J.C.MacSwell

This guy was the first to make the measurements back in the 17th century:

http://en.wikipedia.org/wiki/Ole_R%C3%B8mer

Aside from being in the habitable zone and having water, what particular evolutionary advantages does the Earth (or the solar system it floats in) have?

 

A few I've found so far:

 

1) The protosphere, the nebulous disk from which the solar system arose, formed of matter from a heavier star which contained a wide variety of heavier materials.

2) The Earth was formed of a mass which contained a wide variety of elements.

3) The Earth was protected from the impact of heavier asteroids by the proximity of the gas giant Jupiter, the vacuum cleaner of the solar system

4) Meanwhile, smaller asteroids and comets, having less gravitational attraction to Jupiter, were let through into the innermost solar system, providing water, organic materials and minerals.

5) By an amazing stroke of fortune, our planet has a stable moon, which is highly exceptional for terrestrial planets. Usually, natural satellites of planets our size either collide with the planet or rapidly drift away from them. By causing oceanic tides, the moon brings many advantages to the Earth's biology and in particular to its evolution. Without it, it may have taken far longer for life to migrate onto coastal areas and later inland, and for all we know it might never have happened had some of the first sea animals not been swept away to the shore.

6) The Earth has a magnetosphere which repels cosmic radiation and solar mass ejections which would otherwise almost fully sterilize the planet.

7) The Earth has an ozone layer which offers a protection against UV rays. However, as ozone is relatively likely to form in an atmosphere rich in oxygen, this is linked to the probability of high atmospheric oxygen.

8) In addition to having water at all, the Earth has actual oceans,

9) The Earth has plate tectonics, which furthers biodiversification compartmentalizing the earth into many separate as well as non-separate areas, thereby allowing the biosphere to experiment with evolution in different environments; adding to the variety of the terrain will add to the variety of the life-forms inhabiting it.

5) is interesting. Large areas of half time land / half time sea (and all other ratios between low and high tide) might certainly help transition from sea to land as well as force bio-diversification.

A change in pitch is a physical change.

Keep in mind that the spring is in all inertial (and other) frames at all times, although it is always at rest in just one.

It is not doing a dance to keep them all happy.

It simply is measured differently in each frame.

It's basically because your body 'feels' the time of your original time zone, meaning you wind up either getting to sleep later or being sleepy very early. Sleeping on the plane would help, but isn't always possible due to cramped seating.

I find it a lot easier flying West a few time zones. Adjusting is like staying up late but getting to sleep in. Coming back East is a much tougher adjustment.

Why is that?

There is friction, and other mechanical efficiency limits, but also the pistons are "running away from" the forces that are powering them. It's much harder to push with force against something that won't resist, and it's the force on the pistons that produce the torque.

How come?

Multi blade props have more "sail area". That sail area can develop more torque than less sail area. When the prop speeds up the blades are interfering with each other, there is not enough energy to go around. 2 and 3 blade props are all that is required to get the maximum energy from the swept area of the prop.

I dont understand. If the length contraction is real and physical some expansion must occur for there to be "no longer any length contraction".

As measured from the Earth, the twin expands in the direction of deceleration until he is at rest in that frame.

The vast majority of solid matter is empty space. If a Hydrogen nucleus was the size of a paperclip and sitting in the centre of an American football stadium, the electron would be outside the stadium.

Couldn't afford a ticket?

It is common in the inverse.

velocity in meters per second

acceleration in meters per second squared or per second per second

jerk (change in acceleration) in meters per second cubed or per second per second per second

Dear swansont,

 

What is then which you expected it to be? How about the solution with length contraction, is it so a sound one?

 

Sincerely,

Nimit

-------------------

http://www.vacuum-mechanics.com .

IMO, if there is an aether, or whatever you want to call it, whatever it is has to allow for length contraction.

The old aether didn't do that.

I see. So why does the torque decrease?

At any given rpm those are the maximums for torque or power.

At higher rpm the engine cannot continue to maintain greater torque. Only reducing the load will allow the engine to achieve higher rpm, so the torque must fall off. The power output continues to rise due to the greater rpm, until that reaches a maximum as well. At highest possible rpm (not shown, it's off the graph) there is no torque or power output at all. (though you could get some instantaneously from the momentum of the engine)

Have a look at this page: http://www.howstuffworks.com/horsepower1.htm

 

Just before the "Torque" infobox, it states: "[...] convert torque to horsepower you simply multiply torque by rpm/5,252."

 

After the infobox, there is a curve rpm/(hp & torque) which clearly doesn't demonstrate a linear relationship.

I am guessing that the torque goes down (as the rpm goes up) due to the fuel mixture not exploding fast enough as the piston already is moving down due to flywheel inertia. Is this correct?

 

If this is so, then the increase in hp as rpm goes up is less efficient that when the torque is high, right?

This is true at any given time, or point on either curve. The power is the torque times the angular velocity.

The graph shows the horsepower the engine is capable of at a given rpm, and separately the torque the engine is under at the given rpm and horsepower, but with no numbers to indicate the actual torque (the scale on the right indicates horsepower only).

yes it seems to be logical answer, and explains it.

It is not necessary (or even a guarantee of stability) for the center of buoyancy of an object to be above that of the center of gravity for it to be in a stable floating position.

Unless you add ballast, which could be water or a weight, the shape is not stable.

