Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cataclysm no more: New views on the timing and delivery of lunar
  impactors   If properly interpreted, the impact record of the Moon, Earth's nearest
neighbour, can be used to gain insights into how the Earth has been influenced
by impacting events since its formation ~4.5 billion years (Ga) ago. However,
the nature and timing of the lunar impactors - and indeed the lunar impact
record itself - are not well understood. Of particular interest are the ages of
lunar impact basins and what they tell us about the proposed "lunar cataclysm"
and/or the late heavy bombardment (LHB), and how this impact episode may have
affected early life on Earth or other planets. Investigations of the lunar
impactor population over time have been undertaken and include analyses of
orbital data and images; lunar, terrestrial, and other planetary sample data;
and dynamical modelling. Here, the existing information regarding the nature of
the lunar impact record is reviewed and new interpretations are presented.
Importantly, it is demonstrated that most evidence supports a prolonged lunar
(and thus, terrestrial) bombardment from ~4.2 to 3.4 Ga and not a cataclysmic
spike at ~3.9 Ga. Implications for the conditions required for the origin of
life are addressed.

36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph