Posts Tagged ‘67P’


The Rosetta Project scaled down to a Lego Universe

November 28, 2014

According to Warwick Holmes, ESA:

The images were taken by the OSIRIS-Narrow-Angle-Camera on-board Rosetta spacecraft orbiting 15.5km above the surface of Comet-67P. They show the Philae trajectory before and after the first touchdown, which occurred at 15:34 GMT (12 Nov).  As previously reported the harpoons did not fire into the comet to hold Philae down.

The small inserted images show the imprint of the three Philae foot-pads left in the dusty surface of the comet (compare “before” 15:23 image and the “after” images at 15:43)  Philae first touchdown was at 15:34 GMT.

1 OSIRIS_spots_Philae_drifting_across_the_comet  2
Philae bounced off the comet surface after the first touchdown and remained “airborne” for 1hr 50min.  The first bounce was 1km high and went 1km directly east on this image.

Philae then touched down a second time resulting in a much smaller second bounce which lasted only 7 minutes.  The gravitational force on the surface of Comet-67P is 1/50,000th of (“g”) Earth’s gravity, hence the very high and long re-bounds.

This image does not show the second or final third touchdown positions as they were outside the field of view of this image as Philae continued heading east with respect to this image.
1a Rosetta lander on comet

Finally, Philae completed 100% of the science data acquisition sequence that was planned on the surface despite the “rough” landing(s).  It will probably be several months before exact scientific findings are being published as the scientists shall be spending many weeks processing and examining the plethora of scientific data from Philae and Rosetta over the landing site.

 This is fabulous. Live Comet up date here

To appreciate the distances involved we will scale everything down to the

Lego Universe:

2 Lego Space Cadet Human Ratio Mathspig

3 Lego Scale philae and comet

4 Lego Universe 1 mathspig

5 Lego Universe 2  Mathspig More Rosetta data from Warwick Holmes, ESA.

6 Rosetta Data


The Rosetta Project … like throwing a dart from Sydney to Perth and hitting the bullseye

November 28, 2014

Many commentators in Australia claimed that the Philae landing was:

This is equivalent to hitting the bullseye of a dartboard in Perth from Sydney. With a billion euro ($1.4bn) dart. While blindfolded (as the mission was powered down for almost the entire journey). ABC The Drum

Did they get the maths right?

Inner bullseye of dartboard = 12.7 mm

1 Dartboard

67P comet = 4.1 km = 4,100 m at widest point

Distance comet from earth = 520 million km

 Actually, hitting the 67P comment was more like roulette as the Rosetta mothership swung into orbit. And, as the earth and the comet are moving, the distance constantly changes, but you can watch the distance changing here.

Fabulous Graphics from the Daily Telegraph

Fabulous Graphics from the Daily Telegraph

In the Dart Throwers Universe

We will assume someone can stand on earth and throw a dart at the comet … Yes! They would need very big triceps.

3  Dart throwers universe correction


So the commentators aren’t even close. It would still be a feat hitting a bullseye with a dart from 160km, but that would be from Sydney to, um, Nowra on the coast. 


Comet vs bullseye ratio mathspig

Mt Everest RAtio

4 Dart Throwers universe 3

The distance from Sydney to Perth is 4100 km. At best the commentators would be talking about throwing a dart from Brisbane to Adelaide is 2044km (below).

Brisbane to Adealide