If there are aliens, what will they look like?

[CalG]

Have they found intelligent life on EARTH yet?

 

[RoyJackson]

Have they found intelligent life on EARTH yet?

Well, TBN is here...
Not sure about the rest...

 

[MossRoad]

Yes, I do...
This universe is too big to think life, in some form...and, IMHO, intelligent life, could not have evolved.
Although I think FTL speed can be attained, that doesn't mean extraterrestrial has visited us...a possibility, certainly, but not a fact.
So, the answer in this case is faith, not fact...since I cannot prove it...
But, life on this small green planet most certainly gives credence to life on other planets

I believe I'll have a beer tonight!

 

[tradosaurus]

Yes, I do...
This universe is too big to think life, in some form...and, IMHO, intelligent life, could not have evolved.
Although I think FTL speed can be attained, that doesn't mean extraterrestrial has visited us...a possibility, certainly, but not a fact.
So, the answer in this case is faith, not fact...since I cannot prove it...
But, life on this small green planet most certainly gives credence to life on other planets

Thank you for being honest. That was my point in this thread. Believing in aliens takes a leap of faith which is akin to believing in something that you can't prove, like moon landings, gravity, spherical earth. People have shown grainy pictures of flying saucers and even supposed alien beings. Some people have claimed to have been abducted but my belief is that they are nothing more than demons (sulphur smell, Alester Crowley version).

 

[tradosaurus]

With my BMSE degree in Mechanical Engineering, professional license, and 40 years of engineering experience, I am always amazed at how some people ever got their engineering degree. I do remember being told once that being able to make it through engineering school and having basic common sense are not always compatible. I have seen that in practice, and have seen it again while following this thread.

Congrats on the difficult degree and experience. I've met experienced engineers with PE licenses that at times make me wonder how they attained their license. Being able to regurgitate numbers and formulas doesn't guarantee one will have eyes to see the truth around them.
There are so many observations and conflictions of what we learned that should make you question some of the aspects of modern science.
1) Water always seeks it's level without a container. Always.
2) Vacuum can't exist next to a pressure system without a barrier. Ever.
3) Long distance shooting (battleships, snipers) do not take into consideration the supposed rotation of the earth.
4) Rockets can't operate in a vacuum. A simple force diagram shows the rocket as a complete system which means the exhaust has to push off of something (water, air, land). (Newtons 3rd law
of motion)
5) Everything ultimately falls apart and disintegrates over time (2nd law of thermodynamics) which proves evolution is false.
6) If the earth is a sphere we should not be able to see buildings, boats at a certain distance as they would be behind the curve. (see Lake Michigan to Chicago skyline).

 

[/pine]

Thank you for being honest. That was my point in this thread. Believing in aliens takes a leap of faith which is akin to believing in something that you can't prove, like moon landings, gravity, spherical earth. People have shown grainy pictures of flying saucers and even supposed alien beings. Some people have claimed to have been abducted but my belief is that they are nothing more than demons (sulphur smell, Alester Crowley version).

LoL...You really should be posting your tripe in the 'Groan' thread...it would be much more fitting...

Methinks you are really just trolling and stirring the pot...nobody and I mean nobody (of adult age) could possibly be so ignorant of tangible proof...denial is not just a river in Africa...!

 

[bcp]

3) Long distance shooting (battleships, snipers) do not take into consideration the supposed rotation of the earth.

Long Range Shooting: External Ballistics - The Coriolis Effect

Master long-range shooting by understanding the Coriolis effect. Our expert guide explains how to adjust for optimal accuracy.

thearmsguide.com

From:

Ballistics

In the northern hemisphere, the trajectory will be deflected to the right. A projectile traveling 1000 m/s due north at latitude 30o N would be accelerated to the right at 0.07 m/s2. For a 30 second time-of-flight, corresponding to about 30 km total distance traveled, the projectile would be deflected by about 60 m. So for long range artillery, the Coriolis correction is quite important. On the other hand, for bullets and water going down the drain, it is insignificant!

