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At this time of year, after dark we in the northern hemisphere are able to see the mighty constellation of Orion rise high in the sky with a very bright companion in a nearby constellation: Sirius – The Dog Star.
Sirius is the brightest star in the sky and can easily be found in the faint constellation of Canis Major to the left and below Orion. Its name comes from ancient Greek meaning “glowing” or “scorcher.”
Sirius (α CMa) is the alpha star in this trusty hound and is roughly 8.5 light years away from Earth, making it one of the closest stars to us. It has a tiny companion star making it a binary system composed of “Sirius A” the main component (which is a white main sequence star) and “Sirius B,” a white dwarf star. As seen with the naked eye, Sirius can be seen to twinkle many different colours low in the winter evening sky. Sirius. Image credit: Hubble
So why does Sirius twinkle?
It’s not just Sirius that twinkles; all stars twinkle. Light travels many light years from stars and right at the end of its journey, it hits Earth’s atmosphere, which consists of nitrogen, oxygen and other gasses.
Earth’s atmosphere is constantly swirling around, and wind and air currents etc distort light travelling through it. This causes the light to slightly bend or shimmer and the light from distant stars twinkle. An extreme, more down-to-Earth example of this would be heat rising off of a road or a desert causing objects behind it to distort, shimmer and change colour.
Sirius appears to twinkle or shimmer more than other stars for some very simple reasons. It is very bright, which can amplify atmospheric effects and it is also very low down in the atmosphere for those in the northern hemisphere. We are actually looking at it through a very dense part of the atmosphere which can be turbulent and contain many different particles and dust. The lower towards the horizon an observer is looking, the thicker the atmosphere. The higher an observer is looking, the thinner the atmosphere. This is also the cause of colourful sunrise and sunsets.
(Addition due to the questions in the comment section: planets don’t usually twinkle because they are closer and therefore bigger — they are disks of light instead of faraway points of light. The larger disks of light usually aren’t distorted; however if you are looking through especially turbulent areas of our atmosphere, and even sometimes when looking at planets that are low in the thicker parts of the atmosphere, they will twinkle. Phil Plait, the Bad Astronomer explains it very well on his website.)
This optical illusion is a big pain for astronomers and some very large telescopes such as those in Chile and Hawaii use special equipment and techniques to reduce the effects of the atmosphere.
One of most famous telescope of them all, the Hubble Space Telescope doesn’t get affected at all by our atmosphere as it is in space, making the light from stars crystal clear.
Twinkle, twinkle little star, now we know what you are (and why you are twinkling!)
NASA’s Kepler mission has detected no shortage of planets; more than a thousand candidates were discovered in 2011, a handful of which were Earth-like in size. As data from the mission keeps pouring in, astronomers are continuing to confirm and classify these possible exoplanets. Today, a team of astronomers from the California Institute of Technology added three more to the growing list. They have confirmed the three smallest exoplanets yet discovered.
Kepler searches for planets by looking at stars. The light from the star flickers or dips when a planet passes in front of it. At least three passes are required to confirm that the signal is from a planet, and further ground-based observations are necessary before a discovery can be confirmed.
An artist's impression of Kepler's field of view, the area in which it is constantly searching for new planets. Image Credit: Jon Lomberg/NASA
The Cal Tech team’s discovery was made with old data from Kepler. They found that the three planets are rocky like Earth and orbit a single star called KOI-961. They are also smaller than our planet; their radii are 0.78, 0.73 and 0.57 times that of Earth. As a comparison, the smallest of the three is roughly the size of Mars.
That these planets are so small is big news; they were thought to be much bigger when they were first found. Finding a planet as small as Mars is particularly amazing, said Doug Hudgins, Kepler program scientist at NASA Headquarters in Washington. It “hints that there may be a bounty of rocky planets all around us.”
The whole system is also small. The planets orbit so close to their star that their year lasts only two days. “This is the tiniest solar system found so far,” said John Johnson, the principal investigator of the research from NASA’s Exoplanet Science Institute at Cal Tech in Pasadena.
A view of Kepler's search area as seen from Earth. Image credit: Carter Roberts / Eastbay Astronomical Society
Their star, KOI-961, is a red dwarf with a diameter one-sixth that of our Sun and it is only 70 percent larger than Jupiter. This makes the system’s scale much closer to that of Jupiter and its moons than that of the Sun and the planets in our Solar System. As Johnson explains, this speaks to “the diversity of planetary systems in our galaxy.”
