Post on 25-Jul-2015
How to predict How to predict the size of an the size of an
asteroid crater?asteroid crater?
Lycée Doisneau – Vaulx-en-VelinFrance
International International Express YourselfExpress Yourself Conference ConferenceSheffield Hallam University – May 13, 2014Sheffield Hallam University – May 13, 2014
Rémi GUILLETAmani HAMDI
Amel MAHAMDITahanie MEJRI
Zeynep SAN
Spokespersonsof a group of 45 French students
Our hometown is located next to Lyon
Lyon
Lyonthe 2nd biggest city in France
Vaulx-en-Velinin the suburbof Lyon
Paris
Our school : the Lycée Doisneau
« We have nothing to fear but… »
Albert UDERZO, Asterix and the falling sky, 2005
How to predict the size of an How to predict the size of an asteroid crater?asteroid crater?
1. Problem presentation
Localisation of the asteroids
A picture of the solar systemhttp://www.nasa.gov
Map of the asteroidsin the inner solar system
restated on May 9, 2008 http://www.greatdreams.com/near.htm
Diversity of the asteroids
http://www.paperblog.fr/4691619/la-sonde-spatiale-dawn
ObjectName
Close Approach Date
Close Approach Distance (LD*)
EstimatedDiameter
RelativeSpeed (km/s)
(2008 TA1) 2014-05-13 58.2 480 m - 1.1 km 14.57
(2013 WU44) 2014-05-15 63.4 180 m - 410 m 11.24
342866 (2008 YU32) 2014-05-15 57.5 240 m - 540 m 14.04
(2010 SO16) 2014-05-16 65.6 210 m - 470 m 10.02
(2010 JO33) 2014-05-17 4 27 m - 59 m 8.19
(2007 VD12) 2014-05-17 62.3 270 m - 590 m 13.11
(2014 FP47) 2014-05-18 37.4 88 m - 200 m 5.64
(2014 GD50) 2014-05-19 38.4 280 m - 630 m 23.98
(2013 XS23) 2014-05-19 46.5 15 m - 33 m 5.83
225312 (1996 XB27) 2014-05-20 44.8 110 m - 240 m 0.84
242708 (2005 UK1) 2014-05-20 36.7 670 m - 1.5 km 19.57
(2011 JR13) 2014-05-21 19.7 320 m - 710 m 27.19
21374 (1997 WS22) 2014-05-21 47.1 920 m - 2.1 km 12.54
(2010 UQ7) 2014-05-21 50.2 270 m - 590 m 20.63
(2014 FA44) 2014-05-23 14.7 28 m - 63 m 2.37
(2007 VK184) 2014-05-23 67.3 110 m - 240 m 20.72
(2000 TL1) 2014-05-23 64.9 73 m - 160 m 11.92
One near-Earth object every day !Upcoming close approaches to Earth
* 1 LD = Lunar Distance ≈ 385 000 km http://neo.jpl.nasa.gov/ca/
Next saturday
ObjectName
Close Approach Date
Close ApproachDistance (LD)
EstimatedDiameter
RelativeSpeed (km/s)
(2010 JO33) 2014-05-17 4 27 m - 59 m 8.19
Our problem
If this asteroid (as big as a building)crashed on Earth,
what would be the size of the impact crater?
http://www.intellego.fr/aide-scolaire-svt/photos-meteor-crater-barringer
How to predict the size of an How to predict the size of an asteroid crater?asteroid crater?
1. Problem presentation
2. Experimental design
Impact crater simulation
Situation studied Simulation
Impactor Asteroid MarbleImpact surface Earth (rocks) Basin of flour, sand, compost...
Principle of the experiment
Influential variables
fixed: flat and horizontal ground
fixed: vertical fall
varying: flour, semolina, sand, (compost, sawdust...)
varying: from 30 cm to 2 m
fixed: spherical
A few trials with different balls, then fixed: a big glass marble of 21 g
Formation of an impact crater
Vincent Langlois,from the Geology Laboratory of the University of Lyon
http://ufe.obspm.fr
Necessity to choose a powdering ground
Wet sandSoft clay
http://cm1cm2.ceyreste.free.fr/formes.html http://www.impact-structures.com
How to predict the size of an How to predict the size of an asteroid crater?asteroid crater?
1. Problem presentation
2. Experimental design
3. Observations and measurements
Experimental procedure
Visual observations
=> There is evidence of matter ejection during the impact.
Measurements
Flour + layer of cacao powder
E=m⋅g⋅h
A marble dropped from the height hcrashes on the flour with the energy where m is the mass of the marble (kg), g is the gravitational field strength (on Earth, g = 9,81 N/kg),
h is the height of the fall (m) E is the energy (J)
E=m⋅g⋅h
MeasurementsFine semolina
Medium-grained semolina Sand
How to predict the size of an How to predict the size of an asteroid crater?asteroid crater?
1. Problem presentation
2. Experimental design
3. Observations and measurements
4. Data analysis
Evolution of the crater diameter depending on the marble energy
The finer the soil texture, the larger the crater.The points have a regular and accurate evolution when the soil is the fine semolina. The
software LibreOffice calculated the equation of the best fit curve:
D = 0.12 E 0.26
D = 0.12 E 0.26
Best fit curve (flour)
Best fit curve (fine semolina)
Best fit curve (medium semolina)
Best fit curve (sand)
ObjectName
Close Approach Date
Close ApproachDistance (LD)
EstimatedDiameter
RelativeSpeed (km/s)
(2010 JO33) 2014-05-17 4 27 m - 59 m 8.19
Extrapolation: principle
We are going to make the hypothesis that when an asteroid crashes on Earth, it is like when a marble falls in fine semolina. Therefore, the crater diameter (D in meter) is related to the asteroid energy (E in Joule) by the formula D = 0.12 E 0.26 .
BACK TO THE PROBLEM
=> First, thanks to the data of the table, we are going to calculate the energy E of the asteroid.
=> Then, we are going to use the formula we have established (D = 0.12 E 0.26) to find the crater diameter D.
Next saturday
D=0.12×(6.7×1015)0.26≈1.6×103 m≈1.6 km
Extrapolation: application
Volume V of the asteroid which will approach next saturday (diameter: 50 m)
V = 43
R3 V = 43
π( 502
)3
=65×103 m 3
Mass m of the asteroid
Density of the asteroid: ρ ≈ 3.0 103 kg/m3 (like Earth's rocks)
m=3.0×10 3×65×103≈ 2.0×108 kg
Energy E of the asteroid (velocity: 8.19 km/s)
E=12
mv² E=12×2.0×108×(8.19×103)²=6.7×1015 J
Diameter D of the impact crater
D=0.12×E 0.26
Comparison of our resultswith those of scientists
What we have found
A 50 meter-diameter asteroid makes a 1.6 kilometer-wide crater.
Elements of comparison
The same order of magnitude
Automatic calculations
How to predict the size of an How to predict the size of an asteroid crater?asteroid crater?
1. Problem presentation
2. Experimental design
3. Observations and measurements
4. Data analysis
5. Conclusion
Conclusion
What we found- we can simulate an impact crater at a small scale using semolina instead
of rocks- we can predict the diameter D of the crater resulting from the impact of an
asteroid releasing the energy E, using the equation D = 0.12 E 0.26
Limitations of the experimental design- measurements are not always reliable => to replicate- the marble is not heavy enough and speeds are too small => to try with a
lead ball on higher falling heights
Limitations of the simulation- we did not take into account the atmosphere!!! (friction, fragmentation...)- we did not consider the fact that a part of the energy of the asteroid is not
used for the cratering process (melting of rocks...)
French National Conference
French National Conference
Aknowledgments
To all our classmates: Thomas ABDEDOU, Adel ARIOUI, Mohamed BAKKALI, Soleyman BELAFEKIR, Ilhem
BENHARRAT, Chaïma BEN YAHIA, Amandine BILLON, Ninon BLANCHARD, Wassil BOUGUELMOUNA, Soummaya BOUTARA, Sonia BOUZERD, Océane CLOSSET, Jade DAURIAT, Binta DIALLO, Soumia FARTAS, Evren GUNGOR, Anissa HASSI, Pascal HUYNH, Zeineb JERIBI, Horlin KOPA, Hoang-Yen LAM, Fabien ONNIS, Julie PIGA, Amina SAMSAR, Dylan SIMOES, Bilel SOUFI, Katya YAHAOUI, Sarah ZAHOTE, Ange ZONGO
To our teachers: Ms CHENEY, Mr. ARNAUD and Mr. LANDRY
To CIFOP and the european program Chain Reaction
which enabled us to share our work with you
Thank you foryour attention :-)))
GOSCINNY and UDERZO, Asterix