Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Can an Infinitely Long Object Fit in an Expanding Universe?   Does space stretch its contents as the universe expands? Usually we say the
answer is no - the stretching of space is not like the stretching of a rubber
sheet that might drag things with it. In this paper we explore a potential
counter example - namely we show that is is impossible to make an arbitrarily
long object in an expanding universe, because it is impossible to hold the
distant end of the object "stationary" with respect to us (as defined in the
Friedmann-Lemaitre-Robertson-Walker metric). We show that this does not mean
that expanding space has a force associated with it, rather, some fictitious
forces arise due to our choice of reference frame. By choosing our usual
time-slice (where all comoving observers agree on the age of the universe), we
choose a global frame that does not correspond to the frame of any inertial
observer. As a result, simple relativistic velocity transforms generate an
apparent acceleration, even where no force exists. This effect is similar to
the fictitious forces that arise in describing objects in rotating reference
frames, as in the case of the Coriolis effect.

16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas