I agree with what what little you've said ##-## it looks to me like you haven't actually posed a well-formed question ##-## yes, to have a length dimension, you need at least one point to start with, and another for extension, right? What question was posed to you?rgtr said:
I've been on PF a long time. If I had described an event with any less than 4 coordinates, I'd bet my pretty blue bonnet someone would step in with "Welll, ACKtually..."sysprog said:Wow, @DaveC426913, I think that you're not wrong to go to 4d, but I wanted to be gentle and stay 1d and 2d for a minute first.
[EDIT]Maybe it should have been said as 'fewer than' rather than "less than", given that "4" is a number of co-ordinates in your remark here, and not an amount ##-## yes, I'm being fussy ##\dots##DaveC426913 said:
I imagine, as apparently you do, that we haven't been given the entirety of the original question.hmmm27 said:
An event has "position", not "length". It answers the question: "where was it?", not "how big was it?"rgtr said:
Not exactly I was reading a book and just was confused by this.hmmm27 said:
So - for context - what was the (book) question/statement that elicited the confusion ?rgtr said:
What book? You have a book that says an event has a length of zero but also has a length L (that is not zero)?rgtr said:
Thanks for now having given us that link to the book chapter https://scholar.harvard.edu/files/david-morin/files/relativity_chap_1.pdf ##-## it said parenthethically on page 13 of 70:rgtr said:
An event can have both length and time because these are two fundamental properties of the universe. Length refers to the physical distance between two points, while time is the measure of the duration of an event. Both of these properties are necessary to fully describe the motion and interactions of objects in the universe.
An event having L = 0 means that the length of the event is equal to zero. This can occur in situations where the two points involved in the event are at the same location, resulting in a distance of zero between them. For example, if an object remains stationary at a single point, the length of its event would be equal to zero.
Yes, an event with L = 0 can still have a duration in time. This is because time is a separate property from length and can still be measured even if the length of the event is equal to zero. For example, a stationary object may still experience changes in time, such as aging or the passing of seconds.
The concept of L = 0 is a fundamental principle in the theory of relativity. In special relativity, the length of an event can appear differently to observers depending on their relative motion. However, the duration of the event will always be the same for all observers, regardless of their frame of reference. This is known as time dilation and is a key component of the theory of relativity.
Yes, there are real-life examples of events with L = 0. One example is the collision of two subatomic particles, such as protons, in a particle accelerator. In this case, the particles are so small and moving at incredibly high speeds that the length of the event of their collision can be considered negligible. Another example is the formation of a black hole, where the matter collapses to a single point and the length of the event becomes zero.