21

Physiology & Medicine / Re: Where to start with low cholesterol diet?

« on: 28/10/2013 03:19:00 »

I watched a recent show we have in Australia called Catalyst which contemplated the fact that data linking cholesterol with heart disease could be quite unreliable.

I would love to know what the good Dr. Chris thinks about this, and are there any recent peer-reviewed studies looking into the effects of cholesterol on the heart?

22

Physics, Astronomy & Cosmology / do supermassive black holes exist anywhere other than at the centre of a galaxy?

« on: 28/10/2013 02:28:00 »

Is it possible that one might form in a spiral arm for instance? or that a galaxy might have a multitude of "super-massive" black holes?

And while we're talking about it, is there even a scientific description of what one is?

23

Plant Sciences, Zoology & Evolution / How do birds pick up multiple bugs at a time in their beak?

« on: 22/10/2013 02:57:46 »

I was gardening the other day and had a peewee wandering around collecting various small grubs and ants, then flying off.
I noticed it was able to hold several things in it's beak, but then it would peck down and come back up with yet another grub, without dropping the rest.

Does anyone know how they do this? are they just really quick?

24

New Theories / Re: Gravity Waves: do they exist?

« on: 24/09/2013 07:36:35 »

Obviously the weight of the atmosphere on earth holds everything down.

What gives the atmosphere "weight" if gravity doesn't exist?

25

Just Chat! / Re: Punning is hard(ly) work! Groaning aloud here?

« on: 24/09/2013 05:26:23 »

When reserving your seat on an indian carpet with all your friends, always call centre, so as not to upset the equilibrahma.

26

New Theories / Re: thrust does not work in space

« on: 24/09/2013 05:21:36 »

Gas does no work in a vacuum. It is only a passive participant and not an active force in space. We cannot use it as the basis for space travel. Bottling up gas and shooting it out of a tiny nozzle won't change its basic physical properties inside a vacuum, won't suddenly invalidate the laws of thermodynamics.

The theory of space travel based on gas jets and/or liquid propellants is a science fiction from the 1800's (Jules Verne et. al.) similar to the philosopher's stone and other magical, mystical pursuits we now look down upon. There is also the matter of the faked/fraudulent results of rocket pioneers such as Goddard which I will get to later.

If you ask why this is hoax is still going on it is because science has become a religion and NASA it's church. Specifically space travel is one of the Holiest of Holies. Try debunking a religion/cult and see how far you get. Once someone has been indoctrinated, invested themselves in its beliefs, it is nearly impossible for them to divest. For years I believed that space travel was the pinnacle of man's achievement. Now I have to wonder if any rocket has ever been past as far as we can throw it up from the ground.

I realise I'm trying to enlighten a dead horse here but surely the gas itself is of little importance in the thrust of a spaceship. It is the explosion inside the ship (and therefore not even in a vacuum if it matters - which it doesn't) which drives the gas out through the jet on one side of the ship, but doesn't drive the gas out of any other wall in the engine and therefore the ship has no choice but to move in the direction that the gas is not leaking out of. This was the beautiful cube example from earlier.

You can't see that you've indoctrinated yourself to believe this fallacy about thrust in space blindly, without analysing the evidence around you and providing alternate theorys to explain the observations.

27

Just Chat! / Re: Punning is hard(ly) work! Groaning aloud here?

« on: 18/09/2013 13:38:41 »

I also like to have tea, scones on the side please.

28

Just Chat! / Re: Punning is hard(ly) work! Groaning aloud here?

« on: 18/09/2013 13:36:14 »

This, on the other hand, is a keys tone.

F flat? Really?

Could be a bass clef - A flat?

I think ice creams that have all the ice cream at the top and nothing in the cone are a tease cone. You eat them with a spooner.

