Gravity with Brian Cox

Grumpyrocker

Emp_Fab said:

I want to make love with a super-brainy female astro-physicist.  Nothing is sexier than a highly intelligent woman.

vale

ICBM said:

vale said:

on a tangent, that is why thing like the slug thread (also in off topic) makes me feel sad. on that i'm very much with whoever it was there who said they collect snails & take them out to the country to release them, rather than kill (i forget the commenter's name but i gave them a wiz).

on earth slugs are treated by many as a loathsome pest to be got rid of, but on any other planet in our solar system (or according to your inclination, the universe) they would be considered the most sophisticated known life-form. the very kings & queens of all evolution!

there's tragic perspective for you.

In fact in cosmic terms it isn't very long since that would have been true on Earth. So if there is other intelligent life and they are capable of getting themselves here, perhaps they will think of us as slugs... in which case it would actually be better to be alone.

“Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” - Arthur C. Clarke

extremophiles are a really fascinating start point for thinking about what form life on other planets might take. can recommend these clips if you are curious about that scene.

prof hazel barton (extremophile specialist involved with nasa seti etc) talking about how micro-organisms can litereally swim through rock, co-ordinate themselves in mutually supporting symbiotic relationships, travel around in vapour hazes.

just add to that the hive consciousness that we see on earth in ants & bees, a community acting as one multi-bodied organism, & it's not hard to see how life could exist for billions of years elsewhere in the universe (or even our solar system) without ever touching the surface of a planet. really fascinating. makes a brain buzz.

short clip


full lecture

Axe_meister

Here's one for you (I've never heard a believable explaination).
A ferri magnetic object is travelling at a constant speed and come into contact with a magnetic field. It's trajectory is altered so in effect a force is applied. Yet apparently no work is done.
The same applies to gravity. In addition you can use gravity to sling shot objects, yet there is no energy transfer between the objects. 

ICBM

Axe_meister said:

Here's one for you (I've never heard a believable explaination).
A ferri magnetic object is travelling at a constant speed and come into contact with a magnetic field. It's trajectory is altered so in effect a force is applied. Yet apparently no work is done.
The same applies to gravity. In addition you can use gravity to sling shot objects, yet there is no energy transfer between the objects. 

Yes there is.

The energy gained by a spacecraft using a planet as a slingshot is lost by the planet - from the potential energy of its orbit around the Sun... ie as the spacecraft is accelerated, the planet slows down and moves closer to the Sun. Given the relative masses, it’s immeasurably small for the planet, but it does occur.