by astronomer Dr. Bjorn Emonts of CSIRO Astronomy and Space Science. He and fellow researchers employed the Compact Array to observe and record a gigantic and distant amalgamation of “star forming clumps or proto-galaxies” which are congealing together to create a single massive galaxy. This framework is known as the “Spiderweb” and is theorized to be at least ten thousand million light years distant. The Compact Array radio telescope is capable of picking up the signature of star formation, giving astronomers vital clues about how early galaxies began star formation.
In blue, the carbon monoxide gas detected in and around the Spiderweb. Credit: B. Emonts et al (CSIRO/ATCA)The “Spiderweb” was loaded. Here Dr. Emont and his colleagues found the molecular hydrogen gas fuel they were seeking. It covered an area of space almost a quarter of a million light-years across and contained at least sixty thousand million times the mass of the Sun! Surely this had to be the material responsible for the new stars seen sprinkled across the region. “Indeed, it is enough to keep stars forming for at least another 40 million years,” says Emonts.
In another research project headed by Dr. Manuel Aravena of the European Southern Observatory, the scientists measured the CO – the indicator of H2 – in two very distant galaxies. The signal of the faint radio waves was amped up by the gravitational fields of the additional galaxies – the “line of sight” members – which created gravitational lensing. Says Dr. Aravena, “This acts like a magnifying lens and allows us to see even more distant objects than the Spiderweb.”
Dr. Aravena’s team went to work measuring the amount of H2 in both of their study galaxies. One of these, SPT-S 053816-5030.8, produced enough radio emissions to allow them to infer how quickly it was forming stars – “an estimate independent of the other ways astronomers measure this rate.”
The Compact Array was tuned in. Thanks to an upgrade which increased its bandwidth – the amount of the radio spectrum which can be observed at any particular time – it is now sixteen times stronger and capable of reaching a range from 256 MHz to 4 GHz. That makes it a very sensitive ear!
“The Compact Array complements the new ALMA telescope in Chile, which looks for the higher-frequency transitions of CO,” says Ron Ekers.
An artist's conception of future Mars astronauts. Credit: NASA/JPL-Caltech
We all love space here and we’re sure, given that thousands of people applied for a one-way trip to Mars, that at least some of you want to spend a long time in a spacecraft. But have you thought about the bacteria that will be going along with you?
If you don’t feel too squirmy to read on, understand this: one type of bacteria grown aboard two shuttle missions ended up being bigger and thicker than control colonies on Earth, new NASA research shows.
Two astronaut crews aboard space shuttle Atlantis grew colonies of bacteria (more properly speaking, biofilms) on behalf of researchers on Earth. Most biofilms are harmless, but a small number could be associated with disease.
Biofilms were all over the Mir space station, and managing them is also a “challenge” (according to NASA) on the International Space Station. Well, here’s how they appeared in this study:
“The space-grown communities of bacteria, called biofilms, formed a ‘column-and-canopy’ structure not previously observed on Earth,” NASA stated. “Biofilms grown during spaceflight had a greater number of live cells, more biomass, and were thicker than control biofilms grown under normal gravity conditions.”
Astronauts strut their superpowers on the final shuttle mission, STS-135. Turns out bacteria acquire some super-growth in microgravity, too. Credit: NASA
The type of microorganism examined was Pseudomonas aeruginosa, which was grown for three days each on STS-132 and STS-135 in artificial urine. That was chosen because, a press release stated, “it is a physiologically relevant environment for the study of biofilms formed both inside and outside the human body, and due to the importance of waste and water recycling systems to long-term spaceflight.”
Each shuttle mission had several vials of this … stuff … in which to introduce the bacteria in orbit. The viles included cellulose membranes on which the bacteria could grow. Researchers also tested bacteria growth on Earth with similar vials. Then, all the samples were rounded up in the lab after the shuttle missions where the biofilms’ thickness, number of cells and volume was examined, as well as their structure.
This is still early-stage work, of course, requiring follow-up studies to find out how the low-gravity environment affects these microorganisms’ growth, according to lead researcher Cynthia Collins from the Rensselaer Polytechnic Institute. Metabolism and virulence are what the scientists are hoping to learn more about in the future.