29

New Theories / Re: thrust does not work in space

« on: 16/09/2013 23:11:28 »

I hope you're not on his side and believe that rocket's need air to push on? That's quite wrong. It makes no sense for the gases to know that they're going to push on air before they leave the combustion chamber and not reflect off of the interior walls and thus exchange the momentum of the gas with the momentum of the walls of the chamber? truthseeker67 is unable to grasp science or engineering, I hope you don't think the same way? It looks like you're joking but I wanted to make sure.

Yes. Sorry Pete, I am joking. Also, whoever used the example of the cube with the missing side, i LOVE that example. It explained it beautifully.

I was reading back to the initial argument that thrust is based on "weight". It's a bit like me saying that "I reckon time is based on unicorns, and therefore I have just proved it doesn't exist - can YOU see any unicorns?"

It sounds like something out of a Douglas Adams novel where as soon as something enters weightlessness, it ceases to exist.

30

New Theories / Re: thrust does not work in space

« on: 16/09/2013 07:15:53 »

Call me a sicko, but man I find these threads entertaining!

By the way buddies Airplanes use less fuel at high altitude than they use at low altitude, because the air is thinner at high altitudes and therefore produces less air resistance to slow the airplane down thought i would explain that using my useless physics, so airplanes are more efficient at higher altitudes.

If there's less air and therefore it is closer to being a vacuum, wouldn't the jets start to fail? After all, "thrust does not work in space". []
I like the way that rockets need something to push against and therefore wont work in a vacuum, but when you push a large metal construction against something as solid and tangible as, oh, I don't know... air!, you can break the sound barrier several times over!
I guess, truthseeker, that if you admitted to the truth, you'd have to change your username.

31

Chemistry / Can a fire be scaled down to Smurf size?

« on: 19/08/2013 03:29:28 »

I've wondered this ever since watching the smurfs as a child. If a smurf gathered together a bunch of smurf-sized twigs and sticks and scrunched up a bunch of smurf-sized newspapers which they lit with a smurf-sized match...

How big would the flames be? Because if I tried to light a 'campfire' that small it would just burn up in no time.

32

Physics, Astronomy & Cosmology / Re: Why do mirrors reverse but not invert things?

« on: 06/08/2013 05:26:28 »

If it is a flat mirror, the paths of light will simply reflect without crossing paths. For true inversion/reversal you would need a parbolic mirror (like in a telescope) which would invert both vertical and horizontal.

I guess you could play around and parabolise (if that's not a word, it should be!) the mirror horizontally and not vertically, then you would see yourself as others see you and it would be very disconcerting.

33

Physics, Astronomy & Cosmology / Re: How fast does gravity propagate?

« on: 06/08/2013 05:16:14 »

Having more thoughts - if the problem was shrunk down and it was the Earth that disappeared, I guess the moon would still orbit the sun, however a stable orbit may never quite be acheived. (?)

Sorry, I think I've just clogged this thread with two highly unscientific opinions. []

34

Physics, Astronomy & Cosmology / Re: How fast does gravity propagate?

« on: 06/08/2013 04:29:16 »

I think it would take some time for the Earth to revert to a purely galaxy-centered orbit. We're going pretty fast around the sun and we'd continue to move in whatever direction the sun left us in regardless of what a stable galaxy-centered orbit would be.

I'd also imagine that nearby encounters would have more impact on our trajectory than the centre of the galaxy. I could be wrong.

Having said all that of course, we are in a galaxy-centered orbit at the moment. The same way the moon is going around the sun.

35

Just Chat! / Re: Punning is hard(ly) work! Groaning aloud here?

« on: 01/08/2013 04:45:33 »

I knew a man who was good at smelling, but he had nose sense.

36

Physics, Astronomy & Cosmology / Re: Does the effect of gravity bend with warped spacetime?

« on: 01/08/2013 03:18:24 »

So. If we see the light from a star during an eclipse that is actually behind the sun, but appears to the side, do we feel the effects of gravity as if it was behind or do we feel the effects of gravity from where it appears.

Okay. Now I see what you're asking.

