If so called gravity is weaker...

Quote from: sceptimatic on December 28, 2013, 03:47:31 PM

Ok, so let's get this straight. If and I mean IF I could float up into the sky at 1 mph, I can float straight through the atmosphere into space at 1 mph. Is this what you are saying?

Yes. If you can maintain any speed, it will get you there eventually.

Quote from: sceptimatic on December 28, 2013, 03:47:31 PM

Also, if you believe that story about the vent cover then you need treatment.

I did say "believed by some", not "I believe".

So, setting aside your own beliefs for just a moment, and speaking in terms of RE science, do you understand the concept of escape velocity, and why it is not required for general space flight?

Yes, ok, I accept what you are saying. I obviously don't believe in space travel or escape velocity or gravity, but I accept what you are saying in terms of, I can't counteract it with any reasonable answer, other than to say, well space does not exist and all that stuff, which I'm not going to do, so fair enough.

And which ballistic object do you know that's escaped the atmosphere?
Do you people actually have this stuff IMPLANTED into your minds from birth from a chip or something?
Surely you can't read up on it and just accept it all, there must be drugs involved in some fashion, or like I said, some kind of micro chip implanted into your skull that interferes with your brains ability to use rational thought.

I CAN'T STOP LAUGHING!!!!!!!!  HILARIOUS!
All this rocket crap makes sense to these guys because they are naïve believers.  Astrophysicists can make it all up because the rockets don't REALLY leave our atmosphere.

Quote from: Levi Dettwyler on December 27, 2013, 02:46:40 PM

Please just take an introductory physics class at a local community college.  The fact that you asked this question in the first place means you cannot possibly understand the answer until you have the sufficient mathematical background.

Unless you think math is part of the conspiracy too, in which case, just forget it.

Go and take a long walk off a short pier you waste of space.

I wasn't kidding.  The actual answer to your question involves some basic calculus and an understanding of the relationship between position, velocity, and acceleration.  Do you even know what escape velocity is?

Quote from: sceptimatic on December 28, 2013, 10:00:18 AM

And which ballistic object do you know that's escaped the atmosphere?
Do you people actually have this stuff IMPLANTED into your minds from birth from a chip or something?
Surely you can't read up on it and just accept it all, there must be drugs involved in some fashion, or like I said, some kind of micro chip implanted into your skull that interferes with your brains ability to use rational thought.

I CAN'T STOP LAUGHING!!!!!!!!  HILARIOUS!
All this rocket crap makes sense to these guys because they are naïve believers.  Astrophysicists can make it all up because the rockets don't REALLY leave our atmosphere.

Listen, Earthy, Baby, Scepti's Sockpuppet. Just because we disagree with you and Sceptic doesn't make us naive. It makes us people who disagree with you. Many of us understand the physical principles involved. You don't, which is why you you attempt to insult and belittle us. It props up your fragile ego and acts a smokescreen for your complete lack of understanding of anything we are talking about.

Also, if you believe that story about the vent cover then you need treatment.

"Operation Plumb-bob" was carried out at the US Nevada testing site from May to October of 1957.  During the Pascal-B nuclear test, a 900-kilogram (2,000 lb) steel armour-plate cover was blasted off the top of a test shaft at a speed of more than 66 kilometres/second. Before the test, experimental designer Dr Robert R Brownlee had performed a highly approximate calculation that suggested that the nuclear explosion, combined with the specific design of the shaft, would accelerate the plate to six times escape velocity.

After the event, Brownlee described the best estimate of the cover's speed from the photographic evidence as "going like a bat out of hell!"

Quote from: sceptimatic on December 28, 2013, 03:47:31 PM

Also, if you believe that story about the vent cover then you need treatment.

"Operation Plumb-bob" was carried out at the US Nevada testing site from May to October of 1957.  During the Pascal-B nuclear test, a 900-kilogram (2,000 lb) steel armour-plate cover was blasted off the top of a test shaft at a speed of more than 66 kilometres/second. Before the test, experimental designer Dr Robert R Brownlee had performed a highly approximate calculation that suggested that the nuclear explosion, combined with the specific design of the shaft, would accelerate the plate to six times escape velocity.

After the event, Brownlee described the best estimate of the cover's speed from the photographic evidence as "going like a bat out of hell!"

I've got some old Enid Blyton famous five books from when I was in the infant school. I think they are in the attic under my grandma's rocking chair that her clothed, skeleton remains sit in. I'll ask a psycho, I mean psychic to get in touch with her soul and ask if you can borrow them. It's pretty good fictional reading, about a bunch of detective kids and their dog.

