Good Morning,
It is Sunday and it is very nice outside this morning, 38 degrees and blue skies. I feel good even with the TV on this Sunday morning. I normally post my blog in quiet so as to sense the morning as a prayer of being life on the planet earth. The planet is moving very fast around the sun but fast out there where their is little friction does not bother our atmosphere and gravity.
Why not? I have no clue? Somebody explain to me why there is friction here near my feet and none above the atmosphere. I do have a place to look and maybe I will understand.
***
Acceleration and Velocity in Space
Question:
It's my understanding that if a space-going vessel continued to burn its engines non-stop, then regardless of the power of the engines (or the fuel used) the vessel would continue to accelerate until the fuel ran out. Then it would coast at a constant speed. A friend said that this is incorrect and that each fuel used in space has a maximum speed, and that once that speed is attained the vessel will be at a constant speed, even if the engines are on continuously. Which is true?
Answer:
The short answer is, "You're right and your friend is wrong."
This question was answered by Newton when he concluded that acceleration (and not velocity) was proportional to the force applied to an object. Another of his laws was that once set in motion (such as when a spacecraft is coasting after burning its fuel), the object travels in a straight line at a constant speed unless acted upon by another force.
Probably the greatest reason for misunderstanding this aspect of classical physics is the modern car. We know that to drive at a constant speed we need to burn fuel. What we forget is that a moving car experiences friction in the form of air resistance. The soft tires also consume energy as they flex and turn. The fuel burned in the engine is overcoming those forces to allow the car to move at a constant speed.
Newton would have loved space. There is no air resistance. There is only gravity. Once a spacecraft is accelerated to a given speed, the engine is turned off and the craft coasts forever with its trajectory affected only by the force of gravity.
The best example of this I know is the Voyager 1 & 2 spacecraft. They were launched in 1977 and went to Jupiter and Saturn. Voyager 2 went on to Uranus and Neptune. Their trajectories were affected by gravity during their swings past the planets, but they continue to coast ever outward. Today they are nearly 90 times as far from the Sun as is the Earth and probing the region where space dominated by our Sun meets interstellar space. And on they coast, not burning any fuel. They move at a constant velocity, looking, recording, and teaching us more every day.
So you see, the beauty of space is that it is really much simpler than physics here on Earth.
Dr. Charles Smith
(June 2004)"
Why not? I have no clue? Somebody explain to me why there is friction here near my feet and none above the atmosphere. I do have a place to look and maybe I will understand.
***
Acceleration and Velocity in Space
Question:
It's my understanding that if a space-going vessel continued to burn its engines non-stop, then regardless of the power of the engines (or the fuel used) the vessel would continue to accelerate until the fuel ran out. Then it would coast at a constant speed. A friend said that this is incorrect and that each fuel used in space has a maximum speed, and that once that speed is attained the vessel will be at a constant speed, even if the engines are on continuously. Which is true?
Answer:
The short answer is, "You're right and your friend is wrong."
This question was answered by Newton when he concluded that acceleration (and not velocity) was proportional to the force applied to an object. Another of his laws was that once set in motion (such as when a spacecraft is coasting after burning its fuel), the object travels in a straight line at a constant speed unless acted upon by another force.
Probably the greatest reason for misunderstanding this aspect of classical physics is the modern car. We know that to drive at a constant speed we need to burn fuel. What we forget is that a moving car experiences friction in the form of air resistance. The soft tires also consume energy as they flex and turn. The fuel burned in the engine is overcoming those forces to allow the car to move at a constant speed.
Newton would have loved space. There is no air resistance. There is only gravity. Once a spacecraft is accelerated to a given speed, the engine is turned off and the craft coasts forever with its trajectory affected only by the force of gravity.
The best example of this I know is the Voyager 1 & 2 spacecraft. They were launched in 1977 and went to Jupiter and Saturn. Voyager 2 went on to Uranus and Neptune. Their trajectories were affected by gravity during their swings past the planets, but they continue to coast ever outward. Today they are nearly 90 times as far from the Sun as is the Earth and probing the region where space dominated by our Sun meets interstellar space. And on they coast, not burning any fuel. They move at a constant velocity, looking, recording, and teaching us more every day.
So you see, the beauty of space is that it is really much simpler than physics here on Earth.
Dr. Charles Smith
(June 2004)"
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