An update on Comet ISON!

The comet had been visible in the Southern Hemisphere before passing the Sun but since the 19th November it has been very difficult to see as it has risen just before the Sun. After it had passed the Sun it would be rising just after the Sun rise and setting before the Sun set, in the southern hemisphere so hence we would not have been able to see it.

At around 6:44am our time this morning the comet reached perihelion (its closest approach to the Sun) where it broke up and then something continues on – it might just be gravel and dust or there might stay a chunk of rock big enough to stay comet like. But now only time will tell if it is big.  This goes to prove that although we certainly know a lot more about comets than we did before – there is a lot more that we do not know.  Many have pronounced Comet ISON as already being dead and it certainly will not reach the brightness and spectacular display that had been predicted – but as Mark Twain is often quoted: “Rumours of my demise are greatly exaggerated.”  Something emerged from the sun after Comet ISON made its closest approach today. Is it ISON? Both professional and amateur astronomers are analysing images from NASA satellites to learn more about comet’s fate. Northern ground based observers may have to wait until around the 9/10 of December now to see if there is anything to see. But they will not get the amazing views that we were all hoping for.

However, at every single opportunity it could find, Comet ISON has done completely the opposite of what was expected, and it certainly wouldn’t be out of character for this dynamic object to yet again do something remarkable. Even if the comet broke up, it offered a very rare opportunity to see how one of the oldest objects in the solar system interacted with the Sun’s magnetic field and its behaviour in the sun’s magnetic field will help scientists understand more about both comets and the Sun. This  was the first comet in recorded history which has come from so far away and passed so close to the sun, passing the sun at a distance of around 1.6 million kms that has been so well-studied and observed.

So we wait and see, this has been one of the most well observed, followed and commented in social media worldwide. A fleet of spacecraft watched ISON plunge toward the sun, including NASA’s STEREO satellite, the European Space Agency/NASA SOHO spacecraft and the Solar Dynamics Observatory. The Hubble Space Telescope should be able to take a close look in a couple of weeks if it did indeed survive.

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The photograph above is from the NASA SOHO Space Telescope’s LASCO C3 camera showing a fragment emerging from the other side of the Sun about 3 hours after perihelion.

The picture below is taken this at 00:42UT 1 December 2013 and shows the remnants of the comet as it leaves the SOHO LASCO C# camera’s field of view.

Lyrids Meteor Shower, peakings around tonight April 23rd.

Head out early tomorrow morning between midnight and dawn to catch the Lyrids Meteor Shower.

The Lyrids radiant is close to the constellation of Lyra (a harp). The constellation rises just after midnight in the southern hemisphere and moves across the northern sky. The Lyrids meteor shower is best viewed after midnight o well before sunrise on 23/24th April. Point your feet towards the northern sky and look about 45 degrees above the horizon. You should see a really bright white star there – this is the blue white star Vega. This shower is caused by the Earth’s atmosphere passing through the dusty pebbly debris left over from Comet Thatcher and has been known to produce spectacular meteors.

So what is a meteor? As a comet (which is a large ball of rock and ice from the outer Solar System) passes by the Sun they become quite heated up and they begin to shed gas, ice, dust particles and rocks which we see as the comets tail. This is left behind as the comet continues on its journey around the Sun.  If the comet’s orbit intersects that of the Earth’s orbit some of material strikes our atmosphere and we see a meteor.

Comet Thatcher also known was discovered by an American amateur astronomer A.E. Thatcher in 1861. This comet was the brightest in over half a century and both head and tail were visible together in broad daylight. Every spring for at least the past 2,700 years, Earth has passed through the trail, thrilling countless sky watchers with the sight of flaming dust and grit. In 1803, it was reported that it looked as if the entire sky was alight with flaming stars.

The Lyrid meteors strike our atmosphere about 95 kilometres above the earth and at speeds of around 49 km/sec or 175,000km per hour and can burn up in some pretty amazing fireballs.

Typical meteoroids which is the name given to meteors before they hit the atmosphere – range in size from grains of sand to walnuts. The bigger they are, the brighter. A meteor that actually hits the ground – a rare event fortunately is called a meteorite.

So if you want to have a look –  find somewhere away from street  lights and other bright lights where you can see clearly to the north and east. head out early in the morning either just after midnight – although the Moon will make it harder to see some of the dimmer meteors o around about  3:30 to 5 a.m. toting a thermos of hot chocolate, tea or coffee. Make sure you’re suitably rugged up for the weather and get yourself all comfy in a reclining lawn chair, banana lounge or under a blanket or sleeping bag. No special equipment required.  Look towards the North and enjoy the beauty of the early morning sky and see how man meteors you can see.

Mission to Land on a Comet

Europe’s Rosetta spacecraft is en route to intercept a comet– and to make history. In 2014, Rosetta will enter orbit around comet 67P/Churyumov-Gerasimenkoand land a probe on it, two firsts.

 Rosetta’s goal is to learn the primordial story a comet tells as it gloriously falls to pieces. Comets are primitive leftovers from our solar system’s ‘construction’ about 4.5 billion years ago. Because they spend much of their time in the deep freeze of the outer solar system, comets are well preserved—a gold mine for astronomers who want to know what conditions were like back “in the beginning.”

 As their elongated orbits swing them closer to the sun, comets transform into the most breathtaking bodies in the night sky. A European Space Agency mission launched in 2004 with U.S. instruments on board, Rosetta will have a front-row seat for the metamorphosis.

 At the moment, Rosetta is “resting up” for the challenges ahead. It’s hibernating, engaged in its high-speed chase while fast asleep.

It will be woken up on or around New Year’s Day 2014, to begin a months-long program of self-checkups.

 If all goes well, in August that year, Rosetta will enter orbit around 67P’s nucleus and begin scanning its surface for a landing site. Once a site is chosen, the spacecraft will descend as low as 1 km to deploy the lander.

 The lander’s name is “Philae” after an island in the Nile, the site of an obelisk that helped decipher—you guessed it—the Rosetta Stone.  Touchdown is scheduled for November 2014, whenPhilaewill make the first ever controlled landing on a comet’s nucleus. Because a comet has little gravity, the lander will anchor itself with harpoons.

 Once it is fastened, the lander will commence an unprecedented first-hand study of a comet’s nucleus. 

 Meanwhile, orbiting overhead, the Rosetta spacecraft will be busy, too. On board sensors will map the comet’s surface and magnetic field, monitor the comet’s erupting jets and geysers, measure outflow rates, and much more.  Together, the orbiter and lander will build up the first 3D picture of the layers and pockets under the surface of a comet.