Tampilkan postingan dengan label Abiogenesis. Tampilkan semua postingan
Tampilkan postingan dengan label Abiogenesis. Tampilkan semua postingan

Kamis, 10 Februari 2011

Thursday's wonder

Whoa. This is where stars are born. This is a new image of the North America Nebula from NASA's Spitzer Space Telescope. You can see the massive full size image here. Why is this important? - in all likelihood our Sun and its planets formed in a nebular cloud very much like this one.

Each little pinpoint speck of light in Spitzer's image is a young star at some particular point in its development., and haven't even become true stars yet—that only occurs when thermonuclear fusion kicks off in their cores. Others have begun their stardom, but are still sheathed in spherical cocoons of gas and dust, shells of material that will gradually grow puffy and vaporous from the inner star's light and heat, until they whisper away on stellar winds. Many of these points of light are ringed by thick accretion disks of material that formed from the angular momentum of their initial gravitational collapse. Sometimes parts of the disk get sucked too close to the star, and are shocked into plasma and spun away and out from the star's poles in powerful collimated jets that can sculpt and shape the surrounding gas and dust into abstract whorls and tendrils. And, in the background, almost unnoticed against all the stellar fireworks, in all probability planets are slowly and surely forming. Perhaps, on a few them, the seeds of life are already being sown by comets and meteorites, the infalling detritus of star formation delivering water and complex chemical compounds brewed in the stellar clouds. Some are still undergoing their initial gravitational collapse.


I tried to find a website that could explain where the  North America Nebula was in easy to understand terms and found just what I was looking for here. Unfortunately I then kept zooming out until my head exploded.

Kamis, 13 Januari 2011

Extreme Planet Makeover

Well that's very topical. In a post to BoingBoing today is a link to NASA's 'Extreme Planet Makeover' website where you can design your own planet and then assess it's chances for life. You set the parameters for the planet and then click on the planet top find it assessed into one of a number of categories. As the BoingBoing post points out though:

If it seems like there's only a few, very limited ways to "win" this game ... well, that's kind of the point. The planet-builder is based on what we know about what it takes to produce life as we know it. And that list of requirements and contradictions really narrows your options. Ultimately, this site should make it clear why finding a "Goldilocks" planet is such a chore, and why everybody is so prone to get excited about the possibility that "life as we know it" isn't the same thing as "life".

Kamis, 30 Desember 2010

It all starts/ends here

Posting the same thing twice is a repeat. Posting it three times is a tradition.

At various points this quarter we'll be talking about the origin of life, the early history of the earth and the importance of asteroid impacts.

For everyone who has ever wondered what it would be like when a 500km diameter asteroid crashes into the earth. If you go to YouTube to watch it you can click a little link to watch it in high def. (highly recommended). You might also want to wait until you can crank up the speakers. The perfect soundtrack to the end of the world. Or the beginning...

Senin, 18 Januari 2010

Panspermia

Panspermia is the idea that life on earth was 'seeded' by the arrival of organisms or compounds from space. Not necessarily little green men with a sinister plan, but maybe primitive microbes that then evolved into all life on earth. An interesting idea that is usually rarely mentioned in biology courses because, for me at least, the more interesting question is could life have once spontaneously arisen on earth? If so, under what conditions and how do these conditions relate to what we know about the early earth?

However if you want to read more about panspermia there are some fanatics on the web (just google it) or you can read this 2005 Scientific American paper - Did Life Come From Another World? for a more balanced view.

Selasa, 05 Januari 2010

Start with a bang

Okay, I'm allowed to have the odd repeat. I think I shall make it a tradition to start this course with a bang.

We didn't actually get onto abiogenesis and the very early history of the earth today (don't worry we'll get to it later). However I don't think I'll let that stop me posting this clip from the Discovery Channel. For everyone who has ever wondered what it would be like when a 500km diameter asteroid crashes into the earth. If you go to YouTube to watch it you can click a little link to watch it in high def. (highly recommended). You might also want to wait until you can crank up the speakers. The perfect soundtrack to the end of the world.

Sabtu, 28 Februari 2009

Controversy Over World’s Oldest Traces Of Life

ScienceDaily (Feb. 28, 2009)
The argument over whether an outcrop of rock in South West Greenland contains the earliest known traces of life on Earth has been reignited, in a study published in the Journal of the Geological Society. The research, led by Martin J. Whitehouse at the Swedish Museum of Natural History, argues that the controversial rocks "cannot host evidence of Earth’s oldest life," reopening the debate over where the oldest traces of life are located.

Jumat, 16 Januari 2009

Life on Mars?

The definitive discovery in Mars’ atmosphere of methane — often, but not always, a compound hinting at life — introduces the possibility of underground organisms.

A paper from yesterdays edition of Science raises some intriguing possibilities that underground 'microbes' may be producing methane on Mars. Or maybe it's just a natural phenomenon:

About 0.6 kilograms of methane emerge each second in the summer, Mumma said, which is comparable to the emissions from a natural oil seep near Santa Barbara, California.

Thirty six years later and we still don't know if there is Life on Mars.

Minggu, 11 Januari 2009

The year of Darwin

If Charles Darwin had had a laptop, he probably would have been a blogger--so eager was his desire to disseminate and discuss his ideas with the world.

I think I already mentioned here somewhere that 2009 will see BOTH the 150th anniversary of the Origin of Species and the 200th anniversary of Darwin's birth. The journal Science has a page that collects together news features, scientific reviews and other special content. There are already some interesting things there and I believe they are planning a monthly series of essays celebrating Darwin so it will be worth checking back later in the year.

Three days ago, the second issue of Science in the year contains a very important paper on abiogenesis, 'Self-Sustained Replication of an RNA Enzyme'. We will talk abou this later in the course but although an RNA 'world' has been postulated as a precursor to our DNA world no-one, to date, has shown that RNA replication could be self propagating (ie RNA acting as the enzyme that can replicate itself without the help of other molecules or cell components). There's a nice writeup of the work at ScienceDaily.

This is pretty big news. NPR had a brief interview with the lead author on All Things Considered today which you can listen to here.

Rabu, 07 Januari 2009

Start the quarter with a bang

We didn't actually get onto abiogenesis and the very early history of the earth yesterday (don't worry we'll get to it later). However I don't think I'll let that stop me posting this clip from the Discovery Channel. For everyone who has ever wondered what it would be like when a 500km diameter asteroid crashes into the earth. If you go to YouTube to watch it you can click a little link to watch it in high def.
 
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