The type of star is also significant. Red dwarfs are the most common stars in the Milky Way galaxy, and the discovery of three rocky planets around one suggests that the galaxy could be teeming with similar rocky planets.
The team’s find, however, isn’t going to provide us with intergalactic vacation homes anytime soon. The planets are all too close to their star to be in the habitable zone, an orbit where water can exist as a liquid on the surface. Nevertheless, the tiny planets are a significant find. “These types of systems could be ubiquitous in the universe,” said Phil Muirhead, lead author of the new study from Caltech. “This is a really exciting time for planet hunters.”
Jane Houston Jones from the Jet Propulsion Laboratory provides an overview of what is in the night sky this month, including a pretty parade of planets: Venus shining brightly at dusk, while Jupiter watches from overhead; Mars comes up before midnight, and you can see Saturn near sunrise.
January Sky Northern Hemisphere Credit: Adrian West
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January brings us striking views of the night skies! You’ll be able to see well known constellations during the long hours of darkness in the Northern hemisphere, with crisp cold skies. This is an ideal time to get out and look at the wonders of the night sky as there is so much to see for the beginner and seasoned astronomer alike.
You will only need your eyes to see most of the things in this simple guide, but some objects are best seen through binoculars or a small telescope.
So what sights are there in the January night sky and when and where can we see them?
Meteor Showers Quadrantid Meteor Credit: nasa.gov
As soon as the month starts we receive a welcome treat in the form of the Quadrantid meteor shower on the evening of the 3rd/ morning of the 4th of January.
The Quadrantids can be quite an impressive shower with rates (ZHR) of up to 120 meteors per hour at the showers peak (under perfect conditions) and can sometimes produce rates of up to 200 meteors per hour. The peak is quite narrow lasting only a few hours, with activity either side of the peak being quite weak.
Due to a waxing gibbous moon, the best time to look is after midnight and through the early hours when the moon sets in time for us to see the peak which is 07:20 UT.
The radiant of the Quadrantids (where the meteors radiate from) is in the constellation of Boötes, however many people are mislead in thinking they need to look at the radiant to see the meteors – this is not true. Meteors will come from the radiant, but will appear anywhere in the whole sky at random. You can trace the shooting stars path back to the radiant to confirm if it is a meteor from the meteor shower.
For more information on how to observe and enjoy the Quadrantid meteor shower, visit meteorwatch.org
Planets
Mercury is low down in the southeast before sunrise in the first week of January.
Venus will be shining brightly in the southwest until May and will pass within 1° of Neptune the furthest planet on the 12th and 13th of January. You can see this through binoculars or a small telescope. On the 26th Venus and the Moon can be seen together after sunset. Venus
On the 5th of January, Earth will be at “Perihelion” its closest point to the Sun.
Mars brightens slightly to -0.5 during January and can be found in the tail of Leo; it can be easily spotted with the naked eye. The red Planet is close to the Moon on the night of the 13th/ 14th January. Mars
On January 2nd Jupiter and the Moon will be very close to each other with a separation of only 5° with Jupiter just below the Moon. Jupiter will continue to be one of the brightest objects in the sky this month. Jupiter
Saturn now lies in the constellation of Virgo and follows after just after Mars in Leo. Saturn
Uranus is just barely visible to the naked eye in the constellation of Pisces and can be easily spotted in binoculars or small telescopes throughout the month. The Moon will pass very close to Uranus on the 27th and will be just 5.5° to the left of the planet. Uranus Moon phases
First Quarter – 1st and 31st January
Full Moon – 9th January
Last Quarter – 16th January
New Moon – 23rd January
Constellations
Credit: Adrian West
In January the most dominant and one of the best known constellations proudly sits in the south of the sky – Orion the hunter.
Easily distinguishable as a torso of a man with a belt of three stars, a sword, club and shield, Orion acts as the centre piece of the surrounding winter constellations. Orion is viewed upside down in the Northern sky as seen from the Southern hemisphere.
