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Physics A-Level

Finally, a Swimming Pool on Mars

7/25/2018

2 Comments

 
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Well... before we get excited, what is really there? Where is this water? How big is it? What is its composition? What does this say for life of Mars?

Scientists estimate that the body of water is a minimum of 1m deep and likely to be trapped under ice. Interestingly, it is deduced that the lake is composed of a high salt concentration, making it less likely that it will freeze. Highly concentrated brine lakes pose a decreasing likelihood of life "as we know it". That caveat is important, because, in truth, we don't know what life would look like outside of Earth, but its certainly promising news. It seems like liquid water was once present on the surface of Mars, but that is long gone...

Life, on Earth, has been found in extreme heat and chemical conditions (like around deep sea volcanic vents), where water plays a central role in bio-chemical processes important for life. "Extremophile" bacteria have now been found in highly acidic, alkali, hot, cold and more. Another example of wiidely distributed life is tardigrades (although admittedly much bigger and more complicated than simple single cell organisms!) and have been shown to survive cryogenic freezing for decades and even the vacuum of space! Theres no telling what or how life can vary since.... we just don't know what it could look like.

Satellite imaging techniques like these need to be refined and could help find more such bodies of water. Methane lakes, for example, have also been found on Titan, Saturn's largest moon.

Can we go to this lake?! It may be too far under ice for current robot technology and space delivery systems to tackle, although it seems like a real option for future Mars missions since water is the 'holy grail' of the signature of life 'as we know it'.
Do you think there is life outside of Earth? Answer in the comments!

https://www.bbc.com/news/science-environment-44952710
https://en.wikipedia.org/wiki/Lakes_of_Titan


2 Comments

Ants Will Steal Your Cheerios... sort of

7/19/2018

1 Comment

 
Fascinating research from the Weizmann Institute is aiming to understand the cooperative behaviour of ants to deliver food to their nests.

Ants are well known for being able to carry/move much more than their body weight, but how do they know which way they're going? Who's role it is to do what? How do they correct their path? How is all of this information communicated? Can this be modeled somehow for human purposes such as creating a robot ant army or a flying drone army to autonomously deliver packages or rescue people from a wreckage...?
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The research describes how some ants act as 'lifters' and some as 'pullers' to physically move a piece of food (a cheerio!). 'Pullers' align their body parallel to the direction of motion to maximise the force exerted on the cheerio whereas 'lifters' simply lift the cheerio to reduce friction with the surface. As the cheerio moves, each individual ant corrects their body alignment and exerted force.

There are lead ants which regularly prod the collective group in the direction of the nest. They also describe how the roles of different ants can change during carrying, and how that is communicated to the group. There is essentially an 'unspoken' feedback mechanism whereby all corrections are made individually, but externally guided by the leader ants. The feedback sensitivity is such that the cheerios don't spin out of control, or that the cheerio doesn't overshoot its intended destination.

The research paper demonstrates the utility of using statistical physics to explain the motion of multi-component forcing to quite beautifully describe the collective motion of ants...!

https://www.nature.com/articles/s41567-018-0107-y
1 Comment

And Man Said: "Let us make Brains"

7/12/2018

1 Comment

 
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And man said: "Let us make Brains", and they did.

Sergiu Pasca from Stanford University has been working on growing brains from stem cells. Stem cells are the initial cells found in growing embyo's that differentiate to form the structures of every organism. A cell can be differentiated (i.e. initiated for a certain task) using chemical techniques and has now been utilised by Pasca and his colleagues to create a remarkably "realistic" rudimentary brain... a few millimeters in length.

Although, this is a far cry from making bio-cyborg engineered humanoids, the research is promising in that it provides a platform to study and model human brain tissue that is normally hard to come by, for obvious reasons! This has obvious ramification for the development of our understanding of neuro-degenerative diseases and brain disorders.

It will take a while to arrive at a something remotely resembling 'normal' brain function. But the research is a starting point, yet opens a whole Pandora's box of ethical issues that scientists have been grappling with for a while, in the hope that once these experiments become a reality we will be better prepared to deal with the ethics.

https://www.pascalab.org/
https://www.nature.com/articles/nmeth.3415
https://www.nature.com/articles/s41567-018-0200-2


(Brain image is from the article in the second link, Also found in a google image search!)

1 Comment

First Protoplanet Imaged!

7/4/2018

1 Comment

 
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Stunning first images of first protoplanetary disk WITH PLANET!

For decades the mechanism by which planets form around stars was not fully known. In the early stages of planet formation, gas surrounding a central star (typically in a nebula) spirals around that star forming a disk called an 'accretion disk'. Within this accretion disk it is believe that gas (and/or clumps of matter) accumulates to form planets. This accumulation of gas in to a planet would be seen as a gap (or dark ring) at the radius at which that planet is formed.

This is exactly what was reported by scientists working with data from ESO's aptly named "Very Large Telescope" (VLT).... not to be confused with the "Extremely Large Telescope"!

Interestingly enough, this planet is at a distance from its star similar to that of our Sun and Uranus, but its temperature is 1000degrees Celcius (Uranus is ~-215degrees). The scientists were also able to observe features of the atmosphere and composition of the gas giant, named PDS 70b.

Great news for the astrophysics community.

However, one image cannot explain the full picture and the many other possible mechanisms of planet formation. We will need to wait and see until the data is in... lots and lots of data.

https://www.sciencedaily.com/releas…/2018/…/180702094040.htm

1 Comment

    physbot

    Theres something interesting in the ether...

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