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The Geminid Meteor Shower is the grand finale of astronomical events in 2012 and is usually the most reliable and prolific of the annual meteor showers.
This year we are in for a special treat as the Moon will be absent when the Geminids are at their peak on the evening of the 12th/ 13th of December. This means that the sky should be at its darkest when the shower is expected, and many more of the fainter meteors may be seen.
The Geminid meteor shower is expected to yield in excess of 50 meteors (shooting stars) per hour at peak for those with clear skies, the meteors it produces are usually bright with long persistent trains. If observing opportunities aren’t favorable or possible on the 12th/ 13th, meteor watchers can usually see high meteor activity a day or so either side of the peak.
As well as being the grand finale of 2012, the Geminids are special in another way. Unlike the majority of all the other annual meteor showers the Geminids are thought to be from an object known as 3200 Phaethon – an asteroid not a comet.
To celebrate this long anticipated event, there will be the Geminid Meteorwatch and anyone with an interest in the night sky can join in on Twitter, Facebook and Google+. The event will be an excellent opportunity to learn, share information, experiences, images and more. Whatever your level of interest, wherever you are on the planet Meteorwatch will run for approximately four days. All you need to do is follow along using the #meteorwatch hashtag.
As well as the wealth of information exchanged and shared on Twitter and the other social media outlets, there are helpful guides and information available on Meteorwatch.org so you can get the most out of your #meteorwatch.
To get the ball rolling there is a Hollywood style trailer for the event, purely as a bit of fun and for people of all walks of life to feel inspired and to go outside and look up. You don’t need a telescope or anything, just your eyes and a little bit of patience to see a Geminid meteor.
Caption: A bright fireball meteor on August 1, 2012. Credit: John Chumack.
This will probably be the most simple and easiest guide to viewing the Perseids and other meteor showers you may possibly ever read. The reason why it is so simple is when you are outside you want to concentrate on looking for meteors and not worrying about technical details, which are unnecessary for the casual observer.
First, a LITTLE about the Perseids: The Perseid meteor shower is an annual event occurring every August. They are tiny particles of dust and debris from the tail of a comet (109P/Swift-Tuttle) which planet Earth encounters every year in its orbit around the Sun. When these particles collide with the Earth’s atmosphere, they burn up causing bright flashes and streaks in the night sky. These are known as shooting stars or meteors.
Credit: NASA
To see Perseids (shooting stars/meteors) we only need to do a few simple things.
Plan when you want to look for meteors: Check timings and set aside a good hour or more for observing (away from bright lights if possible). Meteors seldom appear immediately so give yourself a good hour or more to see as many as possible. Late evening and after midnight is a good time for meteor hunting. One of the best time to look, however, is during the dark hours immediately before dawn. There are some good guides with timings, etc. on www.meteorwatch.org, NASA, or Universe Today’s weekly SkyWatcher’s Forecast
Get comfortable: Dress warmly as even in August it can get chilly at night. Find yourself a good garden chair, deck chair, trampoline or place on the ground you can lay a sleeping bag or blanket, as the idea is for you to keep your gaze on the sky for as long as possible. Lying down on the ground or sitting on a reclining garden chair will make this much easier for you. Take with you food and drink to make the evening even more enjoyable.
Where to look: A lot of guides will tell you to look in certain directions at certain times and be far too technical, this is totally unnecessary. All you need to do is look up and fill your gaze with sky for as long as possible (blink and you miss it). Meteors/shooting stars from meteor showers tend to appear randomly all over the sky, they will however originate from a point called the radiant which gives the meteor shower its name the Perseids radiant/point of origin is in the constellation of Perseus, hence the name. You don’t need to look in any particular direction, just look up.
How to look: You do not need a telescope, binoculars or any other viewing aid; you only need your eyes.
What to expect: Don’t expect to see the heavens raining down with fire. Expect to see one or more bright flashes/ streaks of light (meteors/shooting stars) every few minutes. The Perseids can deliver fifty to a hundred meteors per hour at their peak, which is just after the night of the 11th and 12th August through to the 13th and 14th August, be patient and you will see some. Occasionally you may be lucky to see an incredibly bright meteor known as a fireball, these are a real treat. Also, as an added bonus this year, Jupiter, Venus, and the crescent Moon are gathering together in the night sky just as the Perseid meteor shower reaches its peak.