Orion contains some exciting objects and its most famous are the Great Nebula in Orion(M42), which makes up the sword and is easily seen in binoculars or a telescope and bright Betelgeuse, Orion’s bright alpha star (α Orionis). Betelgeuse is a red supergiant many times larger than our Sun; it would engulf everything in our solar system out to the orbit of Jupiter, if the two stars swapped places. Betelgeuse will eventually end its life in a Supernova explosion and some people believe that it may have already exploded and the light hasn’t reached us yet. It would make for a fantastic sight! The Great Orion Nebula. Image Credit: Patrick Cullis
If you draw an imaginary line through the three belt stars of Orion and keep going up and to the right, you will come to a bright orange coloured star – Aldebaran (α Tauri) in the constellation of Taurus. Pleiades Cluster/ Seven Sisters
Taurus depicts a head of a bull with Aldebaran as its eye with a V shape that creates long horns starting from what we call the Hyades cluster, a V shaped open cluster of stars. If you continue to draw a line through the belt stars of Orion, through Aldebaran and keep going, you will eventually get to one of the gems in Taurus – The Pleiades cluster or Seven Sisters (M45) a stunning cluster of blue and extremely luminous stars and from our vantage point on Earth, the most recognisable cluster with the naked eye. A great object to scan with binoculars. A great object to hunt for with a small telescope is the Crab Nebula (M1) near the end of the lower horn of Taurus. The Crab Nebula
If you go back to our imaginary line drawn through the belt stars of Orion and draw it in the other direction, to left and below, you will come to the very bright star Sirius (α CMa) – The Dog Star in Canis Major. Sirius is the brightest star in the sky and is only 8.6 light years away, it is the closest star visible to the naked eye after the Sun.
Sirius along with Betelgeuse and Procyon (α CMi) in Canis Minor, form an asterism known as the Winter Triangle.
Directly above Orion and the Winter Triangle are the constellations of Gemini (The Twins), with the two bright stars of Castor and Pollux marking their heads and Auriga the charioteer, with its bright alpha star Capella (α Aur). Auriga is host to M36, M37 and M38 which are globular clusters and easily seen through binoculars or small telescope and Gemini plays host to M35. M37
Only a few of the objects available to see have been mentioned, so get yourself a good map, Planisphere or star atlas and see what other objects you can track down!
As 2011 is drawing to a close, the festive season is here and many of us are winding down and looking forward to the holidays. But this is a great time to look ahead to 2012 and pencil into our calendar and diaries the top astronomical events we don’t want to miss next year.
2012 is going to be a great year for astronomy observing, with some rare and exciting things taking place and a good outlook with some of the regular annual events.
So what top wonders should we expect to see and what will 2012 bring?
Conjunction of Venus and Jupiter Venus & Jupiter Conjunction Credit: Anthony Arrigo UtahSkies.org
On March 15th the Planets Venus and Jupiter will be within 3 degrees and very close to each other in the early evening sky. This will be quite a spectacle as both planets are very bright (Venus being the brightest) and the pair will burn brightly together like a pair of alien eyes watching us after the Sun sets.
This conjunction (where planets group close together as seen from Earth) will be a fantastic visual and photographic opportunity, as it’s not often you get the brightest Planets in our Solar System so close together.
Transit of Venus Transit of Venus Credit: Australian Space Alliance
For many, the transit of Venus is the year’s most anticipated astronomical event and it takes place on June 5th – 6th. The Planet Venus will pass between the Earth and the Sun and you will see Venus (a small black circle) slowly move across, or “transit” the disc of the Sun.
Transits of Venus are very rare and only a few have been witnessed since the dawn of the telescope. Be sure not to miss this very rare event as the next one isn’t visible for over another 100 years from now in 2117 and the next after that is in 2125.
The full transit of Venus in 2012 will be visible in North America, the northwest part of South America, Western Pacific, North East Asia, Japan, Australia and New Zealand. Other parts of the world will see a partial transit such as observers in the UK, who will only be able to see the last part of the transit as the Sun rises.
First contact will be at 22:09 UT and final contact will be at 04:49 UT
Take note! You have to use the right equipment for viewing the Sun, such as eclipse glasses, solar filters, or projection through a telescope. Never ever look directly at the Sun and never look at it through a normal telescope or binoculars – You will be permanently blinded! The transit of Venus will be a very popular event, so contact your local astronomy group and see if they are holding an event to celebrate this rare occasion.
Meteor Showers Don't Miss the Major 2012 Meteor Showers Credit: Shooting Star Wallpapers
2011 was a poor year for meteor showers due to the presence of a largely illuminated Moon on all of the major showers; this prevented all but the brightest meteors being seen.
