Traveling in space

[brianb]

If there's no atmosphere in space and no friction, then could a space craft be fired in space to go 10,000 mph and shut off the engine/thrust and travel at 10,000mph forever or until it stopped or was hit by something?

[Doum]

yes brianb,

The space craft will go at same speed forever in theory. In reality, the ship might loose speed due to gravity of a planet or a moon or a sun. If the ship acheive the orbital speed of a planet and it is high enough over the planet atmosphere it will cruise at same speed for almost forever with his engine shut off (Spaceshuttles are doing it all the time when in orbit around the earth.). It might hit sumthing the next day in a few century or millenium or not. In the vacuum of space any ship will always keep his speed steady when engine off if it has the right speed to keep it orbit around a celestial body (Earth, moons ,planets or sun.).

[harry]

Hello All

Speed is relative to your surroundings.

You maybe travelling at 35,000 Kms and your rocket may add another 25,000 kms relative to earth.

You may come across another solar system going in the same direction at the same speed and your speed maybe zero relative to it.

[kovil]

<< shut off the engine/thrust and travel at 10,000mph ... until it ...was hit by something? >> or acted upon by a force like gravity.

Yes, that's Inertia or Momentum. As Newton described it "the tendency to stay in motion, or to remain at rest; until acted upon by something else."

In a new description of the Universe/Reality; Inertia/Momentum is called 'The Changeless'.

The Changeless, that underlying principle or quality, which shows through into this Universe and we see it as Inertia/Momentum.

Physics can describe how inertia and momentum behave and act, but Physics has no answer as to why the qualities of inertia and momentum exist.

[harry]

Hello All


Kovil said

Physics can describe how inertia and momentum behave and act, but Physics has no answer as to why the qualities of inertia and momentum exist.

In the meaning of the word,,,,,,,,,,,,,,,you are right.

There are some theories as to the WHY?

[harry]

Hello All

I came across this link:

Interesting reading of things to come.

Variable-Specific-Impulse Magnetoplasma Rocket
This rocket is expected to enable long-term human exploration of outer space.

http://www.nasatech.com/Briefs/Sep01/MSC23041.html

Johnson Space Center has been leading the development of a high-power, electrothermal plasma rocket — the variable-specific-impulse magnetoplasma rocket (VASIMR) — that is capable of exhaust modulation at constant power. An electrodeless design enables the rocket to operate at power densities much greater than those of more conventional magnetoplasma or ion engines. An aspect of the engine design that affords a capability to achieve both high and variable specific impulse (Isp) places the VASIMR far ahead of anything available today. Inasmuch as this rocket can utilize hydrogen as its propellant, it can be operated at relatively low cost.

Mini-Magnetospheric Plasma Propulsion (M2P2)
http://www.ess.washington.edu/Space/M2P2/

Mini-Magnetospheric Plasma Propulsion (M2P2) is an advanced plasma propulsion system that will enable spacecraft to attain unprecedented speeds, with minimal energy and mass requirements. It will create a large scale magnetic bubble around the spacecraft to ride the solar winds, and accelerate the spacecraft to unprecedented speeds.

University of Illinois, Air Force Researchers Release Study of Focus Fusion for Space Propulsion.
http://focusfusion.org/log/index.php/si ... ropulsion/

[Hawkgirl]

Is there something in the universe we can use to measure our speed against? Not relative to a planet or galaxy but something that no matter where you go you can say "I'm going X miles per hour" regardless of your velocity or direction of travel?

[BMAONE23]

Seeing as the speed of sound fluctuates relative to atmospheric density, temperature, relative humidity, etc., and the speed of thought changes relative to the blood levels of Ginko Biloba, or alcohol, or Viagara,...
I would imagine that the only absolute speed marker is that of light so the only way to tell relative speed would be VIA red shifting of light sources that you are leaving behind. The further red shifted they become, the faster you are traveling away from them. Blue shift could be used similarly for light sources you are approaching. (though a good baseline would be needed for individual sources). The only other way to tell is kind of after the fact, and that would be by using the ammount of time taken to cover a certain distance through space.

Any other ways that I do not know of???
(I'm not the most versed on space travel and speed vs distance.)

[harry]

Hello All

We could measure the speed of

Earth around sun.
Sun around Milky Way
Milky way around local cluster
Local Cluster aroun larger cluster of clusters.
Larger clusters around super clusters
Super clusters around super dooper clusters.

Where does it end? We are part of something big and its not the Big Bang.

[kovil]

The only thing that stays 'fixed' in relationship to everything around us and near and even relatively far away, is the border of our awareable universe. But that is at least 15 billion light years away and maybe 120 billion light years away. So it is a tough rebound to echo off of for a fix, and that leaves us in a practical sea of relative relationships for proximities.

[harry]

Hello Kovil

All objects in the universe want to be together.

Everything forms units. If our observable universe forms a unit combining all the super clusters of clusters of clusters of galaxies. Than that imaginary border may exist.

It would make the wall of china look very small.

Harlow Shapley's determination of the size of the Galaxy.

http://zebu.uoregon.edu/~soper/MilkyWay/shapley.html

I was looking for another link,,,,,,,,,,,,canot find it.

Missing link