On 2March 2004 the European Space Agency (ESA) launched an ambitious and exciting robotic explorer into space, and you probably have heard its quite pretty name mentioned a lot lately. It is the trailblazing Rosetta spacecraft and it has been given a task that has seen many before attempt and fail; to get close to and learn more about the earliest believed building blocks in the Solar System, the comets! This patient and quite heavy 3 tonne vehicle has been on a complex journey in order to time its encounter with the lucky comet that will hopefully reveal all to us, comet 67P/Churyumov-Gerasimenko.
During its ten years in space it has bounced about the Solar System, circling the sun nearly four times as well as chancing its luck traveling through the Asteroid Belt twice, as well as doing some maverick manoeuvres using fly-bys of Mars and Earth to help give a little boost in speed in order to reach its destination at the right time. In May 2014 Rosetta started to apply the brakes with its thrusters so the ten year mission would not end up with Rosetta scorching past the comet and instead find itself sharing the comet’s orbit. The mission so far has been highly successful. After being in deep hibernation in space for two and a half years, Rosetta burst back into life on 20 January 2014 and from 6 August 2014 it has found itself comfortably orbiting comet 67P and keeping it company on the way into the inner regions of the Solar System. Not content with a nearby seat to the comet show, ESA have a little package hidden on Rosetta. A little lander called Philae which will try to land the on snowy dirtball on 12 November 2014.
But the secrets of the comet are not just locked away until 12 November. The Rosetta spacecraft has now been orbiting comet 67P for several months and it has been sending back some of the best images the world has ever received of a comet as well as raising some eyebrows in disbelief along the way!
It’s making scientists go ‘quackers’!(pardon the pun)
Images of 67P in the early days from ground based telescopes led the world to believe its nucleus to be the normal potato-like shape of the average comet but since arriving at the comet, Rosetta have revealed a much odder ‘disney’ like shape! In order words instead of resembling a potato it looks more like a rubber duck! One end of the comet is significantly smaller than the other (the larger being the duck body and the smaller being the head) with a considerably narrow bit in the middle (the duck neck). From close observation the smaller end measuring 2km by 2.5km by 2.5km and the larger end being 4.1km by 3.2km by 1.3km with a mass of 10 billion tonnes but due to the odd and distorted shape it has taken a while for this information to come out.
Comets are big dirty snowballs….aren’t they?
One of the strangest things so far that has been observed on the comet is its dryness. Comets have often been believed to hold the secret to how life started here on Earth and also hopefully have the information locked away within them to whether or not life is unique to us or if it is possible that comets have furnished other planets with the essential building blocks of life, particularly water or ice. So due to the lovely tails that form when comets come close to the sun which has been widely believed to be melting ice as well as other gases, the assumption has always been that comets would be made of or have a lot of ice on them. But comet 67P looks extremely dry! Scientists had hoped to see lots of patches of ice on the chilly visitor as it is still a good distance from the Sun but instead there is nothing but lots of dry darkness to gaze at. So, so far scientists are a little confused and hopefully when the little lander Philae latches itself on the comet’s surface it will have a front and centre seat to the creation of the comet tail and see how the particles on the comet react when it gets closer to the Sun.
You may need to look twice!
As well as being void of icy patches on its surface, comet 67P is not exactly bright, more so it’s dark, extremely dark, it is actually darker than charcoal and extremely unreflective. As stated above scientists believed that comet 67P was going to a glorious BRIGHT ball of ice due to the fact that it is not close enough to the warmer regions of the solar system to start melting but alas it is duller than a rock! (and less reflective than a rock too!) So it should definitely be interesting to see if it begins to “shine” as it gets closer to the Sun.
Every day comet 67P is getting closer to the sun and there have already been reports of activity beginning in early October with jets of gas and dust spotted sprouting from the dull and dark object’s surface! They have even discovered a pyramid-like boulder on the comets surface that they nicely named Cheops after the largest of the Giza Pyramids in Egypt, obviously trying to be ironic considering this rather ragged lump of rock is only 25 meters high! All this has been only observed so far, so the countdown until the comets ‘harpooning’ with the little lander Philae is obviously desperately nail-biting for the scientific community and world. Fingers crossed that we are less than a month away from finding out the secrets of the early Solar System!
(article by Kerry Scullion, Education Support Officer )