In contrast 2012 brings a welcome respite from the glare of the Moon as it gives little or no interference with this year’s major showers. The only other issue left to contend with is the weather, but if you have clear skies on the evenings of these celestial fireworks, you are in for a treat.
The Quadrantid Meteor Shower peak is narrow and just before dawn on January 4th this shower is expected to have a peak rate (ZHR) of around 80 meteors per hour.
The Perseid Meteor Shower peak is fairly broad with activity increasing on the evenings of the August 9th and 10th with the showers peak on the morning of the 12th. Perseids are the most popular meteor shower of the year as it tends to be warm and the shower has very bright meteors and fireballs, with rates of 100+ an hour at its peak.
The Geminid Meteor Shower is probably the best meteor shower of the year with high rates of slow bright meteors. The peak is very broad and rates of 100+ meteors per hour can be seen. The best time to look out for Geminids is on the evenings of the 12th to 14th December, but they can be seen much earlier or later than the peak.
If you want to find out more and enjoy the meteor showers of 2012, why not join in with a meteorwatch and visit meteorwatch.org
Jupiter and the Moon Occultation of Jupiter by the Moon on July 15th as seen from Southern England Credit: Adrian West
European observers are in for a very rare treat as the Moon briefly hides the planet Jupiter on the morning of July 15th. This “lunar occultation” can be seen from southern England and parts of Europe at approximately 1:50am UT (dependant on location) and the planet re-emerges from the dark lunar limb at approximately 3:10am UT.
This is a great chance to watch this rare and bright event, and it will also be a fantastic imaging opportunity.
Annular Eclipse Annular Eclipse Credit: Kitt Peak Observatory
American observers will have treat on May 20th with an annular eclipse of the Sun. The eclipse will be visible from many western US states and a partial eclipse visible from most of North America.
Because the Moon’s orbit is not a perfect circle and is slightly elliptical, it moves closer and further away from us slightly in its orbit by 13% and on July 15th it is at its furthest point away from the Earth as it passes in front of the Sun.
Normally the Moon covers the entire disc of the Sun and creates a total solar eclipse, but because the Moon is at its furthest point in its orbit on the 15th, we get an annular eclipse, where we can still see a ring of bright light around the Sun, but we don’t get totality.
The eclipse starts roughly at 6:20pm local time for the Western US states and lasts for four and a half minutes.
As mentioned earlier; never, ever look at the Sun without proper protection such as eclipse glasses or filters for equipment! This can damage your eyes and permanently blind you. This is the same for cameras; the sensitive chips inside can be damaged.
The World Not Ending
End Of The World
Finally we get to December 21st, in which astronomy-minded folks will celebrate the solstice. But in case you haven’t heard, some have prophesied the end of the world, saying the Mayan calendar ends. This has been the subject of much discussion, comedy and media coverage, and it has even been made into films.
Will the Antichrist press the red button and will there be the Rapture? Will the Earth reverse its magnetic poles, or will we get wiped out by a solar flare, rogue comet or asteroid?
Nope, probably not. You can read our entire series which explains why this whole 2012 end-of-the-world craze is complete hokum.
All I know is 2012 is going to be a great year for astronomy with some very interesting, rare events taking place, with many more regular events to see, as well.
Artist concept of the Membrane Optical Imager for Real-Time Exploitation (MOIRE). Credit: DARPA
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“It sees you when you’re sleeping and knows when you’re awake” could be the theme song for a new spy satellite being developed by DARPA. The Defense Advanced Research Projects Agency’s latest proof-of-concept project is called the Membrane Optical Imager for Real-Time Exploitation (MOIRE), and would provide real-time images and video of any place on Earth at any time — a capability that, so far, only exists in the realm of movies and science fiction. The details of this huge eye-in-the-sky look like something right out of science fiction, as well, and it would be interesting to determine if it could have applications for astronomy as well.
MOIRE would be a geosynchronous orbital system that uses a huge but lightweight membrane optic. A 20-meter-wide membrane “eye” would be etched with a diffractive pattern, according to DARPA, which would focus light on a sensor. Reportedly it will cost $500 million USD for each space-based telescope, and it would be able to image an area greater than 100 x 100 km with a video update rate of at least one frame a second.
DARPA says the program aims to demonstrate the ability to manufacture large membranes and large structures to hold the optics flat, and also demonstrate the secondary optical elements needed to turn a diffraction-based optic into a wide bandwidth imaging device.
