Does a spaceship float or fly?
Discussion
Munter said:
Yes but if they pop into existence stationary, 4.5 million light years apart, and the effect of gravity spreads at the speed of light. It would be 4.5 million years before they start to accelerate towards each other?
The time it takes to collide being another thing I guess could be worked out. But wasn't what I was thinking of.
Sorry, misread your question.The time it takes to collide being another thing I guess could be worked out. But wasn't what I was thinking of.
Always thought it was relative to where it is. For example, Apollo was an orbit around the Earth that happened to coincide with the Moon. The orbit is falling over but not hitting the ground and when it got to the moon they had to fall around it a lot whilst not hitting it. That requires thrust from a rocket to change your delta V when required (??? leap in here, guessing a bit). Pointing it the right way to do that uses the smaller thrusters.
What are the effects between planets, but still falling around the sun? And outside the effect of the Suns gravity?
Edit. I have a degree in bull..... this is how I understand it anyway. I am probably talking cobblers.
What are the effects between planets, but still falling around the sun? And outside the effect of the Suns gravity?
Edit. I have a degree in bull..... this is how I understand it anyway. I am probably talking cobblers.
A spacecraft in "coasting free flight" is travelling on a trajectory imparted upon it by some means of thrust – usually a rocket engine. Whether it is deemed to be "falling" or not really depends on where it is heading and what it is doing.
An Apollo spacecraft on the way to the moon was initially given enough velocity to enter earth orbit - where it "fell" around the earth at 17,500 mph. It was then given an extra boost to increase its velocity to 25,000 mph relative to the earth where it entered a trajectory away from the earth and towards the moon.
Technically, it was now in solar orbit but on a path that would intercept the moon's orbit. The moon's gravity would then cause it to loop around the moon and head back directly towards earth again. However, as it was looping around the moon, the Service Module engine was fired in a retrograde direction to slow the spacecraft to a speed where it would enter lunar orbit. It was now "falling" around the moon.
The Voyager space probes were given initial velocities of over 37,000 mph relative to the sun so that even the sun's gravity could not pull them back. There are therefore in a coasting free-flight out of the solar system and will never come back – unless retrieved by humans in the future.. They are still technically "falling", although they are now falling around the centre of our own Galaxy.
An Apollo spacecraft on the way to the moon was initially given enough velocity to enter earth orbit - where it "fell" around the earth at 17,500 mph. It was then given an extra boost to increase its velocity to 25,000 mph relative to the earth where it entered a trajectory away from the earth and towards the moon.
Technically, it was now in solar orbit but on a path that would intercept the moon's orbit. The moon's gravity would then cause it to loop around the moon and head back directly towards earth again. However, as it was looping around the moon, the Service Module engine was fired in a retrograde direction to slow the spacecraft to a speed where it would enter lunar orbit. It was now "falling" around the moon.
The Voyager space probes were given initial velocities of over 37,000 mph relative to the sun so that even the sun's gravity could not pull them back. There are therefore in a coasting free-flight out of the solar system and will never come back – unless retrieved by humans in the future.. They are still technically "falling", although they are now falling around the centre of our own Galaxy.
Eric Mc said:
A spacecraft in "coasting free flight" is travelling on a trajectory imparted upon it by some means of thrust – usually a rocket engine. Whether it is deemed to be "falling" or not really depends on where it is heading and what it is doing.
An Apollo spacecraft on the way to the moon was initially given enough velocity to enter earth orbit - where it "fell" around the earth at 17,500 mph. It was then given an extra boost to increase its velocity to 25,000 mph relative to the earth where it entered a trajectory away from the earth and towards the moon.
Technically, it was now in solar orbit but on a path that would intercept the moon's orbit. The moon's gravity would then cause it to loop around the moon and head back directly towards earth again. However, as it was looping around the moon, the Service Module engine was fired in a retrograde direction to slow the spacecraft to a speed where it would enter lunar orbit. It was now "falling" around the moon.
The Voyager space probes were given initial velocities of over 37,000 mph relative to the sun so that even the sun's gravity could not pull them back. There are therefore in a coasting free-flight out of the solar system and will never come back – unless retrieved by humans in the future.. They are still technically "falling", although they are now falling around the centre of our own Galaxy.
When apollo travelled to the moon did it travel in a spiral out from the earth? or did it travel in a straight line to meet up with the moon?An Apollo spacecraft on the way to the moon was initially given enough velocity to enter earth orbit - where it "fell" around the earth at 17,500 mph. It was then given an extra boost to increase its velocity to 25,000 mph relative to the earth where it entered a trajectory away from the earth and towards the moon.
