The bits inbetween..

I thought this morning about covering Comet Swan in today's post then figured I'd talk about meteorites instead... and then thought why not cover the 'minor bodies' (asteroids/meteorites and comets) in general?

Comet Swan should be at about its brightest (magnitude ~6) this week and is already good enough for binoculars. Having never spotted one before (somehow I missed both Halleys' and Hale-Bopp), it may be one I look out for - since due to its orbit, it's destined never to return. With the aid of these diagrams you should be able to find it with a little luck.

There's a fanastically gorgeous picture on the APOD website of Comet Swan.

Moving on (slightly), I'd dearly love to be able to carry out my dream PhD project on the effects of 'space debris' (for want of a better term) on Earth's climate and its multitudes of species'. It's such a rich field to be able to research in. Comets, asteroids and interstellar dust all have their part to play in the evolution of the Solar System and our 'pale blue dot'.

The fact that our local space isn't empty - despite looking like it is - can be seen easily enough when we witness zodiacal light (the reflection of sunlight at dusk upon interstellar dust) or when we look at diagrams of asteroid locations. Populations of asteroids crop up all over the place other than the asteroid belt. We also have the Centaurs, the Plutons (which are in 3:2 resonance with Neptune (as is Pluto)) and a number of other populations including scattered disk objects. We know that asteroids, meteorites and comets have a tendency to hit planets, moons and each other from looking at any body with a surface (and even sometimes without, thinking of Comet Shoemaker-Levy 9). These impacts are evidenced by the craters they leave behind especially on worlds believed geologically 'dead' like our Moon but they also have their part to play in our being here. Without these impacts, we'd likely have no Moon; and no Earth either...

Crater formation via comets & asteroids has three main stages - compression, excavation & modification. In short, the whole crater-forming process can last from a few seconds to a few minutes (even the Chixculub crater was believed formed in around 3-4 minutes). That's an extremely short timescale when we consider the geological age of the Solar System being at around 4.6 billion years.

The important issue here is the large number of "Potentially Hazardous Asteroids" (PHAs) that are orbiting near to Earth. These are known to cross Earth's orbit at various times and so far there are believed to be about 400 of these...

While the Chixculub asteroid (approximately 10km diameter) and the mass extinction of many species (including the dinosaurs) may be under some debate about exactly what happened 65 million years ago, there can be no doubt that if we were struck by a large asteroid it'd do considerable damage to the planet.

Some of the effects:
1) Vaporisation of any species/animals in the reasonably immediate vicinity (perhaps up to 100km away for a 10km land-based asteroid) and extinctions & death much further out that this.
2) A large enough meteorite would bore a hole in the atmosphere and large amounts of matter from the impact process would be sucked back up into the temporary vacuum and high into the Earth's atmosphere eventually leading to the possibility of a 'nuclear winter'.
3) Some of the ejecta thrown up by the impact may reach escape velocities and 'rain down' on other areas of the planet. These 'spherules' would be extremely hot and may cause forest fires and the burning of other organic matter. Larger pieces of ejecta & rock fragments would be melted into aerodynamic, 'glassy' shapes called tektites - the passage of these through the atmosphere would likely heat it up also.
4) If the impact was into a large body of water, such as an ocean, we'd be likely looking at a devastating tsunami.

All of these things are clearly troublesome... and worth investigating further. A few years down the line this is what I hope I'll be writing about as part of a larger project.

And back here on Earth...

..Expedition 13 and Iranian Space 'Tourist' Anousheh Ansari have touched down this morning at about 1:13AM. The landing was shown live on NASA - although I've not been able to view it yet I do intend to as soon as I can.

I first read about Anousheh in October's Astronomy Now and found her blog a day or so later. By this point she was halfway through her journey so I had a little catching up to do.

When I first heard that people were able to pay to see Space or visit the ISS I was a little jealous, I'll admit! But as I read on, I felt pleased to be able to share in her experience with other readers many of who were people with good intentions, hopes and dreams. I think perhaps that this is something that can be shared so well by anyone with a computer.. and without the blog we'd have had no idea how amazing the journey would be or how it feels to be weightless in the ISS. Or even what space 'smells' like. Or how you feel when you see all those sunrises and sunsets each day and our home spinning beneath you while you watch from orbit.

Anousheh's shared with us all that and more. It makes you appreciate those who work on the International Space Station and sends out messages of hope and understanding for a better future... and it sends them worldwide.

Her journal is here:
http://spaceblog.xprize.org/

So we have to start from somewhere!

Having already been a student for a number of years, I figured perhaps it was time to get a career rather than just having a job. Astronomy has been my hobby since I was about ten years old and after taking A level Physics & Maths at college I moved into the Astrophysics field at University.

Since getting a job I've spent a number of years with the OU dabbling with various courses, some of which I lost interest in pretty quickly. Exoplanets brought me back on track and back into astronomy and I'm about a month away from my first exam in quite a few years - but I'm not letting that hold me back!

I've always wanted to research or write. I just didn't realise it until just over a year ago. Science and Science Fiction have both always been something of a love and I entered a competition to write 50 thousand words in a month last November (over at http://www.nanowrimo.org). I managed a little over 63 thousand with 5 days to go and the only reason I stopped was that the story reached the end.

What I found fascinating was not the words that came out, although they kept coming and coming as the novel practically wrote itself, but it was more the research I did that went alongside it. I spent hours poring over Kurzweil, Sagan, Kaku and a number of other authors. I read about Technological Singularities, Type X civilisations, dyson spheres, possible habitable worlds, Greek Mythology, the Aztecs and Wikipedia, the Amazon Marketplace and Google became my greatest friends.

I'm pleased to be able (thanks to the internet), in this day and age, to research, read and wile away the hours catching up and keeping up with the things I've studied in the past. From star & galactic physics, through relativity and quantum mechanics and onto Titan, astrobiology, cryovolcanism, solar system formation and many other things besides, it seems like hardly a day goes by where there isn't something new in the news. A few days ago it was the new transiting planets WASP-1b and WASP-2b as well as the cork-density HAT-P1b, this morning I was reading about methane lakes on Titan and large-star formation.

Who knows what'll come tomorrow?