The MOIRE program began in March 2010 is now in the first phase of development, where DARPA is testing the concept’s viability. Phase 2 would entail system design, with Ball Aerospace doing the design and building to test a 16-foot (5 m) telescope, and an option for a Phase 3 which would include a demonstration of the system, launching a 32-foot (10 m) telescope for flight tests in orbit.
The 20 meter (66 ft) design is quite a bit larger than NASA’s next-generation James Webb Space Telescope that has an aperture of 21 feet (6.5 m).
Public Intelligence reports that such a telescope should be able to spot missile launcher vehicles moving at speeds of up to 60 mph on the ground, according to a DARPA contract. That would also require the image resolution to see objects less than 10 feet (3 m) long within a single image pixel.
Can we order one for looking for extrasolar planets?
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Have you ever seen a large ghostly disc around the Moon on a cool, calm, hazy night? If so, you have likely seen what is called an “Ice Halo” or “22° Halo.” Not only can the Moon display these ghostly rings of light, but the Sun does so in the day time too.
22° halos are visible all over the world and throughout the year; look for them whenever the sky is wispy or hazy with thin cirrus clouds – even in the hottest countries.
So what are they and why do they appear?
Ice halos or 22° radius Halos are in fact an optical illusion caused by 3 to 5 mile high, cold and very tenuous cirrostratus cloud, containing millions of tiny ice crystals.
The tiny ice crystals in the atmosphere create halos by refracting and reflecting light from the Moon. The halo is always the same diameter regardless of its position in the sky, though sometimes only parts of the circle are visible.
The much smaller coloured rings directly around the Moon or Sun are a corona produced by water droplets rather than ice crystals. They often form a rainbow effect or Moonbow.
Some people even believe they herald the onset of wet weather, but this has yet to be proved. Moon Halo Imaged December '03 in Ontario, Canada by Lauri Kangas
2011 Geminids in the Winter Triangle. Image Courtesy of John Chumack
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Have you been watching the Geminid Meteor Shower? With just hours to go before the peak, activity has been high – despite this year’s Moon! If you’d like to know more on the history of this meteor shower, then check out this great article by Adrian West. If you plan on watching and would like to do something cool and unusual, then step inside…
As you can see from this below video sent to us by John Chumack, even the bright moonlight isn’t interfering too badly with this year’s awesome Geminid meteor shower display. While it will make the fainter ones more difficult to observe, the “fireball” attitude of this meteor shower just won’t quit!
As a reminder, be sure to be out tonight and through tomorrow morning for the peak of the show. You’ll want to try when the skies are the darkest, begin before moonrise – but don’t forget the display is usually the greatest around 2:00 a.m. local time when the sky window is pointed in the optimum direction. Just look along the ecliptic plane and follow the constellation of Gemini as it cruises roughly east to west across the sky as the night goes on! If you get clouded out? Try again the next night… and the next. The stream for the Geminids is very broad and lasts for some time.
Now… if you really want to have some fun and have an iPhone, here’s a real treat…
Thanks to NASA, there’s a new application which will help you to track, count and record information about this meteor shower and any meteor shower in the world – including sporadic ones! The “Meteor Counter” app will allow you to record your observations with an easy-to-use “piano key” interface. As you strike the keys, the app records information for each meteor, including the brightness and time. Once your observing session ends, your information and data is automatically uploaded to NASA researchers for analysis.
Created by Dr. Bill Cooke, head of NASA’s Meteoroid Environment Office at NASA’s Marshall Space Flight Center and the one-and-only Dr. Tony Phillips of SpaceWeather.com, this new iPhone application is going to change the way you observe and help science, too. “We developed the iPhone app to be fun, and informative, but also to encourage going outside to observe the sky,” said Cooke. “Our hope is the app will be useful for amateur and professional astronomers — we want to include their observations in NASA’s discoveries — and have them share in the excitement of building a knowledge base about meteor showers.”
The app is more than just a set of keys, though… It has an optional recorded audio track and users can even add their own comments as they observe. This will all be sent to NASA along with the numbers – vital information which will help researchers identify meteors associated with specific radiants and one-time events. The “Meteor Counter” was designed with everyone in mind – from the beginner to the expert – and even those who have never seen a meteor before. “The beauty is that it gradually transforms novices into experts,“ says Cooke. “As an observer gains experience , we weigh their data accordingly in our analyses.”