Enjoy yourself and keep looking up, the more you look up the more you will see. When you look away that’s when you miss the best meteor of the evening.
For further information and to join in with the worldwide #meteorwatch on twitter follow @virtualastro and visit meteorwatch.org
A large meteor seen in the sky over the UK, near a rainbow light display. Credit: Mike Ridley.
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On the evening of March 3rd 2012 at approximately 21:40 GMT, an incredibly bright fireball/bollide was seen over the United kingdom.
Many people were outside enjoying a clear evening under the stars, or going about their ordinary business when they spotted the amazingly bright object shooting across the sky. Nearly all of the observations from the public from across much of the country described the object as a very bright fireball traveling from north to south and disappearing low in the sky.
The image above is from Mike Ridley, who said, “I was out tonight photographing the global rainbow display at Whitly Bay and saw this bright light hurtling across the sky. I quickly turned the camera to capture it as it flew overhead. With the naked eye I could see it white hot with an orange tail & really low in the sky. I thought it was a massive firework rocket.”
See two videos of the fireball, below.
Most accounts give a duration of around 10 to 15 seconds and the fireball showed a bright orange nucleus with a bright green tail. There was some fragmentation as the fireball ploughed through the atmosphere.
At present, it is unknown whether any pieces of the object survived and hit Earth’s surface, but there is a high possibility that if it did, it landed in the ocean.
Special thanks to Ninian Boyle astronomyknowhow.com for information in parts of this guide.
March brings us some wonderful sights to see in the night skies for those who are armed with binoculars, telescopes or just their eyes.
The brightest object in the night sky this month (apart from the Moon) is the Planet Venus. Venus and mighty Jupiter have already been providing a treat n the western skies for naked eye observers, but by the middle of the month the two planets will inch even closer. There are other planetary conjunctions this month as well.
The stars of spring are starting to become more prominent and the mighty constellation of Orion sets earlier in the west as the nights roll on. The constellations of Leo, Coma Berenices and Virgo herald the region of the sky known as the “Realm of the Galaxies” more so as the month moves on.
We have Comet Garradd visible all night long through binoculars, as it starts to fade from 7th to 8th magnitude. You can find it near the north celestial North pole near the star Kochab or Beta Ursa Minoris (The little Bear) on the 6th, and the star Dubhe in the Plough on the 21st. Scan this region with binoculars and you should pick it up as a faint misty patch of light.
The Sun continues to become more active as it approaches “Solar Maximum” in 2013 and this is a time when we need to be on our guard for sudden bursts of activity which can result in aurora for observers in high latitudes. Some large geomagnetic storms in the past have resulted in Aurora being spotted as far south as regions near the Caribbean and Mediterranean. Will we get a show like this soon?
Planets
There are going to be some excellent conjunctions this month, as planets and even sometimes the Moon are close together and appear in the same region of the sky.
Mercury. Keep an eye out for the tiny planet Mercury. This planet (closest one to the Sun) is notoriously difficult to see. The best time to try and catch it is on the 4th, low down near the western horizon shortly after sunset. Make sure the Sun has fully set if you plan to sweep the area with binoculars. Never ever look at the sun directly with binoculars, telescopes or your naked eyes – This will damage your eyes or permanently blind you!
Mercury just after sunset - Beginning of March
Mars reaches what we call ‘opposition’ on the 3rd, when it is directly opposite the Sun in the sky from our point of view here on Earth. This is the best time to view the “Red Planet” with a telescope. Try and see if you can spot its ice caps and dark markings. It will need a clear steady sky and a good magnification to see these well, try different coloured filters and even have a go at webcam imaging this amazing Planet. On the 7th the nearly full Moon lies 10-degrees to the south of the planet Mars. You’ll know its Mars by its distinct orange/pink colour.
Mars
Venus & Jupiter bring us the highlight of the month when they appear to be very close to each other and are just separated by 3 degrees on the 15th of March. The brightest out of the pair will be Venus with Jupiter below it and the pair will be an amazing sight – like a pair of heavenly eyes staring down at us. The two planets will be close to each other either side of the 15th, so there should be plenty of picture-taking opportunities. The Moon joins the Venus and Jupiter on the 25th and 26th and the thin crescent Moon will make the show even more stunning.
