Craters

Final Astronomy Lab

Lunar Crater Categorization

• In 1978, Chuck Wood and Leif Andersson of the Lunar & Planetary Lab devised a system of categorization of lunar impact craters. They used a sampling of craters that were relatively unmodified by subsequent impacts, then grouped the results into five broad categories. These successfully accounted for about 99% of all lunar impact craters.

http://www.unm.edu/~abqtom/images/Moon/Moon11-19-02b.jpg

The LPC Crater Types:

• ALC — small, cup-shaped craters with a diameter of about 10 km or less, and no central floor. The archetype for this category is 'Albategnius C'.

http://www.edwardroach.com/uploads/Albategnius_9-3-07_504edt_300frames.jpg

The LPC Crater Types:

• BIO — similar to an ALC, but with small, flat floors. Typical diameter is about 15 km. The lunar crater archetype is Biot.

http://www.astrospider.com/images/moon/Biot_LAC98map.jpg

The LPC Crater Types:

• SOS — the interior floor is wide and flat, with no central peak. The inner walls are not terraced. The diameter is normally in the range of 15-25 km. The archetype is Sosigenes crater.

http://history.nasa.gov/ap15fj/photos/o/as15-97-13288.jpg

The LPC Crater Types:

• TRI — these complex craters are large enough so that their inner walls have slumped to the floor. They can range in size from 15-50 km in diameter. The archetype crater is Triesnecker.

http://www.damianpeach.com/lunartemp/triesnecker02.jpg

The LPC Crater Types:

• TYC — these are larger than 50 km, with terraced inner walls and relatively flat floors. They frequently have large central peak formations. Tycho crater is the archetype for this class.

http://upload.wikimedia.org/wikipedia/commons/7/7e/Mooncrater.jpg

The LPC Crater Types:

• Beyond a couple of hundred kilometers diameter, the central peak of the TYC class disappear and they are classed as basins.

http://www.uwsp.edu/geo/projects/geoweb/participants/dutch/Sudbury/schrodinger.gif

Question

• How do the variables of velocity, size, and meteor angle to surface affect the outcome of resultant craters?

http://apod.nasa.gov/apod/image/0507/impact13sec_deepimpact_hri.jpg

Hypothesis

• Develop a hypothesis about the outcome of your experiment based on your observations, reading, and experience

http://www.photoaxe.com/wp-content/uploads/2007/02/droplet.jpg

Your Lab

• You collected data on:– Speed of the impact

(depending on height you dropped your clay ball)

– Angle of impact (depending on how far back you were)

– Size of meteor (depending on whether your clay was 1, 2 or 3 pieces)

http://upload.wikimedia.org/wikipedia/en/c/c8/AS11-42-6285.jpg

Finish Collecting Data

• Collect your data• Return all your

equipment• If you have finished

your collection, you may spend time with the resources

http://crism.jhuapl.edu/education/downloads/GUIDE_Lesson2.pdf

Analyze Your Data

• You collected 3 trials of a single variable, then collected 3 trials of the next variable, and so on.

• Find the mean of each of your variables.– Add three trials and

then divide by 3

1.2 1.3 1.1 3.6 1.2

0.8 1.0 0.9 2.8 0.9

3.0 2.4 3.1 8.5 2.83

1.9 2.3 1.7 5.9 1.96

1.8 1.7 2.1 5.7 1.9

4.2 4.1 4.8 13.1 4.36

3.2 3.8 3.9 10.9 3.63

2.3 2.8 2.8 7.9 2.33

5.2 5.2 8.2 18.6 6.2

4.5 4.3 4.1 12.8 4.26

3.4 3.1 3.1 9.6 3.2

6.0 5.8 6.2 18.0 6.0

Analyze Your Data

• First, let’s look at how our data varies around the mean

Variation

0.0

2.0

4.0

6.0

8.0

10.0

1 2 3 4 5 6 7 8 9 10 11 12

Trials

Cen

tim

eter

s

Dropped at 30cm Trial 1 Trial 2 Trial 3 Total Average

Diameter 1.2 1.3 1.1 3.6 1.2Depth 0.8 1.0 0.9 2.7 0.9Rays 3.0 2.4 3.1 8.5 2.8Dropped at 60cm

Diameter 1.9 2.3 1.7 5.9 2.0Depth 1.8 1.7 2.1 5.6 1.9Rays 4.2 4.1 4.8 13.1 4.4Dropped at 90cm

Diameter 3.2 3.8 3.9 10.9 3.6Depth 2.3 2.8 2.8 7.9 2.6Rays 5.2 5.2 8.2 18.6 6.2Dropped at ~2m

Diameter 4.5 4.3 4.1 12.9 4.3Depth 3.4 3.1 3.1 9.6 3.2Rays 6.0 5.8 6.2 18.0 6.0

Analyze Your DataImpact Crater

0.0

5.0

10.0

15.0

20.0

25.0

Variables

Ce

nti

me

ters

Rays

Depth

Diameter

Rays 1.2 0.9 2.8 2.0 1.9 4.4 3.6 2.6 6.2 4.3 3.2 6.0

Depth 1.1 0.8 2.4 1.7 1.7 4.1 3.2 2.3 5.2 4.1 3.1 5.8

Diameter 1.3 1.0 3.1 2.3 2.1 4.8 3.9 2.8 8.2 4.5 3.4 6.2

30 cm

60 cm

90 cm

~2m

• Next, let’s start picturing our data using averages– Does this make sense?

Analyze Your Data

• How about this graph?

Impact Craters - Velocity

1.0 2.0 3.0 4.0 5.0 6.0Diameter

0.5

1.5

2.5

3.5

Dep

th

2m90cm60cm30cm

Height Above Surface

Analyze Your Data

• Or this one.

Impact Crater - Velocity

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Height Dropped

Cen

tim

eter

s

Diameter

Depth

Rays

Diameter 1.2 2.0 3.6 4.3

Depth 0.9 1.9 2.6 3.2

Rays 2.8 4.4 6.2 6.0

30 cm 60 cm 90 cm ~2m

Conclusions

• What is your answer about the size, depth and ray length as the velocity increases?

• If you have any unusual data, give an education guess what happened (most likely, human error)

Impact Craters - Velocity

2m90cm60cm30cm

Height Above Surface

For This Lab…

• Produce an 8½ x 11” or larger “poster” of this experiment

• Introduction: Background on craters (tell me how they are formed)

• List your citations

• Methods: Describe your experimental design (include your hypothesis)

• Results: Include both a table and graph of your data

• Discussion: Tell me what you learned

Be Creative

Have Fun

What Did You Learn

Include 4 Sections