The Meteor Counter app is also much more. It provides a newsfeed and event calendar that’s kept up-to-the-moment by professional NASA and meteor scientists, and it will help keep you informed of upcoming meteor showers and the most current sightings. The app is currently available for iPhone, iPad and iPod Touch. Download the free app at : http://itunes.apple.com/us/app/meteor-counter/id466896415. A version for other mobile devices will be available in the near future. Complete instructions for using the Meteor Counter app is available at: http://meteorcounter.com/ and more information about NASA’s Meteoroid Environment Office can be found at: http://www.nasa.gov/offices/meo/home/index.html.
A composite image of the Whirlpool Galaxy (also known as M51). The green image is from the Hubble Space Telescope and shows the optical wavelength. The submillimetre light detected by SCUBA-2 is shown in red (850 microns) and blue (450 microns). The Whirlpool Galaxy lies at an estimated distance of 31 million light years from Earth in the constellation Canes Venatici Credit: JAC / UBC / Nasa
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The stars and faint galaxies you see when you look up at the night sky are all emitting light within the visible light spectrum — the portion of the electromagnetic spectrum we can see with our unaided eyes or through optical telescopes. But our galaxy, and many others, contain huge amounts of cold dust that absorbs visible light. This accounts for the dark regions.
A new camera recently unveiled at the James Clerk Maxwell Telescope (JCMT) in Hawaii promises to figuratively shed light on this dark part of the universe. The SCUBA-2 submillimetre camera (SCUBA in this case is an acronym for Submillimetre Common-User Bolometer Array) can detect light at lower energy levels, allowing astronomers to gather data on these dark areas and ultimately learn more about our universe and its formation.
Light is measurable; its intensity or brightness is measured by photons while colour is measured by the energy of the photons. Red photons have the least energy and violet photons have the most energy. This can also be thought of in terms of wavelengths. Light at longer wavelengths have less energy and light at shorter wavelengths have more energy. This continues beyond the visible light spectrum. As electromagnetic waves get shorter, we get ultraviolet light, x-rays, and gamma rays. As wavelengths get longer, we get infrared light, submillimetre light, and finally radio waves.
Panoramic view of the entire near-infrared sky reveals the distribution of galaxies beyond the Milky Way. Image credit: Thomas Jarrett, IPAC/Caltech.
On the longer end of the electromagnetic spectrum, infrared and radio telescopes have been around for decades helping astronomers understand more about the universe. But this is only part of the picture. The cold dust that absorbs the visible light to create the dark regions seen through optical telescopes is actually absorbing the light’s energy and reemitting it at longer wavelengths in the submillimetre region.
The first submillimetre camera, SCUBA, was designed and constructed at the Royal Observatory in Edinburgh in collaboration with the University of London. In 1997, it was up and running at the JCMT. Observations of submillimetre wavelengths are typically harder to gather — it takes a long time to image a small portion of the sky in this region. Nevertheless, submillimetre observations have already revealed a previously unknown population of distant, dusty galaxies as well as images of cold debris discs around nearby stars. This latter finding could be an indication of the presence of planetary systems.
A team of astronomers has recently developed the camera SCUBA-2 that can probe the submillimetre region with increased speed and much greater detail. But it’s a touchy instrument. Director of the JCMT Professor Gary Davis explains that for SCUBA-2 to detect extremely low energy radiation in the submillimetre region, “the instrument itself needs to be [extremely cold]. The detectors… have to be cooled to only 0.1 degree above absolute zero [–273.05°C], making the interior of SCUBA-2 colder than anything in the Universe that we know of!”
The infant Universe as imaged in the radio wavelength spectrum. Image Credit: NASA/WMAP Science Team.
The camera is a huge step in observational astronomy. Director of the United Kingdom Astronomy Teaching Centre Professor Ian Robson likened the technological leap between early sub-millimetre cameras and SCUBA-2 to the difference between wind-on film cameras and modern digital technology. “It is thanks to the ingenuity and abilities of our scientists and engineers that this immense leap in progress has been achieved,” he said.
Dr Antonio Chrysostomou, Associate Director of the JCMT, explains that SCUBA-2’s first task will be to carry out a series of surveys throughout the sky, mapping sites of star formation within our Galaxy, as well as planet formation around nearby stars. It will also survey our galactic neighbours and look into deep space to sample the youngest galaxies in the Universe. This latter task will be critical in helping astronomers understand how galaxies have evolved since the Big Bang.