A 2000lb plate blasted off the top of a test shaft, hahahahaha.
"Boss, boss, don't fire, don't fire"...BANG! "damn it boss, we forgot to unbolt the 2000lb plate from the test shaft and now look, it's blasted into 6 times escape velocity, because we saw it and timed it and all that stuff, you know."

Go and get some fresh air and get yourself a reality check you dummy.

sceptimatic and everybody else, please watch the personal attacks in the upper fora.  Thanks. 

Go and get some fresh air and get yourself a reality check you dummy.

I was attempting to address your question about ballistic missiles.  The point is that with ballistics, the body's velocity relies solely on an initial propulsive force—as per a cannonball for example.  The cannonball's velocity gradually decreases over time, and it returns to earth (if it doesn't strike its target first).

A rocket on the other hand (obviously) has its own inbuilt source of propulsion, which is why—theoretically—it could escape earth's gravity field with only a relatively slow velocity of say 500mph.  The rocket's high velocity is not to escape earth's gravity per se, but to save on its fuel loading.

The steel shaft cover is an example showing that it IS possible for a ballistic missile to escape earth's gravity field.

If so called gravity is weaker the higher you go, then why do so called space craft need to reach an escape velocity to get into so called space?

Sorry - but the premise of the question is incorrect - escape velocity is not required to get into space - it is required for an object to maintain an orbit around Earth and not require extra fuel.
Objects like the International Space Station and Communication satellites are propelled into orbits set distances and due to weak atmospheric drag(there is no hard line to the end of the atmosphere and the beginning of space) it will very slowly, lose velocity and being falling to Earth.

A thought experiment: Hold out your hand parallel to the Earth(say at 5 ft) with a bullet in your hand, now drop the bullet. It accelerates towards the earth at 32f/s/s.

Now if you fire a gun with the same bullet from the same height(5ft) as your first drop, parallel to the surface of the Earth - it will take the same amount of time for the bullet to hit the ground as it would if you just dropped it - remember there is no force pulling the bullet up even when fired from the gun.

Now the next experiment requires a lot more force. The bullet in the second experiment wasn't fast enough to escape falling back to Earth - but say this time, our bullet reaches 11.2km/s - by the time gravity has had enough time to accelerate the bullet 5ft towards the earth(remember it was fired at the same height of 5 ft) the Earth's surface has fallen further away (relative to the bullets perspective)

Ignoring atmospheric resistance and obstacles getting in the path of the bullet - gravity will never be able to pull the bullet down fast enough for it to hit the earth. The bullet has just achieved orbit of the Earth.

Again - escape velocity is not required for something to enter space. But it is the best way to put something into orbit around the Earth.

Actually termanader, you're confusing orbital velocity with escape velocity. I recommend looking the two of them up and noting the differences. Nice description though.

Actually termanader, you're confusing orbital velocity with escape velocity. I recommend looking the two of them up and noting the differences. Nice description though.

I am not - please check your references.

In physics, escape velocity is the speed at which the kinetic energy plus the gravitational potential energy of an object is zero.[nb 1] It is the speed needed to "break free" from the gravitational attraction of a massive body, without further propulsion.
http://en.wikipedia.org/wiki/Escape_velocity

"The orbital speed of a body, generally a planet, a natural satellite, an artificial satellite, or a multiple star, is the speed at which it orbits around the barycenter of a system, usually around a more massive body. It can be used to refer to either the mean orbital speed, i.e. the average speed as it completes an orbit, or the speed at a particular point in its orbit.
The orbital speed at any position in the orbit can be computed from the distance to the central body at that position, and the specific orbital energy, which is independent of position: the kinetic energy is the total energy minus the potential energy."
http://en.wikipedia.org/wiki/Orbital_speed

I understand it can be confusing - but a free-falling object in orbit around a body requires escape velocity if no further propulsion is added.

Orbital velocity is a generic term for the speed of an object orbiting another.
Escape velocity is the bare minimum velocity required to maintain a free-falling orbit.

I really don't want to start an argument, but...

From http://en.wikipedia.org/wiki/Escape_velocity, a little further down from your extract:
"Defined a little more formally, "escape velocity" is the initial speed required to go from an initial point in a gravitational potential field to infinity with a residual velocity of zero, with all speeds and velocities measured with respect to the field."

and a little further down the same page:
"If an object attains escape velocity, but is not directed straight away from the planet, then it will follow a curved path. Although this path does not form a closed shape, it is still considered an orbit."
So, while an object at escape velocity can perform something referred to as an orbit, it's not an orbit in the same sense as a satellite.

Furthermore, from the same page again:
"The escape velocity at a given height is √2 times the speed in a circular orbit at the same height"

So, similar but not the same.