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DEFINING THE EFFECTS OF SUB-CRITICAL COSMIC IMPACTS ON THE EARTH

Last Updated on Sunday, 02 May 2010 14:59
Published on Friday, 25 February 2005 00:00

 

DISCUSSION MEETING AT GEOLOGICAL SOCIETY, BURLINGTON HOUSE, PICCADILLY, LONDON W1.

"Sub-Critical Scale Impactors" i.e. near-Earth asteroids and small comets, will be the subject of a one-day discussion meeting in London on Friday December 11th as part of the Royal Astronomical Society's regular monthly programme. Media representatives are cordially invited to attend as observers.

The symposium brings together leading UK and French scientists to discuss the probability of such impacts, the different environmental and biological effects they create, and the known impact record on Earth.

Impacts have defined the evolution of life throughout the Earths history. At least one significant impact-related event has occurred in recent history, the explosion of a comet or asteroid over Tunguska in Siberia in 1908. There is no reason why a similar event could not eventually happen, through an accident of geometry and time, over London, Paris or New York.

Whilst a large impact could result in global devastation, the likelihood of Earth being struck by objects 10 km (6 miles) across is extremely remote - perhaps once every 50 million to 100 million years. On the other hand, much smaller, Tunguska-like events are expected to occur, on average, once every 50-100 years. Although these sub-critical impacts do not threaten large-scale extinctions, they are still likely to have significant effects on the surrounding environment. For example, it is now realised that the environmental effects of a SCI vary greatly depending on where the impactor lands.

The speakers at the symposium will discuss the hazard presented by these sub-critical impacts (SCIs) and the likely consequences for Earths climate and biosphere. In recent years this subject has developed into an important scientific discipline. The significance of comets and asteroids in the formation of the Earth, as well as the origin and evolution of life, has been increasingly recognised. According to one theory, most of Earths water was delivered by comets and flavoured with the building blocks of life brought by both asteroids and comets. However, only in the past few years has the reality and magnitude of the hazard presented by these objects been appreciated as evidence has been accumulated supporting the theory that a major impact 65 million years ago ended the rule of the dinosaurs and paved the away for the emergence of the mammals.

The meeting has been organised by Richard Taylor, David Hughes, and Julian Hiscox, under the auspices of the Royal Astronomical Society and the British Interplanetary Society (BIS).

An outline of the programme, and contact details for the organisers is given below. For further information on individual contributions, please contact the meeting organisers. ###

RAS/BIS/GS Joint Discussion meeting at the GEOLOGICAL SOCIETY LECTURE THEATRE BURLINGTON HOUSE, PICCADILLY, LONDON W1

FRIDAY 11th DECEMBER 1998

Organisers:
Dr. David Hughes, Dept. of Physics, University of Sheffield, Sheffield S3 7RH.
Tel: +44 (0)114-222-4288.
Fax: +44 (0)114-272-8079
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Dr. Julian Hiscox, IAH Compton Laboratory, Compton, Berkshire RG20 7NN.
Tel: +44 (0)1635-577274.
Fax: +44 (0)1635-577263
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Richard Taylor, Probability Research Group, 4 Abingdon Road, Norbury, London SW16 5QP.
Tel: +44 (0)181-764-2774.
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

PROGRAMME AND SPEAKERS.

FIRST SESSION - The Nature and Frequency of Small Impactors. Chairman: Dr. Julian Hiscox.

10:30 Dr. Matthew Genge (Natural History Museum) The implications of meteorites and micrometeorites for the nature of sub-critical impactors.

10:45 Mr. Jonathan Tate (Spaceguard UK) The frequency of SCI impactors with diameters in the 0.1 to 1km range

11:00 Dr. David Hughes (University of Sheffield) The cratering rate of planet Earth.

SECOND SESSION - Geological and Climatic Evidence. Chairman: Dr. David Hughes.

11:15 Professor Ian Smalley & Mr. Ian Jefferson (Nottingham Trent University)
Sedimentological consequences of sub-critical impacts in sandy deserts or loess regions.

11:30 Professor Nicholas Fedoroff - (Institut National Agronomique, France)
Registration of abrupt events in loess: around 67000 yrs BP (before present)transition reveals unusual attributes.

11:50 Professor Claudio Vita-Finzi (University College, London)
Seasonal enhancement and seismic triggering by impacts

12:05 Professor Chandra Wickramasinghe, M.K. Wallis and D.H. Wallis (University of Wales, College of Cardiff)
Climatic Switches Induced by Stratospheric Dust Loading.

12:20 Discussion.

12:35 LUNCH

THIRD SESSION - Evidence for Evolutionary and Recent Environmental Effects. Chairman: Professor Ian Smalley.

1:35 Dr. Norman MacLeod (Natural History Museum, London)
Identifying instances of past environmental change and their causal mechanisms.

1:55 Dr. Julian Hiscox (IAH Compton Laboratory)
Possible biochemical/bioevolutionary consequences of SCI events.

2:10 Dr. Marie-Agnes Courty (National Centre for Scientific Research, France)
Recognition of instantaneous soil collapse at 3950 BP (before present) throughout the Middle East in response to a blast wave, wild fires and heavy rains caused by an extra-terrestrial event.

2:30 Dr. Benjamin Peiser (Liverpool John Moores University)
Current research on Holocene impact events and its implications for impact rate calculations.

2:50 Dr. Victor Clube (Oxford University and Armagh Observatory)
Sub-cometary and sub-asteroidal impacts: historical considerations.

FOURTH SESSION - Wider Implications of Impacts. Chairman: Professor Claudio Vita-Finzi.

3:10 Professor Neville Price (formerly University College, London) Evidence for impact as a significant and periodic geological process.

3:25 Close.


Issued by:
Peter Bond, RAS Space Science Advisor
10 Harrier Close, Cranleigh,
Surrey, GU6 7BS, United Kingdom.
Phone: +44 (0)1483-268672
Fax: +44 (0)1483-274047
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.