The SCUBA-2 camera is housed on the 15 metre (about 50 foot) diameter JCMT situated close to the summit of Mauna Kea, Hawaii, at an altitude of 4092 metres (about 13,425 feet). It is typically used to study our Solar System, interstellar dust and gas, and distant galaxies.
Source: Revolutionary New Camera Reveals Dark Side of the Universe
The James Clerk Maxwell Telescope. Image credit: www.jach.hawaii.edu
Coronal Mass Ejection as viewed by the Solar Dynamics Observatory on June 7, 2011. A similar type of outburst triggered aurorae during a strong geomagnetic storm in February 1872. Image Credit: NASA/SDO
[/caption]According to a new set of NASA computer simulations, solar storms and Coronal Mass Ejections (CMEs) can erode the lunar surface. Researchers speculate that not only can these phenomena erode the lunar surface, but could also be a cause of atmospheric loss for planets without a global magnetic field, such as Mars.
A team led by Rosemary Killen at NASA’s Goddard Space Flight Center, has written papers exploring different aspects of these phenomena and will appear in an issue of the Journal of Geophysical Research Planets. The team’s research was also presented earlier this week during the fall meeting of the American Geophysical Union.
What are CME’s? Corona Mass Ejections are intense outbursts of the Sun’s usually normal solar wind which consists of electrically charged particles (plasma). CME’s blow outward from the surface of the Sun at speeds in excess of 1.6 million kilometers per hour into space and can contain over a billion tons of plasma in a cloud larger than Earth.
Our Moon has the faintest traces of an atmosphere, which is technically referred to as an exosphere. The lack of any significant atmosphere, combined with the lack of a magnetic field, makes the lunar surface vulnerable to the effects of CME’s.
William Farrell, DREAM (Dynamic Response of the Environment at the Moon) team lead at NASA Goddard, remarked, “We found that when this massive cloud of plasma strikes the Moon, it acts like a sandblaster and easily removes volatile material from the surface. The model predicts 100 to 200 tons of lunar material – the equivalent of 10 dump truck loads – could be stripped off the lunar surface during the typical 2-day passage of a CME.”
While CME’s have been extensively studied, Farrell’s research is the first of its kind that attempts to predict the effects of a CME on the Moon. “Connecting various models together to mimic conditions during solar storms is a major goal of the DREAM project” added Farrell.
When intense heat or radiation is applied to a gas, the electrons can be removed, turning the atoms into ions. This process is referred to as “ionization”, and creates the fourth form of matter, known as plasma. Our Sun’s intense heat and radiation excites gaseous emissions, thus creating a solar wind plasma of charged particles. When plasma ions eject atoms from a surface, the process is called “sputtering”.
The lead author of the research paper Rosemary Killen described this phenomenon: “Sputtering is among the top five processes that create the Moon’s exosphere under normal solar conditions, but our model predicts that during a CME, it becomes the dominant method by far, with up to 50 times the yield of the other methods.”
Images from computer simulations of the lunar calcium exosphere during a CME (left) and the slow solar wind (right). Red and yellow indicate a relatively high abundance of calcium atoms while blue, purple, and black indicate a low abundance. The CME produces a much denser exosphere than the slow solar wind. Image Credit: NASA / Johns Hopkins University
In an effort to better test the team’s predictions, studies will be performed using NASA’s Lunar Atmosphere And Dust Environment Explorer (LADEE). Scheduled to launch in 2013 and orbit the Moon, the team is confident that the strong sputtering effect will send atoms from the lunar surface to LADEE’s orbital altitude (20 to 50 km).
Farrell also added, “This huge CME sputtering effect will make LADEE almost like a surface mineralogy explorer, not because LADEE is on the surface, but because during solar storms surface atoms are blasted up to LADEE.”
Affecting more than just our Moon, solar storms also affect Earth’s magnetic field and are the root cause of the Northern and Southern lights (aurorae). The effect solar storms have on Mars is a bit more significant, due in part to the Red Planet’s lack of a planet-wide magnetic field. It is widely theorized that this lack of a magnetic field allows the solar wind and CME’s to erode the martian atmosphere. In late 2013, NASA will launch the Mars Atmosphere and Volatile Evolution (MAVEN) mission. The goal of MAVEN is to orbit Mars and help researchers better understand how solar activity, including CMEs, affects the atmosphere of the red planet.