Venus Jupiter 15 March
Saturn rises later in the evenings in the constellation of Virgo, the rings are now nicely tilted towards us and the planet looks stunning right throughout the month. If you have never seen Saturn through a telescope before, you must see it! It is the most beautiful of all the planets and one of the reasons so many people get interested in astronomy.
Saturn
Moon phases
First Quarter – 1st March
Full Moon – 8th March
Last Quarter – 15th March
New Moon – 22nd March
Constellations
In March Orion is getting lower in the West and setting earlier as the spring constellations of Leo, Coma Berenices and Virgo come into view; this is the “Realm of the Galaxies.”
In the month of March the Earth’s orbit around the Sun means that during the night we see out from our own galaxy the ‘Milky Way’ into the depths of deep space. Because of this, we can see many other galaxies and some similar to our own, each contains hundreds of billions of stars. You will need a good telescope to see these amazing wonders; however a good pair of binoculars will show one or two faint fuzzy patches. Some of these faint fuzzy objects are many millions of light years distant.
A few brighter examples lay in the constellation of Leo the Lion. Have a look for M 95, M96 and M105; these are not far from Mars during March. You will need a dark Moonless night to see them well.
Another trio of galaxies still in the constellation of Leo are M65, M66 and NGC 3628 otherwise known as the ‘Leo Triplet’ A small telescope and a low to medium power should show these objects in the same field of view.
The region of sky within Leo, Coma and Virgo is packed with galaxies and whatever telescope you use, you will be sure to spot something.
For those of you without a telescope, see if you can discern the asterism of the ‘Bowl of Virgo’. This is a chain of five stars in a loose semi-circle pointing towards the ‘tail’ of Leo. The brightest star in the chain is Porrima. South of Porrima lays the brightest star in the constellation, called Spica. Saturn can be found to the east of this.
Long Exposure Photograph of the ISS Credit: Mark Humpage
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If you have seen the International Space Station (ISS) pass over a few times with your own eyes, (here’s our guide on seeing it) you may want to have a go at photographing it.
Photographing the ISS is very worthwhile and gratifying. There are two basic methods; one being easy and the other being a little more difficult. Both methods are incredibly rewarding and good results can be obtained fairly quickly, once you have mastered the basics.
Method 1: Discovery and ISS pass over the UK on March 7, 2011, captured by Will Gater.
You will need a DSLR camera or another type of camera which is capable taking long exposures. Incredibly important is having a tripod or somewhere you can place your camera without it getting vibrations or movement.
Find out when and where the ISS will be passing over your location and choose a part of the sky the ISS is passing through at which you can point your camera.
Experiment with your camera settings, to get colours and exposures correct beforehand and do a couple of long exposure test shots of anything from 15 to 60 seconds. You can do shorter or longer exposures but this is up to you, depending your equipment and how artistic you want to be.
This method will produce a long white streak or line, which will show the path taken of the International Space Station as it passes over. This is the most common method for amateurs.
Method 2: The ISS and shuttle Discovery during the STS-131 mission. Credit: Ted Judah
You will need a telescope, a webcam, and a strong mount or tripod. Set up your telescope and mount, along with webcam with a laptop and make sure of the time and where the ISS will be passing over your location.
In this method we will use the telescope to magnify and see the ISS up close while recording a movie (AVI). We will then stack the frames of the recorded movie in a specialist image enhancing program such as Registax.
Insert your WebCam into the telescope focusing tube using an adapter (available from astronomy stores) and connect the cables to your laptop. When the ISS is due, start recording and track the space station using a finder scope or computerized mount.
The difficult part of this method is tracking the ISS and keeping it in the field of view of the telescope while recording the video file. It is recommended that you set your mount in “Alt/ Az” mode or use a Dobsonian telescope so that you have free movement of telescopes optical tube assembly. You will basically be using the telescope as a giant video camera and you need to keep the ISS in shot for as long as possible.
This method is very difficult as the ISS has been magnified highly while moving very quickly and can be easily lost out of the field of view, or there can be too much movement (shaking) in the video. This method requires much practice.
Once you have been able to get a video of the ISS passing over, you can feed your video file into software such as RegiStax and the program will sort each individual frame, removing bad frames and stacking good frames to create a very clear image.
This method is fantastic for creating close up images with detail on the International Space Station; you can also see docked spacecraft. You can also use this method for trying to image other Earth-orbiting satellites, too.
The ISS and shuttle Discovery as captured -- and annotated -- by Thierry Legault
It would be great to see your ISS photographs, so please send them into us via our Flickr site. Good luck!
The International Space Station Credit: @VirtualAstro
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Most readers of Universe Today are familiar with the International Space Station or “ISS” as it’s often referred to. But just in case you are visiting our site for the first time, the ISS is a huge space station orbiting Earth that serves as an orbital laboratory, factory, testing ground and home; crew members conduct experiments from biology to astronomy, including experiments for prolonged exposure to life in space for future missions to the Moon and beyond.
The ISS is major accomplishment for NASA (US), ESA (Europe), JAXA (Japan) CSA (Canada) and all the countries involved (16 in all). The space station is just over 72 m long by 108 m wide and 20 m high; it is maintained at an orbital altitude of between 330 km (205 mi) and 410 km (255 mi) and travels at an average speed of 27,724 kilometres (17,227 mi) per hour, completing 15.7 orbits per day.
One of the best things about the ISS is that you can see it with your own eyes from Earth! It’s very easy to watch the International Space Station pass over your own backyard!
All you need to do is understand when the ISS is going to be passing over your location and where to look for it in the sky. You can check this by using an ISS pass predictor app or website such as Heavens-Above.
Once you have found out when the ISS will pass over your location, all you need to do a few minutes before the pass is go outside and start looking in the right direction of the sky.
The International Space Station always passes over starting from a westerly part of the sky, but not always from the same point. It can be low on the horizon for some passes and very high others. Most of the apps or websites will tell you what direction in the sky the pass will start and end and how many degrees above the horizon the starting and ending points are. Also included are the highest altitude the ISS will be. For example, if the maximum elevation is listed as somewhere between 74-90 degrees above the horizon, the ISS will be passing almost straight overhead (Just like you learned in geometry, 90 degrees would be straight up). If you aren’t sure about where to look, a good rule of thumb is that your fist outstretched at arm’s length is 10 degrees. If the ISS will be first be seen 40 degrees above the horizon, look four fist-lengths above the horizon. Check apps and websites for where and what track the ISS will take on each individual pass.
When the station passes over it will travel from a westerly direction, heading in an easterly direction. An average good pass can last about 5 minutes.
The ISS looks like an incredibly bright, fast-moving star and can be mistaken for an aircraft. However, the ISS has no flashing lights and it can be much brighter. It seemingly just glides across the sky.
Short passes can last a few seconds to a few minutes and you can see the international space station slowly move into the Earth’s shadow, good bright passes will show the ISS moving across the sky from horizon to horizon.
ISS long exposure photograph over Donnington Castle UK Credit: www.Perfexion.com
The International Space Station usually takes around 90 minutes to orbit our planet, so if you’re really lucky you can get two, or maybe even three or four passes in an evening or morning.
Not only can you see the ISS in the evening but you can also see it in the mornings as both the ISS and Sun are in the ideal position to illuminate the spacecraft at this time. The light we see from the ISS is reflected sunlight.
You can’t watch the ISS pass over during the middle of the day because in the daytime the sky is too bright (although some people with specialized equipment have seen it) and you cannot see the space station in the middle of the night, as it is in the Earth’s shadow and no light is being reflected from it.
The position that the ISS will be in the sky changes every night. The space station does not take the same track or orbital path for each orbit and this change provides good visible passes roughly every 6 weeks in each location on Earth.
Occasionally if a spacecraft such as a Soyuz crew capsule or a Progress resupply vehicle has been sent to the ISS, you will see objects preceding or trailing the station as it moves across the sky. These can either be very close to the station or the distance between the objects can be measured in minutes. To check if there are any other spacecraft with the international space station during a pass, use the pass prediction app, or the Heaven’s Above Site.
Seeing the ISS is an incredible sight! Just remember there are people on board that fast moving point of light!
Good luck! ISS long exposure photograph Credit: Mark Humpage
Special thanks to Ninian Boyle astronomyknowhow.com for information in parts of this guide
This month, the Solar System gives us a lot to observe and we’ll even start to see the ‘spring’ constellations appear later in the evenings. But February still has the grand constellations of winter, with mighty Orion as a centrepiece to long winter nights.