Samples of bacteria Pseudomonas aeruginosa. Credit: NASA
“Before we start sending astronauts to Mars or embarking on other long-term spaceflight missions, we need to be as certain as possible that we have eliminated or significantly reduced the risk that biofilms pose to the human crew and their equipment,” stated Collins, an assistant professor in the department of chemical and biological engineering.
While this research has more immediate implications for astronaut health, the researchers added that better understanding the biofilms could lead to better treatment and prevention for Earth diseases.
“Examining the effects of spaceflight on biofilm formation can provide new insights into how different factors, such as gravity, fluid dynamics, and nutrient availability affect biofilm formation on Earth. Additionally, the research findings could one day help inform new, innovative approaches for curbing the spread of infections in hospitals,” a NASA press release stated.
If you’re not feeling too itchy by now, you can read the entire study in an April issue of PLOS ONE.
Nearby star Gliese 667C might have three potentially habitable planets. Credit: Planetary Habitability Laboratory, University of Puerto Rico Arecibo.
A closer look at the previously-studied nearby star Gliese 667C has revealed a treasure trove of planets – at least six – with three super-Earths in the habitable zone around the star. Gliese 667C is part of a triple star system (Gliese 667) and is just over one third of the mass of our Sun. Now that we know there are multiple planets in the so-called Goldilocks zone – a region where liquid water could exist — Gliese 667C might be the best candidate for harboring habitable exo-worlds.
“We knew that the star had three planets from previous studies, so we wanted to see whether there were any more,” said Mikko Tuomi from the University of Hertfordshire in the UK, one of the astronomers who led the new study of Gliese 667C. “By adding some new observations and revisiting existing data we were able to confirm these three and confidently reveal several more. Finding three low-mass planets in the star’s habitable zone is very exciting!”
Artist’s conception of the seven planets possibly found orbiting Gliese 667C. Three of them (c, f and e) orbit within the habitable zone of the star. Image is courtesy of Rene Heller/ Carnegie Institution for Science.
Tuomi, along with Guillem Anglada-Escudé of the University of Göttingen, Germany looked at existing radial velocity data from the HARPS spectrograph at ESO’s 3.6-metre telescope in Chile. The team said they are extremely confident on the data on the first five planets, while the sixth is tentative, and a potential seventh planet even more tentative.
The team writes in their paper:
Up to seven periodic signals are detected in the Doppler measurements of GJ 667C data, being the last (seventh) signal very close to our detection threshold.
The significance of the signals is not affected by correlations with activity indices and we could not identify any strong wavelength dependence with any of them.
The first six signals are strongly present in subsamples of the data. Only the seventh signal is unconfirmed using half of the data only. Our analysis indicates that any of the six stronger signals would had been robustly spotted with half the available data if each had been orbiting alone around the host star.
If all seven planets are confirmed, the system would consist of three habitable-zone super-Earths, two hot planets further in, and two cooler planets further out.
This diagram shows the system of planets around the star Gliese 667C. A record-breaking three planets in this system are super-Earths lying in the zone around the star where liquid water could exist, making them possible candidates for the presence of life. This is the first system found with a fully packed habitable zone. The relative approximate sizes of the planets and the parent star are shown to scale, but not their relative separations. Credit: ESO
But the team said the three in the habitable zone are confirmed to be super-Earths. These are planets more massive than Earth, but less massive than planets like Uranus or Neptune. This is the first time that three such planets have been spotted orbiting in this zone in the same system.
“The number of potentially habitable planets in our galaxy is much greater if we can expect to find several of them around each low-mass star,” said co-author Rory Barnes from the University of Washington, “instead of looking at ten stars to look for a single potentially habitable planet, we now know we can look at just one star and find several of them.”
Gliese 667 (a.k.a GJ 667) is 22 light-years away from Earth in the constellation of Scorpius.
The planets in the habitable zone and those closer to the star are expected to always have the same side facing the star, so that their day and year will be the same lengths, with one side in perpetual sunshine and the other always night.
The researchers say that the ‘f’ planet is “a prime candidate for habitability.”
“It likely absorbs less energy than the Earth, and hence habitability requires more greenhouse gases, like CO2 or CH4,” the team wrote in their paper. “Therefore a habitable version of this planet has to have a thicker atmosphere than the Earth, and we can assume a relatively uniform surface temperature.”