The answer is that we feel the effects of gravity from where it appears, i.e. at the sun itself. That is to say that the source of gravity is the sun and the sun generates a gravitional field and curves spacetime and its that which is bending the light.

Okay, different spin on the question; if the above situation referred to by bizerl exists and a further source of gravity waves is introduced so that those waves encounter the bit of space bent by the existing gravity source, what will those gravity waves do? Are they bent by the gravity source, or do they continue in a straight line?

Thank you Pete for giving your attention to this thread and your in-depth responses, and thank you Chris for crystallising so succinctly what I thought I was orginally asking.

My thought was that if the gravity waves moved in a straight line through the gravity source while the light was made to curve around the gravity source, they could possibly reach a certain destination before the light.

Then I remembered about relativity and how usually everything gets warped out of shape to make sure that this kind of thing doesn't occur.

It also makes me question by what mechanism "gravity waves" or "gravitons" can be directional. How is the information transmitted that the particular wave should pull an object in a particular direction?

37

Physics, Astronomy & Cosmology / Re: Does the effect of gravity bend with warped spacetime?

« on: 29/07/2013 07:17:09 »

bizerl - hopefully pete will drop by and post on this question, it is right up his street.

Sorry but the way it's described is far too confusing for me to follow.

I'm so disappointed because I know if you understood my word salad, Pete, you'd be able to answer easily. I'm sure I'm just missing something fundamental in the way gravitational lensing works.

I'll have one more crack at trying to describe what the mush in my head is thinking...

When light travels through space, it travels in a "straight line" unless spacetime is warped by mass, in which case a "straight line" becomes curved. I'm wondering whether gravity works the same way? If we represent gravity as a whole bunch of threads connecting say, the moon and the Earth, can those threads be curved by distortions in spacetime, the same way light is curved?

Am I over-simplyfying gravity?

Hoping you're still out there Pete...

38

Just Chat! / Re: Punning is hard(ly) work! Groaning aloud here?

« on: 29/07/2013 04:22:54 »

My GP told my wife and I about a new hayfever trial. I told him "Sign us up!"

39

Physics, Astronomy & Cosmology / Re: Does the effect of gravity bend with warped spacetime?

« on: 17/07/2013 05:38:17 »

I wish I could get the image editor to work so I could draw it for you!

If we take an extreme example - the sun's gravity influences us from the direction we see it in. This is because even though by the time we see it, it has been moving for 9 minutes, the photons and (gravity waves? - not sure of correct term) left at the same time and reached us at the same time. so at noon, the sun's gravity is pulling us straight up (ish) and at sunset, the sun's gravity pulls us towards the horizon (again, ish).

If we stick a black hole between us and the sun, such that the black hole's gravitational influence bends the light extremly, lets say 90 degrees, than in this over-simplified thought experiment, we might see the sun setting at noon, even though we know that it's actually overhead(ish). So when the light path is bent, is the gravity path bent as well? Are we pulled to the horizon (the direction we can see the sun) or straight up (the direction we know the sun actually is - or was 9 minutes previously)?

Always happy to confuse the situation further!

40

Physics, Astronomy & Cosmology / Does the effect of gravity bend with warped spacetime?

« on: 16/07/2013 06:02:38 »

I was thinking about gravitational lensing and the ability for a large mass (or technically any mass i guess) to bend the light and make an object seem to be from a different direction. I know that the effects of gravity propogate at the speed of light - ie. the gravitational we feel from the sun corresponds to the position we see rather than where it has travelled since the light left.

So. If we see the light from a star during an eclipse that is actually behind the sun, but appears to the side, do we feel the effects of gravity as if it was behind or do we feel the effects of gravity from where it appears.

I realise that for this example, the effects of gravity of a distant star are next to nothing, but does the concept hold? If so, and the gravity propogates in direct lines when light is bent, does that mean that we could possible feel the gravitational effects of some far off thing before the light reaches it?

And more importantly, can we exploit this fact for some sort of faster-than-light communication?