Did the Moon move for you?
It wasn't Hollywood; it wasn't Bruce Willis. But I don't really think anyone truly expected that it would be.
to see if it could kick up sufficient debris that it might be able to detect the presence of water.
It has long been suspected that some of the craters in the Moon's polar regions might hide ice in their permanently shadowed regions - ice that was delivered billions of years ago by comets or water-rich asteroids.
We all looked intently at the images fed back to Earth by a closely trailing spacecraft, LCROSS (the Lunar Crater Observation and Sensing Satellite).
We were told to look for a sort of shimmering in the pictures.
Our armchair view of events switched between a visible camera and an infrared one.
I didn't see anything in the images; those around me didn't see anything either.
We weren't the only ones. One Twitter feed I checked belonged to colleague Dr Chris Lintott, the co-presenter of the 91Èȱ¬'s long-running astronomy programme, The Sky At Night.
Chris was following everything in California at the Palomar Observatory, which has a 200-inch telescope. : "No plume visible from Palomar".
The good news, according to Nasa, is that LCROSS did manage to detect the impact, and the spectrometers onboard have returned important data.
The impact was set up to make the biggest debris field possible. The 2.2-tonne rocket upper-stage went into the Moon at 2.5km/s at an angle of 80 degrees.
The target - the Cabeus Crater - was chosen because lighting conditions would be ideal to illuminate the ejected dirt and rock, some of which was expected to lift 10km above the crater floor (Cabeus is 100km wide and 3-4km deep).
There is a huge mountain that sits on the rim of Cabeus, but light streaming down a valley towards the crater should have made for excellent observing conditions.
Nasa will take its time to update us on the results. Don't expect immediate and definitive statements about success or failure. So many telescopes - both professional and amateur - were trained on this event that it will take some time to produce a full assessment.
All Nasa will say for now is that is has the data it needs to do the analysis.
But what if it gets a minimal or zero signal for water in any ejected plume? What does that mean?
If the signal is very low, it has "resource implications". Remember, this mission was part of the robotic preparation to return astronauts to the Moon.
A series of unmanned probes will map the lunar surface in the coming years, to find the best landing sites for humans.
If water-ice exists at the poles in shadowed craters, it could be useful - to drink and to make rocket fuel. It could help sustain a long-term base of the kind envisaged by President George Bush when he set Nasa on a new course of exploration in 2004.
And with every kilo of payload costing something in excess of $20,000 to launch to the Moon, any item which can be "purchased" locally would be a huge advantage.
But if there really is little in the way of water, it may put a big question mark against the idea of bases. We've seen already from the Augustine committee set up by President Obama to review the Bush plans that thinking in the US may already be shifting to the idea of a few, shorter visits, and not extended stays.
It could be, of course, that the rocket just hits a dry hole; it could be that plenty of water-ice is buried on the Moon but that it's not very evenly distributed. However, this would seem unlikely.
Another reason Cabeus was chosen was because it was shown by a previous mission to be an excellent candidate.
The Lunar Prospector spacecraft which finished its mission in 1999 found a strong signal for hydrogen at the crater. Hydrogen by itself is not proof of the presence of water, but most think of it as a reasonable proxy.
Over to you, Nasa.
±õ’m 
Comments
or to comment.