The Sun has finally started to perform as it should as it approaches “Solar Maximum.” This means we get a chance to see the northern lights (Aurora), especially if you live in such places as Scotland, Canada, Scandinavia, or Alaska or the southern light (Aurora Australis) if you live in the southern latitudes of South America, New Zealand and Australia. Over the past few weeks we have seen some fine aurora displays and will we hope to seesome in February!
We have a bit of a treat in store with a comet being this month’s favourite object with binoculars as well, so please read on to find out more about February’s night sky wonders.
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 February night sky and when and where can we see them?
Aurora Looking north from the science operations center at Poker Fla,Alaska. Credit: Jason Ahrns.
The Aurora or Northern Lights (Aurora Borealis) have been seen from parts of Northern Europe and North America these last few weeks. This is because the Sun has been sending out huge flares of material, some of which have travelled towards us slamming into our magnetic field. The energetic particles then follow the Earth’s magnetic field lines towards the poles and meet the atoms of our atmosphere causing them to fluoresce, similar to what happens in a neon tube or strip light.
The colours of the aurora depend on the type of atom the charged particles strike. Oxygen atoms for example usually glow with a green colour, with some reds, pinks and blues. So the more active the Sun gets, the more likely we are to see the Northern (or Southern) Lights.
All you need to see aurora is your eyes, with no other equipment is needed. Many people image the aurora with exposures of just a few seconds and get fantastic results. Unfortunately auroras are “space weather” and are almost as difficult to predict as normal terrestrial weather, but thankfully we can be given the heads up of potential geomagnetic storms by satellites monitoring the Sun such as “STEREO” (Solar TErrestrial RElations Observatory).
Spaceweather.com is a great resource for aurora and other space weather phenomenon and the site has real-time information on current aurora conditions and other phenomenon.
Planets
Mercury is too close to the Sun to be seen at the beginning of the month, but will be visible very low in the south west from the 17th onwards. At the end of February Mercury will be quite bright at around mag -0.8 and will be quite a challenge. It can be seen for about 30 minutes after sunset.
Venus will improve throughout the month in the south west and will pass within half a degree of Uranus on the 9th of February. You can see this through binoculars or a small telescope. On the 25th Venus and the slender crescent Moon can be seen together a fabulous sight. At the end of month Venus closes in on Jupiter for a spectacular encounter in March. Venus
Mars can easily be spotted with the naked eye as a salmon pink coloured “star” and starts off the month in the constellation of Virgo and moves into Leo on the 4th. Mars is at opposition on March 3rd but is also at its furthest from the Sun on the 15th February making this opposition a poor one with respect to observing due to its small apparent size. The planet will still be visually stunning throughout the month.
Mars
Jupiter starts off the month high in the south as darkness falls and is still an incredibly bright star-like object. Through good binoculars or a small telescope you can see its four Galilean moons – a fantastic sight. On the 8th at around 19:50 UT, Europa will transit Jupiter and through a telescope you will see the tiny moons shadow move across its surface. Throughout February, Jupiter moves further west for its close encounter with Venus in March.
Jupiter
Saturn rises around midnight in the constellation of Virgo and appears to be a bright yellowish star. Through a small telescope you will see the moon Titan and Saturn’s rings as well. Saturn
Uranus is now a binocular or telescope object in the constellation of Pisces. On the 9th Uranus and the planet Venus will be within half a degree of each other.
Uranus
Neptune is not visible this month.
Comets Comet Garradd Credit: astronomy.com
Comet Garradd is still on show early in the month — if you have binoculars — and as the month progresses the viewing should improve. You can find the comet in the constellation of Hercules not far from the globular cluster M92. It is about a half a degree away or around the same width as the full Moon. The comet is around magnitude 7 or a little fainter than the more famous globular cluster M13 also to be found in Hercules, so you will definitely need binoculars to see it. The comet is heading north over the course of the month which should mean that it will become a little easier to see. At the beginning of the month you will have to get up early to see it, the best time being around 5:30 to 6:30 GMT. By the end of the month though, it should be visible all night long.
Moon phases
Full Moon – 7th February
Last Quarter – 14th February
New Moon – 21st February
Constellations
In February, Orion still dominates the sky but has many interesting constellations surrounding it.
Above and to the left of Orion you will find the constellation of Gemini, dominated by the stars Castor and Pollux, representing the heads of the twins with their bodies moving down in parallel lines of stars with each other.