The righting arm from the changing center of buoyancy does not change fast enough, even at small angles of "heel", to counteract the "tipping moment" that is created.

http://en.wikipedia.org/wiki/Metacentric_height

There is no reason to believe that we are that rare at this point. If the nearest "somewhat like ours" solar system had some species that had advanced to our level, would they know we exist?

We have a long way to go just to get in the game, to be considered one of the "they" in someone else's "where are they?".

They are often used interchangeably, but also generally used in different contexts.

Say for instance, referring to the motion of a boat at sea vs the movement of a boat at sea. The first would refer to the pattern, and the latter more the displacement.

Polarization in these discussions refers to photons and the orientation of the electric field. Spin is intrinsic angular momentum, and in these discussions is usually describing a massive particle. However, you can have spin polarization — orienting all of the spins of an ensemble in a certain direction.

That would require interaction with something other than the ensemble, correct? (I'm guessing)

Also, what would a typical ensemble consist of? Is this where you meant massive particles?

Moved to pseudoscience.

 

The forces involved are not obeying the strong form of Newton's third law, so of course angular momentum is not conserved.

 

Edit

In addition, you are not considering the angular momentum due to translation.

I think this is where he seems to have trouble.

Well, that's tantalizing. Who would I read if I wanted see some theories on the subject?

Thanks

If you want an entertaining non technical overview I recommend this:

http://en.wikipedia.org/wiki/In_Search_of_Schr%C3%B6dinger%27s_Cat

I believe the Aspect experiment and Bell's theorem taught us that that the disruption of entanglement is fundamentaly non-local, that even if there are hiddin variables, they too are non-local in nature.

That was my impression as well

Correct me if this belongs in a different thread. The question I would like to ask is does any string theory, with it's multidimensial ideas offer any insight concerning those kinds of hidden variables? Is the consideration of an extradimensional cause resulting in instant disentanglement a property of any of the well known string theories.

Good question.

Non - locality really messes with causality and time. I have no idea how string theory might solve that.

Having said that, I can't make sense of it without extra dimensions either.

I suppose you could come up with an experiment where the alive/dead superposition could interfere and have some result that could be measured, but I can't think of one right now. We can only measure alive or dead because those are the eigenstates of the system; once we open the box, we collapse the wave function. But until we've done that, or there has been some other interaction that does it, we have a superposition of states.

 

The purpose behind this thought experiment is to illustrate the weirdness of quantum mechanics.

Here's my attempt from a few years back (2005):

What if you had two cats in the box, one male and one female. After, say, 10 minutes a decay device will trigger one of them dead in a way that won't effect the other. (Say it triggers a cyanide capsule to rupture in the stomach).

 

So you have a live/dead cat and another live/dead cat. Can they interfere with each other?

 

Assume there is enough food and water in the box/system and half the box was isolated/compartmented so the cats can't get to it because of a trap door than wasn't (quite) big enough.

 

After a year the trap door is sealed and the isolation/compartment is saved and the remaining half is jettisoned into a black hole.

 

When the isolation/compartment is opened could it contain any kittens?

 

Can anyone confirm to me that it would be FAR easier to send a rocket into orbit right at the equator? Also, it would be far less easier to get something in orbit spinning the same direction as the Earth as apposed to the opposite direction.

 

 

I can't see why this wouldn't make sense, but I want to make sure i'm correct before I add it to my book of things I know

Yes, but you have the bold part backwards-it would be far easier (not less easier) to get something in orbit spinning the same direction as the Earth as apposed to the opposite direction

 

You're in space! You don't need to maintain it. Don't tell me that you guys actually thought friction would be significant factor in space travel...

 

All you need is enough fuel to speed up and slow down. And maybe a little extra to change direction.

You still have background radiation, from every direction equally in the frame of the cmbr isotropy where all your stars, planets etc. pretty much reside.

While insignificant for short durations at low speed, maintaining significant speeds wrt to that, for long periods of time, requires significant amounts of energy and mass for propulsion.

If you can get to the speed you want, why couldn't you supply sufficient thrust to maintain? The maintenance thrust required is considerably less than that required to reach the desired speed in the first place.

Considerably less but maintained for hundreds of years (for an extremely "local" trip on the scale we are discussing), not just the days or weeks required to get up to (and down to) speed.

Any speedometer, connected with moving vehicle or with moving object, measures the proper velocity.

 

Any speedometer compares the length of passed way and the period of time, spent on this way. Any speedometer uses its proper time. Proper time period is always shorter than corresponding coordinate time period. Proper velocity is always bigger than corresponding coordinate velocity.

 

Imagine a huge man, with the length of one step, equal to one c (299792458 m). If he made 10 steps per one second, measured by his internal brain clock, he will have the proper velocity, equal to 10 c (10*299792458m/s). In order to compute his coordinate velocity, the man must have inherent internal speedometer and another device, - calculator: v_t = v_tau/gamma; gamma=sqrt(1+( v_tau/c)^2); v_tau=10c; v_t=0.995c.

Just to add:

If that is it, "huge man taking steps", then describing his step as 299792458 m means what? I can do that with respect to some frame, take ten 299792458 m steps, measured in a frame that is moving almost c wrt me, in one second of my time, but wrt that frame I am still moving at less than c.

I can easily produce a speedometer that will register 10c. I simply scratch out kph on the display and replace it with "c" and it will accurately measure your description of "proper velocity" in some frame's distance and my time, but unless you recalibrate your speedometer to do this it will never register 10 c.