Wednesday, 27 May 2009

Messenger and Mercury


A couple of months ago the NASA Space probe Messenger made another fly-by of its target planet Mercury. Messenger is the only mission after the Mariner probe in the late seventies to visit Mercury. However Messenger is different. It is designed to go into orbit around Mercury, and run a complete mapping of the planet. Whereas the Mariner probe simply flew past taking some quick snaps as it went. The mapping aspect of Messenger’s mission should begin in 2011, but until then Messenger must make several fly-bys of Mercury, so it will be capable of getting into the correct orbit. And it is one of these build up fly-bys that happened a couple of months ago. During this Fly-by Messenger revealed previously unseen parts of the Mercury surface and, made a few surprised discoveries. But first here is a brief run down of are present knowledge of Mercury.
Mercury is the closest planet to the Sun that much is certain. There was a brief stint in the early 20th Century, when people believed there was a planet closer in called Vulcan, but that that was later disproved. Mercury is officially the closest planet to the Sun.
Mercury is also known to be very very hot, with the dayside of the planet reaching temperature as high as 167 Degrees Celsius. Mercury as no atmosphere to speak of, except a very tenuous cloud of trace gases known as an exosphere. The exosphere contains trace amounts of elements such as Calcium, Oxygen and Potassium. Know doubt the remains of countless Comet impacts billions of years ago. Added to this there is a large amount of Hydrogen and Solar particles, certainly the by products of the constant stream of Solar wind hitting the planet.
The surface of Mercury is best described as ancient, with no current geological activity occurring today. Dead in other words .The main surface feature seen is impact craters. Most billions of years old, caused by the impact of Asteroids and Comets at the end of the late heavy bombardment, (Final stage of main solar system formation). And it is one of these impact craters that holds the title of largest crater in the solar system. It is called the Caloris Basin and has as a diameter of over 1500Km! So large was this impact that it forced up the surrounding are to form a mountain range 2 Km high. Other crater features on Mercury are called chain cratering. Chain cratering is formed when a planets gravity rips apart an object say an Asteroid or comet, and the subsequent fragments impact the planet or it's moon, like a chain of bullets from a machine gun. As seen right. This is seen on many planets and moons including mars and Jupiter's moon Calisto.
Mercury is very special terrestrial planet, because besides Earth it is the only other with a magnetic field. The magnetic field is small at only 1.1% that of the earth's, but even that is too much as Mercury is predicted to be completely solid. And therefore incapable of having a molten magnetic field generating core, like the earth.
It is at this point that we return to messenger, after messenger made it's fly-by scientists analysing the data made tantalising discoveries, that may challenge are knowledge of Mercury. And perhaps more intriguingly pose new questions. Messenger imaged previously unseen parts of Mercury with it's cameras and sensors and, found near the poles and around other deep craters large amounts of Water present in the exosphere. Now this was completely unexpected. And scientists now believe this might mean that at the bottom of these craters, some of which are in permanent darkness there might be water ice mixed in with the soil. Not a ice cap worth but more than a trace! This Ice may have arrived from impacting comets, the like of which created the Caloris Basin. As well as this Messenger provided visual evidence on the previously unseen far side of Mercury, of supposed volcanic activity! Which may indicate recent geological activity and, perhaps a still molten core which could finally put to the rest the source of the unexplained magnetic field.
Of course Messenger is an on going mission and it's discoveries are far from over, so if your interested check out there homepage below. I'm sure however that after Messenger is finished Mercury might prove to be not so dead after all!


