Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The impact hazard from small asteroids: current problems and open
  questions   The current philosophy of impact hazard considers the danger from small
asteroids negligible. However, several facts claim for a revision of this
philosophy. In this paper, some of these facts are reviewed and discussed. It
is worth noting that while the impact frequency of Tunguska-like objects seems
to be higher than previously estimated, the atmospheric fragmentation is more
efficient than commonly thought. Indeed, data recorded from airbursts show that
small asteroids breakup at dynamical pressures lower than their mechanical
strength. This means that theoretical models are inconsistent with observations
and new models and data are required in order to understand the phenomena.

24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org