[Science] NASA confirm: Water ice found on Mars

[poprock]

Originally Posted by LesMTS

But most agree on a broad range of criteria including things like ability to respond to stimuli, ability to replicate independently (unlike viruses) etc etc. I can't remember them all, I think there are seven major criteria. I'll look them up.

Reproduction (rather than replication)
Being multi-celled
Regulation of internal temperature (whether using external heat sources or not)
Metabolism (eating and shitting)
Adapting over time
Growth
Response to external stimuli

I think that’s it, but I always get confused as to why growth isn’t just part of the ‘adaptation over time’ requirement.

[LesMTS]

Originally Posted by poprock

Reproduction (rather than replication)
Being multi-celled
Regulation of internal temperature (whether using external heat sources or not)
Metabolism (eating and shitting)
Adapting over time
Growth
Response to external stimuli

I think that’s it, but I always get confused as to why growth isn’t just part of the ‘adaptation over time’ requirement.

Growth is just an organism growing. Adaptation over time refers to evolutionary processes.

Also, being multi celled isn't a criterion for life. Bacteria, amoebae, etc are all uncontroversially living things.

Here are the criteria (from wiki):
1. Homeostasis: Regulation of the internal environment to maintain a constant state; for example, sweating to reduce temperature.
2. Organization: Being composed of one or more cells, which are the basic units of life.
3. Metabolism: Consumption of energy by converting nonliving material into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.
4. Growth: Maintenance of a higher rate of synthesis than catalysis. A growing organism increases in size in all of its parts, rather than simply accumulating matter. The particular species begins to multiply and expand as the evolution continues to flourish.
5. Adaptation: The ability to change over a period of time in response to the environment. This ability is fundamental to the process of evolution and is determined by the organism's heredity as well as the composition of metabolized substances, and external factors present.
6. Response to stimuli: A response can take many forms, from the contraction of a unicellular organism when touched to complex reactions involving all the senses of higher animals. A response is often expressed by motion, for example, the leaves of a plant turning toward the sun or an animal chasing its prey.
7. Reproduction: The ability to produce new organisms. Reproduction can be the division of one cell to form two new cells. Usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from at least two differing parent organisms), although strictly speaking it also describes the production of new cells in the process of growth.

Viruses fail 1, arguably 2, 3, 4 and arguably 6.

[poprock]

Originally Posted by LesMTS

… being multi celled isn't a criterion for life.

But:

Originally Posted by LesMTS

2. Organization: Being composed of one or more cells …

So, whilst I understand your argument about ameoba etc, I ain’t sure.

[LesMTS]

Originally Posted by poprock

But:



So, whilst I understand your argument about ameoba etc, I ain’t sure.

The criterion is one or more cells.
Amoebae are single celled.

[poprock]

D’oh. Misread of the day.

Now I get you. Cheers. Pass the dunce’s cap, aye?

[Stew]

Well I'll be damned, there's water on Mars.

http://www.guardian.co.uk/science/20...aceexploration

Originally Posted by The Guardian

Nasa scientists last night confirmed that there is water on Mars. The space agency's Phoenix lander has identified ice in a soil sample analysed by its on-board laboratory.

Previous orbiting missions had beamed data such as the view of the planet's surface, above. Others indicated there was ice on the red planet - but Phoenix's discovery is the first direct evidence. "I can now say I'm the first mission to Mars to touch and then taste the water," came the message from Phoenix's Twitter feed yesterday.

Nasa has extended the mission until September 30, adding five weeks to the scheduled 90 days of operations on the surface.

"Phoenix is healthy and the projections for solar power look good, so we want to take full advantage of having this resource in one of the most interesting locations on Mars," said Michael Meyer, chief scientist for the Mars exploration programme at Nasa HQ in Washington.

The soil sample was scraped out of the roughly five-centimetre deep "Snow White" trench on Wednesday. Two previous attempts to deliver fresh material to the lander's on-board oven failed when the soil became stuck in the scoop. This time the scientists exposed most of the material in the sample to the air for two days, so some water vapourised, thus making the soil easier to handle. The find fulfils one of the Phoenix lander's two main objectives - to "study the history of water in the Martian arctic". The other is to study the potential for life in the ice-soil boundary.

In 2006, Nasa scientists, using images from the orbiter, Mars Global Surveyor, found evidence of water flowing fleetingly on the surface. They compared images of the side of a crater taken in 2001 and 2005. The second showed gullies apparently caused by water bursting out of the crater wall.

[Danger]

There's oxygen on Mars too, Cohagan knows about it but the bastard just won't turn it on.