Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Larger Estimate of the Entropy of the Universe   Using recent measurements of the supermassive black hole (SMBH) mass
function, we find that SMBHs are the largest contributor to the entropy of the
observable universe, contributing at least an order of magnitude more entropy
than previously estimated. The total entropy of the observable universe is
correspondingly higher, and is S_obs = 3.1+3.0-1.7x10^104 k. We calculate the
entropy of the current cosmic event horizon to be S_CEH = 2.6+-0.3x10^122 k,
dwarfing the entropy of its interior, S_CEHint = 1.2+1.1-0.7x10^103 k. We make
the first tentative estimate of the entropy of weakly interacting massive
particle dark matter within the observable universe, S_dm = 10^87-10^89 k. We
highlight several caveats pertaining to these estimates and make
recommendations for future work.

2
The categories of this paper are: math
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin