What Happens to a Baseball Thrown from a Light Speed Ship?

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Discussion Overview

The discussion revolves around the hypothetical scenario of throwing a baseball from a spaceship traveling at light speed and the implications of relativistic physics on such an event. Participants explore concepts related to velocity addition, the nature of light, and the relativistic effects observed by different observers in various frames of reference.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions why objects cannot exceed the speed of light and proposes a scenario involving throwing a baseball from a light-speed spaceship.
  • Another participant references the velocity addition formula, suggesting that the baseball's speed would not exceed the speed of light from any observer's perspective.
  • A participant clarifies that observers on Earth would see the baseball moving at a speed less than the speed of light due to time dilation effects as the spaceship approaches light speed.
  • Concerns are raised about the use of Galilean transformation instead of Lorentz transformation for high-speed scenarios, emphasizing the need for relativistic calculations.
  • One participant discusses the misunderstanding of relative motion and how different observers perceive the speed of the baseball and the effects of time dilation.
  • A participant introduces a new scenario involving firing a laser beam from a spaceship traveling at near light speed towards a satellite, questioning the timing of the laser's impact relative to the ship's arrival.
  • Another participant emphasizes the importance of specifying the frame of reference when discussing relative speeds and the implications of Doppler effects on the observed energy of the laser beam.

Areas of Agreement / Disagreement

Participants exhibit multiple competing views regarding the implications of relativistic physics on the scenario of throwing a baseball and firing a laser. There is no consensus on the interpretations of the effects of speed and relativity, and the discussion remains unresolved.

Contextual Notes

Participants note limitations in understanding the effects of relativistic speeds, particularly regarding the assumptions about frames of reference and the application of different transformation equations. The discussion highlights the complexity of visualizing events at relativistic speeds and the need for precise definitions in such scenarios.

Who May Find This Useful

This discussion may be useful for individuals interested in the principles of relativity, the nature of light, and the complexities of motion at high speeds, particularly in the context of theoretical physics scenarios.

parkland
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Just a random thought or question.
Why can't something go faster than the speed of light?
It almost seems like some laws of energy or physics do not agree with light speed.

Consider this; imagine Earth pays to construct a light speed ship, and sends me up with a baseball.
Once at lightspeed, I go outside, standing in my space suit, and throw the baseball ahead.
Now the baseball is traveling at lightspeed + 40 mph.

Every piece of science seems to deny that my ball could travel over the speed of light.

So then what happens to the ball? We're at 0 G's, I throw it, and it just stays in space where I let go of it? That doesn't make sense either.
I exert a force on it, so it should react. It should move where I throw it, unless some other force disables it from doing so, like a wall, or water.

So what would happen to the baseball thrown ahead of a spaceship traveling at light speed?
 
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parkland said:
Now the baseball is traveling at lightspeed + 40 mph.
...
So what would happen to the baseball thrown ahead of a spaceship traveling at light speed?
You've skipped a step here.

Here's the short answer:

1] You, on the spaceship see the baseball moving at 40 mph. No violation there.
2] People on Earth see the spaceship traveling at .999c with a baseball moving at .9999c. Still no violation.

The key is that, as you and your spaceship approach the speed of light, Earth will see time for you slow. So, in slow motion, they see you throw a baseball at merely 0.1 mph. They never see a baseball exceed c.

(The numbers are wild approximations, merely for the sake of clarity.)
 
Last edited:
parkland said:
Once at lightspeed, I go outside, standing in my space suit, and throw the baseball ahead.

You're displaying a common misunderstanding that everyone's motion is relative to a universal, "common" frame of reference. First of all, you can't get to lightspeed, so your example fails right there, but let's say you are going very close to lightspeed, say 0.99c. But that would be a speed, say, that was seen by me watching you move through space. According to you, though, you are not moving at 0.99c, according to you, you are not moving at all, you are at rest. So when you throw your ball, you're going to see it travel not at 0.99c + 40 mph, you're going to see it travel at 40 mph relative to your velocity, which is zero. So, you will see it travel at 40 mph. I, on the other hand, looking at you throw the ball, will see you basically in slow motion throwing the ball, and I will see it leave your hand and move forward from you at a velocity faster than what you are traveling at from my perspective, but it will move forward very slow compared to you and won't ever reach what I perceive to be the speed of light.
 
Wow cool, I love all the thought in here!
I am trying to grasp and comprehend a few things here still.
This is a very tough concept for me to grasp.

So here is where I'm at.

If I am traveling at .999 light speed, towards a slow object, say an Earth orbit satellite, which is near 0 speed relative to me on my space ship, and I fire a laser beam at it, 299 792 458 meters from it, does my laser light strike the satellite before my ship does?

If I understand correctly, if I was sitting on the satellite, I would see the laser light leave the laser transmitter in slow motion, as the ship hit's me directly behind that.
However, if sitting on the spaceship firing the laser, I would see the laser light emit from the transmitter for an entire second before impact.

To make it even weirder, what if someone had a series of hypothetical telescopes from a few light years away, and they could view this event, what would it look like to them?
 
parkland said:
If I am traveling at .999 light speed, towards a slow object, say an Earth orbit satellite, which is near 0 speed relative to me on my space ship, and I fire a laser beam at it, 299 792 458 meters from it, does my laser light strike the satellite before my ship does?
You always have to be clear about what a speed is relative to. Are you trying to say that the you are moving at a speed of .999c relative to the satellite? If so we can describe that situation as either the satellite at rest while you approach it at .999c, or as you at rest while the satellite is moving towards you at .999c (and a third observer not at rest relative to either of you would say that you're both moving towards one another, possibly at different speeds). If that's not what you meant, then the problem is still underspecified - you have to tell us what the satellite is "moving slowly" relative to.

If I understand correctly, if I was sitting on the satellite, I would see the laser light leave the laser transmitter in slow motion, as the ship hit's me directly behind that.
However, if sitting on the spaceship firing the laser, I would see the laser light emit from the transmitter for an entire second before impact

Assuming that problem is as I described above:

You in the ship will fire your laser beam for one second, starting when the satellite is one light-second 299 792 458 meters) away and ending when the satellite is .001 light-seconds away. About a millisecond after that, the satellite will impact your ship.

Satellite guy will describe the situation as you approaching him at .999c; the leading of the laser pulse won't even reach him until you are a mere .001 light-seconds away and about one millisecond before impact. All the energy of the entire laser pulse will arrive during that millisecond. Thanks to the doppler effect (google for "doppler effect" if you are not familiar with that term) the incoming radiation will be enormously blue-shifted relative to satellite guy, so delivers much more energy per unit time and ends up delivering the same total amount of energy.
 

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