Comments on Professor Astronomy's Astronomy Blog: Did NASA's Moon impact Fail?

If our beloved country could do thid it would do i...

2009-10-12T11:20:14.458-05:00

If our beloved country could do thid it would do it in a way that everyone in the world could see it. It would boost respect, it would boost the economy, it would tell the world we are "leading" in science... But like the moon landing, all this seems to be just a political stunt to create the illusion that we can make it. In my opinion; it never happened, not the moon landing, not this.

I knew that they shouldn't have used disposable ca...

2009-10-10T20:06:52.441-05:00

I knew that they shouldn't have used disposable cameras!

Although the impact is high energy, the moon is bi...

2009-10-10T17:55:52.198-05:00

Although the impact is high energy, the moon is big and a quarter million miles away. The crater where the impact occured (in the picture above)is 60 miles in diameter, at least a couple of miles deep, and permanently shadowed. The LCROSS impact inside this crater therefore needed to loft debris at least a mile or two into the air to get it into the sunshine. The impact was probably sufficient to do that. But suppose the debris cloud was a couple miles high and a couple of miles across. That would be 1/30 of the diameter of the crater in the picture above -- relatively small as seen from Earth.

NASA's hope was that the impact would release a lot of water. That water would instantly freeze in the vacuum of space and reflect a lot of light back toward Earth. That should have been visible, despite the small size.

However, if the plume was mostly lunar dust, the plume would be no brighter than the Moon's surface (which is as black as asphalt). Trying to pick out a small black cloud of dust against a background of black rock is extraordinarily difficult. And my guess (and that's all it is) is that the plume was mostly lunar dust, with little if any water. From a quarter million miles away, it's just not going to be visible without careful image processing.

We know the Centaur rocket stage hit, because LCROSS saw a flash in infrared light (http://antwrp.gsfc.nasa.gov/apod/ap091010.html), and we know LCROSS hit the Moon because all of its transmissions ceased right at the predicted instant of impact.

Any way you slice it, any reasonable person would ...

2009-10-10T11:43:40.598-05:00

Any way you slice it, any reasonable person would expect a 2-ton projectile hitting the surface of the moon at 5,000 mph to cause a visually observable impact. There was NOTHING! It is no wonder the public was so skeptical. This was a super high-energy impact. The most basic thing that NASA could assume was that this would create a huge plume of dust and debris. That did not happen at all. What happened, then?