Technically, it was now in solar orbit but on a path that would intercept the moon's orbit. The moon's gravity would then cause it to loop around the moon and head back directly towards earth again. However, as it was looping around the moon, the Service Module engine was fired in a retrograde direction to slow the spacecraft to a speed where it would enter lunar orbit. It was now "falling" around the moon.
The Voyager space probes were given initial velocities of over 37,000 mph relative to the sun so that even the sun's gravity could not pull them back. There are therefore in a coasting free-flight out of the solar system and will never come back – unless retrieved by humans in the future.. They are still technically "falling", although they are now falling around the centre of our own Galaxy.
Depends on your point of vew,. Relative to the earth/moon system - it travelled in a slightly curved path
You have to remember that the Apollo spacecraft intercepted the moon - which was also following its own orbital path around the earth. As it took three days to reach the vicinity of the moon, the Apollo spacecraft was not aimed directly at the moon itself, but at a point in the moons orbit ahead of the moon where the moon would arrive three days later.
You have to remember that the Apollo spacecraft intercepted the moon - which was also following its own orbital path around the earth. As it took three days to reach the vicinity of the moon, the Apollo spacecraft was not aimed directly at the moon itself, but at a point in the moons orbit ahead of the moon where the moon would arrive three days later.
There is strong and growing prospect that Carmelis 5D hypothesis may have a subtle truth in it, in that the 5th dimension may actually be that of gravity itself.
The amount of misunderstanding of how time fitted in to being a true 4th dimension of existence took Einstein, it will take an equally astonishing mind to integrate gravity as a true 5th dimension.
There isn't one and the hypothesis may even be wrong, but until that new Einstein materialises all discussion about Gravitation is a bit of groping in the dark.
The amount of misunderstanding of how time fitted in to being a true 4th dimension of existence took Einstein, it will take an equally astonishing mind to integrate gravity as a true 5th dimension.
There isn't one and the hypothesis may even be wrong, but until that new Einstein materialises all discussion about Gravitation is a bit of groping in the dark.
Bedazzled said:
That's a good spot, Carmeli's cosmological relativity does look interesting, but if I'm reading it right it uses cosmic expansion as the fifth dimension, rather than gravity?
I like the concept because, if correct, it does away with horrific dark energy and dark matter fudges in one fell swoop, and replaces them with some good old fashioned Einstein-like maths. It'll be interesting to see if it's adopted; if so I'll have to wait for the layman's guide before I can make much sense of it!
It does, in a way, but I think that is because we only relate to gravity in the negative, as an attractor, so to speak.I like the concept because, if correct, it does away with horrific dark energy and dark matter fudges in one fell swoop, and replaces them with some good old fashioned Einstein-like maths. It'll be interesting to see if it's adopted; if so I'll have to wait for the layman's guide before I can make much sense of it!
I have never held that to be the whole story.
I see Gravitation as a balance for time and its relativistic nature, in simple terms, a 5th dimension that accounts for the effect of Gravity by some greater overall Gravitational phenomena to even up the Cosmos, a Cosmological constant that is not constant but a metric or tensor.
I also see a 5th dimension as a way of harmonising the micro and macro cosmos that has so far hidden itself from us.
It is quite probable that any 5th dimension is also mono-polar and we see this as Gravity, the attractor.
I think a 5th dimension needs serious consideration and might explain mass too and we are looking at entirely the wrong thing when searching for a Higgs Boson, it is more likely to be a masked phenomenon and any higgs encountered just a residual of a greater interaction of the 5th dimension with the other 4.
It does rather nicely explain the only vestigial traces of a the Higgs, when it should be abundant, hugely abundant.
The scary bit is that I know someone, an outcast from conventional science, who has been on this track for 15 years and has tied a 5th dimension to supra-light interaction being responsible for mass and forecast years ago that the Higgs we'll find will be just a vestigial phenomenon. He's been right at every turn.
Munter said:
If we created a universe that consisted to just 2 atoms. And put them stationary 4.5 million light years apart. It would take 4.5 million years before they are attracted to each other?
In most popular theories, yes, we are expecting gravitational effects to propagate at ~c.Carmeli's theories are very interesting, and one which I expect to be adopted a little more often once it's fleshed out a bit, but without being a serious cosmologist or gravitational theorist I'm not sure if they're water tight.
Gassing Station | Science! | Top of Page | What's New | My Stuff