Legend has it that Castor and Pollux were twins conceived on the same night by the princess Leda. On the night she married the king of Sparta, wicked Zeus (disguised as a swan) invaded the bridal suite, fathering Pollux who was immortal and twin of Castor who was fathered by the king so was mortal.
Castor and Pollux were devoted to each other and Zeus decided to grant Castor immortality and placed Castor with his brother Pollux in the stars.
Gemini has a few deep sky objects such as the famous Eskimo nebula and some are a challenge to see. Get yourself a good map, Planisphere or star atlas and see what other objects you can track down. Credit: Adrian West
This photo was taken on January 22, 2012 in Fairbanks North Star Borough County, Alaska, US, using a Nikon D5000. The explodey look is due to perspective from looking right up the magnetic field lines. The aurora in the middle of the explosion is pointing straight down at the camera. Credit: Jason Ahrns
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On January 22nd 2012, skywatchers in the northern hemisphere were rewarded with amazing displays of aurora. The cause of these displays was a Kp level 5.67 geomagnetic storm originating from solar activity on the 19th of January, produced visible aurorae throughout the northern hemisphere and viewers as far south as northeast England had great auroral views.
Here is a selection of aurora images and videos taken during the event.
More below!
Aurora over Donegal, Ireland. Credit: Brendan Alexander Brian Horisk adventureart.co.uk hills near Dundee
Callum - AberdeenLooking north from the science operations center at Poker Flats, Alaska. Credit: Jason Ahrns.David WoodfordGerry Mcgegor - over looking John O'Groats & orkney'sGillian C - EdinburghGraham Scott - AberdeenshireLawrie Dryden - KinlossCorinne Mills - Near Dundee ScotlandAndrew Smith - St Mary's Lighthouse Whitley Bay EnglandBrian Smith - Clackmannanshire ScotlandGraham Scott - AberdeenshireJon Porter Kielder - Northumberland EnglandAlan RoweDean Mann - Nethybridge HighlandsBen Hurst - DundeeDavid Breen - Newcastle Upon Tyne EnglandDavid Breen - Newcastle Upon Tyne EnglandAurora Webcam Sweden http://www.auroraskystation.com/live-camera/9/Lee Jennings Cresswell Beach Northumberland EnglandLee Jennings Cresswell Beach Northumberland England
A public “mass participation” push initiated on a UK television program to find planets beyond our Solar System has had an immediate result! On Monday, January 16, 2012 “BBC Stargazing LIVE” began its first of three nights of television programs live from Jodrell Bank Observatory in the UK. The series was hosted by Professor Brian Cox, comedian Dara O’Briain along with a number of other well known TV personalities, astronomers and scientists. There was even a guest appearance via satellite link from Captain Gene Cernan, the last man on the Moon.
As well as the main TV program, there were numerous local events across the UK and the viewers could “mass participate” in activities such as looking for extra solar planets with the citizen science project, Planethunters.org.
The website hosts data gathered by NASA’s Kepler space telescope, and asks volunteers to sift the information for anything unusual that might have been missed in a computer search. People are especially adept at seeing things that computers do not and the BBC Stargazing Live event was a golden opportunity to get many people looking. During the event, over a million classifications were made and 34 candidate planets found on the website in 48 hours.
On the last show of the series on Wednesday 18th January it was announced, that in particular, one planet candidate looks extremely promising, as it has been identified multiple times by PlanetHunter participants.
The planet is circling the star SPH10066540 and is described as being similar in size to Neptune, circles its parent every 90 days and is about a similar distance from its parent star as Mercury is from our Sun. It could be described as a hot Neptune.
Chris Holmes from Peterborough UK and Lee Threapleton also from the UK found the planet by searching through time-lapsed images of stars looking for the periodic dips in brightness that result every time a planet passes in front of (transits) one of those stars.
Credit: planethunters.org
A transit has to be observed several times before a planet will be confirmed. For the orange dwarf star SPH10066540, five such events have now been seen in the Kepler data making it a strong candidate for an extra solar planet.
“There’s more work to be done to confirm whether these candidates are true planets,” wrote the PlanetHunters team on their blog, “in particular, we need to talk to our friends on the Kepler team – but we’re on our way.”
The NASA Kepler space telescope, launched in 2009, has been searching a part of space thought to have many stars similar to our own Sun.
You can try and find a new planet too by visiting planethunters.org it is incredibly simple and easy to do and requires no previous knowledge of astronomy.
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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!)
