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Snip3r
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if i were to leave Earth travel in as straight a line as possible with constant velocity eventually i would return to earth.
is mine a valid inertial frame?
is mine a valid inertial frame?
What evidence do you have for this assertion?Snip3r said:if i were to leave Earth travel in as straight a line as possible with constant velocity eventually i would return to earth.
In special or general relativity?is mine a valid inertial frame?
Snip3r said:if i were to leave Earth travel in as straight a line as possible with constant velocity eventually i would return to earth.
Snip3r said:if i were to leave Earth travel in as straight a line as possible with constant velocity eventually i would return to earth.
is mine a valid inertial frame?
elfmotat said:WMAP has confirmed that the universe is flat to within about ±0.5%. If the universe is flat then you can't travel in a "straight" line and return to your original location.
morfin56 said:Of coarse not you would eventually wander into another galaxy/
phinds said:Only if it is unbounded. My understanding is that flat and bounded are possible, in which case you most certainly would, in theory, return.
DrGreg said:Actually, even if the Universe is bounded, you'd never make the journey all the way round it because it's expanding too fast. There are distant parts of the Universe we cannot see because the light from there is traveling slower than the rate of expansion.
Matterwave said:Do you have a reference to "flat and bounded"? As far as I know, a flat metric would have a 3-volume which would integrate to infinity:
[tex]a(t_0)\int_{-\infty}^{\infty} dxdydz\rightarrow\infty[/tex]
George Jones said:A flat FRW universe satisfies the cosmological principle, i.e., is spatially homogeneous and isotropic, and has space topologically equivalent to R^3. Either of these principles can be relaxed. A flat, homogenous, non-isotropic universe can have space topologically equivalent to the 3-torus T^3. See chapter of Gron and Hervik,
Einstein's Einstein's equation doesn't determine the topology of spacetime.
An inertial frame is a coordinate system in which the laws of physics hold true and objects move at a constant velocity unless acted upon by an external force. This means that there is no acceleration or rotation in the frame, and all measurements are relative to this frame.
In this scenario, the traveler would be moving at a constant velocity in a straight line, experiencing no acceleration or rotation. This would require a very powerful and efficient means of propulsion, such as a spacecraft with advanced propulsion systems. The journey would also involve navigating through various gravitational fields and avoiding collisions with any celestial bodies.
Some potential challenges include the immense distance and time involved in traveling around the entire universe, the need for advanced technology and resources, and potential risks such as collisions with debris or encountering unknown phenomena. The effects of long-term exposure to radiation and microgravity on the human body may also pose challenges for the traveler.
At this point in time, it is not possible for humans to achieve a trip around the entire universe in an inertial frame due to the limitations of technology and resources. However, with advancements in space travel and propulsion systems, it may become a possibility in the distant future.
A journey like this would provide valuable insights and data about the vastness and complexity of our universe, including the various celestial bodies, gravitational fields, and potentially unknown phenomena. It could also help us better understand the laws of physics and potentially lead to new discoveries and advancements in science and technology.