The other stars in the triple system would provide a unique sunset: the two other suns would look like a pair of very bright stars visible in the daytime and at night they would provide as much illumination as the full Moon.
Are there more planets to be found in this abundant system? Perhaps, but not in the habitable zone. The team said the new planets completely fill up the habitable zone of Gliese 667C, as there are no more stable orbits in which a planet could exist at the right distance to it.
An artist’s impression of the orbits of the planets in the Gliese 667C system:
A view of Aleksandr Misurkin during the spacewalk to prepare the International Space Station for a new Russian lab. Image via astronaut Karen Nyberg/NASA.
On Monday, two Russian cosmonauts conducted a 6-hour, 34-minute spacewalk to prepare for a new Russian module that will be launched later this year. Expedition 36 Flight Engineers Fyodor Yurchikhin and Alexander Misurkin also work on the first module ever launched for the ISS – the Zarya module which has been in space since 1998 – replacing an aging control panels located on the exterior.
The new lab will be a combination research facility, airlock and docking port, and is planned to launch late this year on a Proton rocket.
Watch video highlights of the EVA below:
This was the second of up to six Russian spacewalks planned for this year to prepare for the lab. Two U.S. spacewalks by NASA’s Chris Cassidy and Luca Parmitano of the European Space Agency are scheduled in July.
While Yurchikhin and Misurkin worked outside the ISS, the crew inside the ISS were separated and isolated from each other. Cassidy and station commander Pavel Vinogradov were sequestered in their Soyuz TMA-08M spacecraft that is attached to the Poisk module on the Russian segment due to the closure of hatches to the other passageways on the Russian side of the station which would have made the Soyuz inaccessible if there was an emergency. Parmitano and US astronaut Karen Nyberg were inside the U.S. segment of the station, and were free to move around since entry to their Soyuz vehicle (TMA-09M) was not blocked by hatch closures, since it is docked to the Rassvet module that is attached to the Zarya module.
NASA said the spacewalk was the 169th in support of space station assembly and maintenance, the sixth for Yurchikhin and the first for Misurkin.
Even the ancient astronomers knew there was something different about the planets. Unlike the rest of the stars, the planets move across the sky, backwards and forwards, round and round. It wasn’t until Copernicus that we finally had a modern notion of what exactly is going on.
Pluto & Charon as you'll never see them... imaged by Hubble in 1994. (Credit: NASA/ESA/ESO).
So you’ve seen all of the classic naked eye planets. Maybe you’ve even seen fleet-footed Mercury as it reached greatest elongation earlier this month. And perhaps you’ve hunted down dim Uranus and Neptune with a telescope as they wandered about the stars…
But have you ever seen Pluto?
Regardless of whether or not you think it’s a planet, now is a good time to try. With this past weekend’s perigee Full Moon sliding out of the evening picture, we’re reaching that “dark of the Moon” two week plus stretch where it’s once again possible to go after faint targets.
This year, Pluto reaches opposition on July 1st, 2013 in the constellation Sagittarius. This means that as the Sun sets, Pluto will be rising opposite to it in sky, and transit the meridian around local midnight.
But finding it won’t be easy. Pluto currently shines at magnitude +14, 1,600 times fainter than what can be seen by the naked eye under favorable sky conditions. Compounding the situation is Pluto’s relatively low declination for northern hemisphere observers. You’ll need a telescope, good seeing, dark skies and patience to nab this challenging object.
Pluto in Sagittarius; a wide field field of view with 10 degree finder circle. The orbital path of Pluto and the ecliptic is also noted. The red inset box is the field of view below. All graphics created by the author using Starry Night.
Don’t expect Pluto to look like much. Like asteroids and quasars, part of the thrill of spotting such a dim speck lies in knowing what you’re seeing. Currently located just over 31 Astronomical Units (AUs) distant, tiny Pluto takes over 246 years to orbit the Sun. In fact, it has yet to do so once since its discovery by Clyde Tombaugh from the Lowell observatory in 1930. Pluto was located in the constellation Gemini near the Eskimo nebula (NGC 2392) during its discovery.
And not all oppositions are created equal. Pluto has a relatively eccentric orbit, with a perihelion of 29.7 AUs and an aphelion of 48.9 AUs. It reached perihelion on September 5th, 1989 and is now beginning its long march back out of the solar system, reaching aphelion on February 19th, 2114.
