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