Monday, 25 May 2009

Voyage of Discovery


The Voyager space craft need know introduction. These twin 700Kg probes were the first ever to visit all four gas giants and, are as of 2009 the most distant Human objects ever built. They are currently at a distance of 10.095 Billion miles from the Sun, on the very edge of the Solar System itself. Approaching the Heliopause and interstellar space. The Heliopause is the region marked out by the solar wind, and is essentially a bubble encompassing the solar system. Of course the History of the Voyager probes is a long and illustrious one.
Launched in 1977 the voyager probes were heading for the outer planets thanks to Newtonian mechanics. It had been calculated that a space probe with conventional rocket fuel could go no further than Jupiter. So a new method was needed if Voyager stood any chance of getting to the furthest reaches of the Solar System. Enter Gravity assist. Gravity assist is a convenient way of getting between planets with out the need for massive fuel stores. It works something like this, if you fly past a planet e.g. Jupiter at the correct angle the planets gravity takes the space robe and, shoots it off in a different direction with an increased burst of speed. Also conveniently at the time of the voyager launch in the seventies, all four gas giants were in a rare 150 year planetary alignment. Which meant that by using gravity assist if the space craft got the correct trajectory as it left each planet, it would be shot of for an encounter with the next planet out and so on.
So with a viable way to get to the outer planets voyager was off!
Voyager 1 reached it's first Gas giant target of Jupiter in march 1979. 2 years after launch. Voyager's closest approach was at a distance of 217,000 miles. Voyagers pass revealed incredible detail about Jupiter it's moons and atmosphere. Among many discoveries Voyager imaged very faint rings around Jupiter. Imaged with unparalleled detail the atmosphere of Jupiter. And perhaps most importantly showed that the four galleon satellites were far from dull! Io was shown to be more active than Earth with many sulphurous volcanoes. And Europa was discovered to have a entire water ice covering, which perhaps covers a warm liquid water ocean! which maybe could have black smokers (volcanic vents), that provide home to microbial life! A lot of speculation there but it's not completely impossible. After the huge success of the first fly by the stage was set for Saturn.
The gravity assist with Jupiter was successful and in February of 1980. 3years after launch Voyager arrived at Saturn. This time Voyagers closest approach was from 77,000 miles. At this distance Voyager unveiled complex structures in Saturn's expansive rings, analysed the Saturnian atmosphere. And again showed that Saturn's moons were surprisingly active. Titan was unique in that it was proved to be the only moon with an atmosphere. And Enceladus had Ice geysers ,that were and still are so prolific they contribute to the ring system around Saturn!
The next fly by was with the planet Uranus (No puns!). Voyager passed Uranus in January 1986, at a distance of 81,000 km. Sadly Uranus was fairly bland and there was little to see in it's Methane clouds. This was a major disappointment for the mission scientists. But Neptune was still to go.
The Final planet in Voyagers mission was Neptune, which was passed in August 1989. Nearly 20 years after the original launch. In contrast to Uranus Neptune was much more interesting. Like Jupiter Neptune was discovered to have a great dark spot and, the fastest winds in the solar system clocked at nearly 1000 mph! Also Neptune's largest moon Triton was imaged with Nitrogen geysers miles high! Such was the frigid temp of this moon, that Nitrogen which makes up the gas of are atmosphere on Earth is frozen solid ice.
Voyager now passed all the planets and with no possibility of reaching Pluto drifted of into interstellar space. It's last image of the solar system was a sort of “Family portrait” ( to right)taken in 1990, with all the planets visible and Earth less than a pixel across!
So that was a brief history of the Voyager probes and there amazing journey to the very edge of the Solar system. The voyager probes now at the very limits of communication with earth, will continue to drift into the void of interstellar space in silence. And in roughly a few million years it is believed they will pass some of the nearest stars!
Thanks for reading.


Sunday, 24 May 2009

Greatest living Britain?