A medium field finder for Pluto with a five degree field of view. The current direction of New Horizons is noted. The yellow inset box is the field of view below.
Pluto last reached aphelion on June 4th, 1866, and won’t approach perihelion again until the far off date of September 15th, 2237.
This means that Pluto is getting fainter as seen from Earth on each successive opposition. Pluto reaches magnitude +13.7 when opposition occurs near perihelion, and fades to +15.9 (over 6 times fainter) when near aphelion. It’s strange to think that had Pluto been near aphelion during the past century rather than the other way around, it may well have eluded detection!
This all means that a telescope will be necessary in your quest, and the more powerful the better. Pluto was just in range of a 6-inch aperture instrument about 2 decades ago. In 2013, we’d recommend at least an 8-inch scope and preferably larger to catch it. Pluto was an easy grab for us tracking it with the Flandrau Science Center’s 16-inch reflector back in 2006.
A one degree field of view, showing the path of Pluto from June 23rd of this year until December 2nd. Stars are labeled down to 7th magnitude, unlabeled stars are depicted down to 10th magnitude.
Pluto is also currently crossing a very challenging star field. With an inclination of 17.2° relative to the ecliptic, Pluto crosses the ecliptic in 2018 for the first time since its discovery in 1930. Pluto won’t cross north of the ecliptic again until 2179.
Pluto also crossed the celestial equator into southern declinations in 1989 and won’t head north again til 2107.
But the primary difficulty in spotting +14th magnitude Pluto lies in its current location towards the center of our galaxy. Pluto just crossed the galactic plane in early 2010 into a very star-rich region. Pluto has passed through some interesting star fields, including transiting the M25 star cluster in 2012 and across the dark nebula Barnard 92 in 2010.
A one degree narrow field of view, showing the path of Pluto from June 24th to August 6th. Stars are depicted down to 14th magnitude.
This year finds Pluto approaching the +6.7 magnitude star SAO 187108 (HIP91527). Next year, it will pass close to an even brighter star in the general region, +5.2 magnitude 29 Sagittarii. Mid-July also sees it passing very near the +10.9 magnitude globular cluster Palomar 8 (see above). This is another fine guidepost to aid in your quest.
So, how do you pluck a 14th magnitude object from a rich star field? Very carefully… and by noting the positions of stars at high power on successive nights. A telescope equipped with digital setting circles, a sturdy mount and pin-point tracking will help immeasurably. Pluto is currently located at:
Right Ascension: 18 Hours 44′ 30.1″
Declination: -19° 47′ 31″
Heavens-Above maintains a great updated table of planetary positions. It’s interesting to note that while Pluto’s planet-hood is hotly debated, few almanacs have removed it from their monthly planetary summary roundups!
You can draw the field, or photograph it on successive evenings and watch for Pluto’s motion against the background stars. It’s even possible to make an animation of its movement!
Pluto will once again reach conjunction on the far side of the Sun on January 1st 2014. Interestingly, 2013 is a rare year missing a “Plutonian-solar conjunction.” This happens roughly every quarter millennium, and last occurred in 1767. This is because conjunctions and oppositions of Pluto creep along our Gregorian calendar by about a one-to-two days per year.
An Earthly ambassador also lies in the general direction of Pluto. New Horizons, launched in 2006 is just one degree to the lower left of 29 Sagittarii. Though you won’t see it through even the most powerful of telescopes, it’s fun to note its position as it closes in on Pluto for its July 2015 flyby.
Let us know your tales of triumph and tragedy as you go after this challenging object. Can you image it? See it through the scope? How small an instrument can you still catch it in? Seeing Pluto with your own eyes definitely puts you in a select club of visual observers…
Still not enough of a challenge? Did you know that amateurs have actually managed to nab Pluto’s faint +16.8th magnitude moon Charon? Discovered in 35 years ago this month in 1978, this surely ranks as an ultimate challenge. In fact, discoverer James Christy proposed the name Charon for the moon on June 24th, 1978, as a tribute to his wife Charlene, whose nickname is “Char.” Since it’s discovery, the ranks of Plutonian moons have swollen to 5, including Nix, Hydra and two as of yet unnamed moons.
Be sure to join the hunt for Pluto this coming month. Its an uncharted corner of the solar system that we’re going to get a peek at in just over two years!
