Event Horizon of Telescope Through Earth: Does It Exist?

In summary, the conversation discusses the possibility of using a telescope to observe stars on the other side of the Earth by drilling a hole through its center. One answer suggests that the telescope would have a limited range due to Earth's gravitational acceleration, while the other argues that this would not be a problem. The second answer is deemed correct as the observations are not local, and thus the equivalence principle does not apply.
  • #1
Tantal
1
0
Assume we drill a hole through the Earth - through the center towards the other side. Then we use a telescope, point it through the hole and observe stars on the other side of the earth. The telescope experiences a constant acceleration from Earth's gravitation. Accelerated movements have an event horizon. Is the sight of our telescope limited by this horizon?

Answer #1: Yes. The telescope experiences a constant acceleration of 1g, so any star beyond the distance d=c^2/9.81 (~ one light year) is not visible. Furthermore, Einstein's equivalence principle (the comparison with an accelerated rocket) favors this answer.

Answer #2: No. The position of the telescope relatively to the stars does not change. It is the same as for any other position on Earth's surface, so Earth's gravitational accelaration does not matter. Furthermore, there would be no problem for another telescope on the far end of the hole in observing faraway stars. The photons of such stars which made it up to the far end telescope should have no troubles to pass the rest of their journey through the hole - like photons of a flash light positioned at the far end of the hole.

Because of the flash light argument Answer #2 seems to be the only choice. But then Einstein's equivalence would not hold. Where is the flaw in these answers?
 
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  • #2
Tantal said:
Because of the flash light argument Answer #2 seems to be the only choice.

Yes, answer #2 is correct. Answer #1 would be correct if spacetime were flat, but it isn't.

Tantal said:
But then Einstein's equivalence would not hold.

The observations you are talking about are not local; they are not confined to a small enough region of spacetime that tidal gravity is negligible. So the EP does not apply, and the observations you describe do not mean the EP does not hold.
 

FAQ: Event Horizon of Telescope Through Earth: Does It Exist?

1. What is the "Event Horizon of Telescope Through Earth"?

The "Event Horizon of Telescope Through Earth" is a hypothetical boundary in space that marks the point of no return for light entering a telescope placed at the center of the Earth. It is the distance at which light rays are bent so much that they cannot escape and are trapped within the Earth's gravitational pull.

2. Does the "Event Horizon of Telescope Through Earth" actually exist?

There is currently no scientific evidence to suggest that the "Event Horizon of Telescope Through Earth" exists. It is a theoretical concept that has not been proven or observed in reality. However, it is still a topic of ongoing research and debate among scientists.

3. How would the "Event Horizon of Telescope Through Earth" impact our understanding of the universe?

If the "Event Horizon of Telescope Through Earth" were to exist, it would have significant implications for our understanding of the universe. It could potentially allow us to observe objects and events that are currently invisible to us, such as the center of the Milky Way galaxy or distant galaxies beyond our current observable range.

4. Is it possible for us to create a telescope that can penetrate the "Event Horizon of Telescope Through Earth"?

Creating a telescope that can penetrate the "Event Horizon of Telescope Through Earth" is currently beyond our technological capabilities. The immense gravitational forces at the center of the Earth would make it extremely difficult, if not impossible, to build a telescope that could withstand the pressure and still function effectively.

5. What other factors should be considered when discussing the "Event Horizon of Telescope Through Earth"?

Aside from the technical and theoretical aspects, there are also ethical and practical considerations to be taken into account when discussing the "Event Horizon of Telescope Through Earth". For example, the potential impact on the Earth's environment and potential hazards to human life would need to be thoroughly evaluated before any attempts to create such a telescope could be made.

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