Well as the title indicates is this the greatest living Englishman. Note I didn't put is this the greatest Englishmen ever, because if I did we almost certainly be lost in a sea of Titans such as Brunel, Babbage, Shakespeare or Queen Victoria. But anyway back to the original point is this the greatest living Britain? Of course I dare say some people may never have even see this guy before and think “Who!”. So to anyone who doesn't know this is the face of Tim Berners-Lee. Berners-Lee is a British computer scientist, credited with the invention of the World Wide Web or internet!
Briefly I will tell some of the story of how he came to invent the web and change the world. Before then returning to to the original question.
So in the early eighties the scientists at the Organisation Européenne pour la Recherche Nucléaire (CERN for short), which is now home to the large Hadron Collider. Were faced with a big problem, all the scientists working on different aspects of physics or Quantum mechanics, had know way of posting there findings and keeping each other up to date. So such was the rapid progress of there field. So to solve this issue they brought in a British computer scientist, a one Tim Burners-Lee. So Tim took a NEXT computer to Switzerland (headquarters of CERN) to sort out the problem. The NEXT computer for anyone interested was developed by Steve Jobs of apple fame and, ran a UNIX-based operating system. That last bit was a little beyond me, as I am quite computer literate yet when it comes to the overly technical side am a bit useless!
So let's return back to Burners-Lee. Now while in Switzerland Tim devised a brilliant way of allowing all the separate scientists machines to talk to each other, and share information without actually being physically connected. In a sort of digital web. To do this he created a “Language” all the machines could understand, called Hyper text transference protocol or HTTP for short. After that he created the first web server that could take all these HTTP files from the varying scientists and, have them stored and then brought up at will by another scientist somewhere else. He called this web server after much deliberating the World Wide Web or WWW. The WWW Became the first ever web browser and in a way the first ever website. Capable of bringing up text from all over the CERN sight and then allowing it to be read by any other CERN scientist somewhere else. Problem solved!
Of course I'm sure you don't need me to tell the rest of the story. Of how the WWW spread from CERN and know connects the Human race like never before.
So I have at least told you how Burners-Lee created the web and how it spread out to the rest of the world. But back to the original question is he the greatest living Britain? Well he sure as hell has my vote! Put it this way I can't think of anyone in living memory who has so changed the way Humans live , for instance without him I wouldn't be typing this now and you wouldn't be reading it! The Internet as allowed us to do things unthinkable a mere century ago. For instance from my desk I can check the stocks in Tokyo, or send information to a colleague in New York without even having to so much as move. The internet as quite literally changed everything!
I personally believe Tim should be much more widely know than he is and should receive WAY more recognition than he does.
So Tim Burners-Lee greatest living Britain? YES

Friday, 22 May 2009

Missing link?


I am sorry again for the gap in time since my last post, but I have been quite busy. But thankfully I am now on holiday for a couple of days, so I may be able to produce a few more posts.
Anyway with that apolgetic note out of the way back to the subject of this post.
As I'm sure you may have seen on the news or read in the papers, palaeontologists believe they have at last found the fabled missing link! The missing link in case you don't know is the common ancestor that both apes and humans share. It is the species where Humans and Apes slit from each other and went down there different evolutionary paths, leading to the present day. The missing link is significant because it is final indisputable proof that Charles Darwin's theory of Evolution is correct and, that man did indeed evolve from apes!
But could the fossil above be it?
Of course the media have naturally over blown this story and, of course as far as there concerned THIS IS DEFFINELTY THE MISSING LINK! But really.
The fossil is a 47 million year old primate, discovered in Messel Germany. Officially known as Darwinius masillae, it is the fossil of a Lemur like creature called Ida shows. The fossil has surprisingly Human features. It has opposable thumbs and fingernails instead of the normal primate claws. Scientists also say the cat sized mammals hind legs offer evolutionary evidence that shows how primates adapted to walk on there hind legs, the breakthrough that will finally vindicate Darwin's theory of evolution.
Sadly I am not a palaeontologist and therefore am not very familiar with this branch of science, so I'm sorry that I was unable to provide you with more information. But if your interested a documentary will be airing on the History channel this week, which I for one will be watching.
One thing is certain however there is bound to be a lot more news time given over to this area of science, which obviously must be good.
I'm not sure what my next blog post will be on but I am aiming for something Astronomical

Monday, 4 May 2009

Twitter followers


Just briefly sometime between last night and today I passed the hundred follower mark!
So thankyou to all my followers and to anybody who has read by blog.