Bruce

 

[2LaneCruzer]

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QUESTION #221

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If space is a vacuum, then how do space capsule's retrorockets steer?​

Asked by: Mr. Wood

Answer​

The fact that space is a vacuum nicely isolates this problem as a demonstration of Newton's third Law, commonly phrased as 'every action has an equal and opposite reaction.'

It is not necessary for the rocket exhaust to push against anything EXCEPT THE SHIP ITSELF. You see, when the combustion of fuel takes place inside the rocket (think of a long vertical cylinder with the 'bottom' open) the exhaust gasses produced expand quickly in all directions. The molecules slam into anything in their path exerting a small force each. Thus some molecules push against the 'right' side and some push against the 'left' side, and all these sideways forces cancel each other out. Some molecules slam against the 'top' of the cylinder, but since there is no bottom of the cylinder, there is no force to cancel this out! Therefore the net force will be in the 'up' direction.

Another way to think about the situation is as a conservation of momentum problem. Any isolated system will conserve total momentum. Thus if you imagine a stationary ship, plus the fuel and oxygen molecules on the ship, p=0. If a few trillion atoms of exhaust are shot in one direction into the vacuum of space, the rest of the ship must move in the OPPOSITE direction with the same momentum (mass x velocity)

You can simulate this situation by throwing some bean bags (or bowling balls, or any other objects you have lying around) in one direction as you sit in a chair with wheels or stand on roller blades or ice skates. Whatever direction you push on the object, the object will push back on your hand with the same force, but in the opposite direction. Therefore you and the object you throw will move in opposite directions.
Answered by: Rob Landolfi, Science Teacher, Washington, DC

Retro-rockets are usually used to decelerate, not steer, a spacecraft. They operate like any rocket engine in the vacuum of space, by propelling gases in one direction to create an opposite and equal force on the craft. There is no need for air for those gases to 'push against' thanks to Newton's third law of motion.

'Steering' a spacecraft means changing its existing orbit or trajectory. That is usually done by using small attitude control rockets to point the vehicles main, larger rocket engine opposite to the direction you want to head. The main rocket engine is then fired to alter the vehicles original path. That same main rocket engine can be used as a retro-rocket by using the small control rockets to point it in the direction of motion before firing it.
Answered by: Paul Walorski, B.A., Part-time Physics Instructor

 

[CalG]

Congrats on the difficult degree and experience. I've met experienced engineers with PE licenses that at times make me wonder how they attained their license. Being able to regurgitate numbers and formulas doesn't guarantee one will have eyes to see the truth around them.
There are so many observations and conflictions of what we learned that should make you question some of the aspects of modern science.
1) Water always seeks it's level without a container. Always.
2) Vacuum can't exist next to a pressure system without a barrier. Ever.
3) Long distance shooting (battleships, snipers) do not take into consideration the supposed rotation of the earth.
4) Rockets can't operate in a vacuum. A simple force diagram shows the rocket as a complete system which means the exhaust has to push off of something (water, air, land). (Newtons 3rd law
of motion)
5) Everything ultimately falls apart and disintegrates over time (2nd law of thermodynamics) which proves evolution is false.
6) If the earth is a sphere we should not be able to see buildings, boats at a certain distance as they would be behind the curve. (see Lake Michigan to Chicago skyline).

there are several mis-statements in that list.

Vacuum, being only a "Pressure", less than "normal". It IS the force that moves the wind. AND it occurs ALL THE TIME.
Even "deep space" has many molecules per m^3 in it's volume.

One could go on, but that would not alter tha most subtle detail of any alien's appearance.

 

[the old grind]

To say that rockets need something to 'push against' is to ignore that the pressure inside a rocket motor pushes everywhere but where the exhaust comes out. Propulsion is derived because expanding gases don't go out both ends. 8th grade science class.

Nobody ever said that our atmosphere and the vacuum of space are 'next to each other'. Rather there is a transitional zone between the two, gases being held to planets by gravity if/when close enough to them. Density & atmospheric pressure are inversely proportional to altitude and the 'zone' is many times as 'thick' as what propellers 'push against'.

Sorry for using big words.