2009 ND DD45

Asteroiden som passerade jorden på 72000 kilometers avstånd häromdagen (som rör sig från vänster till höger i videon ovanför) gav i den här CBC-artikeln upphov till en av de sakligaste och informativa läsarkommentarer jag stött på på ett bra tag i de ofta så arga och rättshaveristiska kommentarsfälten. Kommentaren i dess helhet från en medlem i The Royal Astronomical Society of Canada:

To those who are wondering / complaining about the fact that the announcement came only after this object had passed, and that there was little or no warning:

1. A tiny rock this size is so faint that it is virtually impossible to see, even in the largest telescopes, until it is very close to Earth (remember what you learned in grade school? The brightness of an object decreases with the square of the distance).

2. As soon as the object was spotted, it was reported, and there was a lot of publicity in the astronomical community. For the last 48 hours or so - many hours before it passed by - members of an astronomical chat line to which I belong have been discussing this object, its precise location and trajectory, etc. There was certainly no attempt to cover this up or to delay announcing it. Stuff like this actually happens quite often, and news agencies sometimes think that only astronomical geeks such as moi are interested.

BTW, there have been detailed studies about the size of waves that would be produced by asteroids/meteoroids of various sizes hitting an ocean. Unless the object is on the order of a kilometre or so in diameter and strikes in a shallow area, the waves that would be generated would initially be higher than even the largest tsunamis, but they would VERY quickly peter out, because the water displacement would be surface only. A tsunami (Japanese for "harbour wave") travels great distances and rears up when it reaches shore because it is caused by an ocean floor disturbance, which displaces the ENTIRE water column above it to the surface. That doesn't happen with a small asteroid meteoroid.