Sunday, 3 May 2009

One life

I am going for a nice and cheery subject today. Death! Now please feel free to not to bother to read this, as I am sure the last thing you want is to be depressed by a guy who just likes to ask awkward questions. Hey it's compulsory for Astronomers/scientists to ask awkward questions, in fact it should be compulsory for everyone to ask awkward questions. Life would be much more interesting!
So back to the topic of the day. Death is a idea that as plagued mankind for eternity, raising such irritating questions as What happens when we die? Or even more irritatingly is there a Heaven? Of course philosophers have grappled with such conundrums for quite a while, so I doubt I will help proceedings. But anyway let's have a go.
Of course as a scientist and a person who regards himself as fiercely logical. Nothing happens when we die. Your organs stop and your mind shuts down like the windows (or mac if you prefer) computer and, your finished. Well not quite your kind of recycled by the universe and your atoms are reused, but overall the Human is finished. And the next question Is there a Heaven/life after death? Well again this one is continuously debated by theologians the world over, so my humble opinion pales into insignificance. But I personally believe that there is no life after death. I simply can't see why there would be some special reward or punishment for one insignificant species, on a insignificant plant in the depths of a typical Galaxy. Of course I might be completely wrong! And of course you are perfectly entitled to disagree with me, in addition to this don't assume I am against any religion. I have the up most respect for all religions and people in them.
Briefly I will side track to a little story about this subject. Somebody asked me “If you don't believe in life after death aren't you scared” To which I answer no. I only have a brief blip on this planet and subsequently believe that I should enjoy every second. And try to be constructive with my blip of seventy or so years. And if there is or isn't something there what's the point in worrying about it, as either way you only depress yourself.
Oddly I have just thought of something while listening to the John Lennon song Imagine. If there was proof that there was no beyond (Heaven/Hell), this could be quite good for mankind. Bear with me. If we realised that we had only one life and, that was it. Human behaviour would almost certainly change, there would probably be no more wars or senseless violence. As I hope mankind would consider it unacceptable to end another persons brief stay in this amazingly remarkable world. And as well as this people might finally be able to put aside their petty differences, entering into equality and peace. As life quite literately is too short!
Wow I have amazed myself by managing to end a miserable subject on something reasonably nice.
Thanks for reading and, more Astronomy based blogs will be coming soon.


Saturday, 2 May 2009

Sky at night tribute


It has been a reasonably long length of time since my last post, so here is a new one for anybody interested. The Sky at night is to anybody interested in Astronomy a crucial part of it's fabric. So here is a brief tribute to the Sky at night TV show.
Just briefly I will give the programs history. The Sky at night started in the Summer of 1957, months before the first ever satellite Sputnik went up. So the program is in fact older than the space age. Over it's 50 year run the sky at night as covered many famous astronomical events, from the first satellite,to the first man on the moon, the launch of Hubble and the rather disappointing total solar eclipse from England. Added to this the entire 50 years as been presented by one man. The world famous Sir Patrick Moore.
Now over this time The sky at night as had many notable guests. From Carl Sagan to Fred Hoyle of steady state theory fame. Added to this there have been some recent regulars, including Dr Brian May (From Queen). And more recently Chris Lintott, who started to assist Patrick Moore in presenting as his mobility deteriorated. Just to shamelessly name drop again I am very pleased to have met Chris Lintott and, hear a talk he gave last year.
As part of the shows appeal is it's content, which due to Astronomies always progressing nature as never stagnated. As well as covering the new events in Astronomy such as space probe launches and, new scientific discoveries the Sky at night as covered the more theory based aspects of the subject. Such as Special/General Relativity,the Big Bang and Cosmic microwave background (CMB).
The Sky at night as also influenced many young people to get into Astronomy. Me for a start I used to watch it as a kid and, found it fascinating! And that is what I think is part of it's appeal. Patrick's endless enthusiasm/knowledge of the subject coupled with the amazingness (not a word but never mind) of the subject. Certainly have and will continue to make The Sky at night a huge success!
So that is my brief tribute to the Sky at night.