- #1
JohnnyGui
- 796
- 51
Good day to you all,
I have been reading Stephen Hawking's book "A Briefer History of Time" (yes, I'm a novice ;)) and I need some verification on if my understanding is correct regarding his theory/conclusion saying that if one travels faster-than-light, he would be able to travel into the past and that the order of events would differ for 2 observers with different velocities.
Here's what he says:
- Event A occurs on Earth
- Event B occurs on Proxima Centauri (PC) one year later Earth's time after event A
- Earth and PC are 4 light-years apart
- In order for an observer on Earth to experience both events, he'd have to travel faster than light to PC after event A occurs
If my understanding is correct, does this mean that the observer, while going faster-than-light during his travel to PC, he would "pass" the lightbeams of event A going to PC along with him? He'd then reach PC, experience event B and then receive the lightbeams of event A afterwards? Wouldn't he be experiencing the events in the order [A (when he was on Earth)] - B - [A (receiving the lightbeams while standing on PC)]? Is my statement correct as to what he meant with traveling to the past by going faster-than-light?
The part after that makes less sense to me, it's about an observer standing on PC and moving away from Earth at light speed:
"This observer would say it is possible, if you could move faster than light, to get from event B to event A. In fact, if you went really fast, you could also get back from A to PC before that event."
How is it possible for that observer standing on PC, who already experienced event B on PC, to experience event A on Earth after B while event A already happened 1 year Earth's time before event B? Or does he mean that, by going faster-than-light away from PC, he'd "pass" the lightbeams of Event B, then he'd meet during his travel to Earth the lightbeams of event A that approaches him and then receive the lightbeams of event B afterwards?
Are my statements correct? If not, could one please explain to me in layman terms what he really meant?
I have been reading Stephen Hawking's book "A Briefer History of Time" (yes, I'm a novice ;)) and I need some verification on if my understanding is correct regarding his theory/conclusion saying that if one travels faster-than-light, he would be able to travel into the past and that the order of events would differ for 2 observers with different velocities.
Here's what he says:
- Event A occurs on Earth
- Event B occurs on Proxima Centauri (PC) one year later Earth's time after event A
- Earth and PC are 4 light-years apart
- In order for an observer on Earth to experience both events, he'd have to travel faster than light to PC after event A occurs
If my understanding is correct, does this mean that the observer, while going faster-than-light during his travel to PC, he would "pass" the lightbeams of event A going to PC along with him? He'd then reach PC, experience event B and then receive the lightbeams of event A afterwards? Wouldn't he be experiencing the events in the order [A (when he was on Earth)] - B - [A (receiving the lightbeams while standing on PC)]? Is my statement correct as to what he meant with traveling to the past by going faster-than-light?
The part after that makes less sense to me, it's about an observer standing on PC and moving away from Earth at light speed:
"This observer would say it is possible, if you could move faster than light, to get from event B to event A. In fact, if you went really fast, you could also get back from A to PC before that event."
How is it possible for that observer standing on PC, who already experienced event B on PC, to experience event A on Earth after B while event A already happened 1 year Earth's time before event B? Or does he mean that, by going faster-than-light away from PC, he'd "pass" the lightbeams of Event B, then he'd meet during his travel to Earth the lightbeams of event A that approaches him and then receive the lightbeams of event B afterwards?
Are my statements correct? If not, could one please explain to me in layman terms what he really meant?