Spanish MODIS Astronomers observe record-breaking lunar impact in Mare Nubium

An image of the flash resulting from the impact of a large meteorite on the lunar surface on 11 September 2013, obtained with the ESO MIDAS observatory. 

Credit: J. Madiedo / MIDAS

A meteorite with the mass of a small car crashed into the Moon last September, according to Spanish astronomers.

The impact, the biggest seen to date, produced a bright flash and would have been easy to spot from the Earth.

The scientists publish their description of the event in the journal Monthly Notices of the Royal Astronomical Society.

The Moon lacks the atmosphere that prevents small rocks from space from reaching the surface of the Earth.

The result is very visible – vast numbers of craters large and small cover the whole of our nearest neighbour and record 4.5 billion years of collisions that span the history of the Solar system.

Although there is almost no chance of a very large object striking the Moon or planets, collisions with smaller objects are very common even today.

The odds of seeing one of these by chance are pretty poor, so scientists have set up networks of telescopes that can detect them automatically.

Jose M. Madiedo

On 11 September 2013, Prof Jose M. Madiedo was operating two telescopes in the south of Spain that were searching for these impact events.

At 2007 GMT he witnessed an unusually long and bright flash in Mare Nubium, an ancient lava-filled basin with a darker appearance than its surroundings.

The flash was the result of a rock crashing into the lunar surface and was briefly almost as bright as the familiar Pole Star, meaning that anyone on Earth who was lucky enough to be looking at the Moon at that moment would have been able to see it.

In the video recording made by Prof Madiedo, an afterglow remained visible for a further eight seconds.



The October event is the longest and brightest confirmed impact flash ever observed on the Moon. Prof Madiedo recalls how impressed he was: "At that moment I realised that I had seen a very rare and extraordinary event."

The Spanish telescopes are part of the Moon Impacts Detection and Analysis System (MIDAS) system that monitors the lunar surface.

Jose L. Ortiz

This project is being undertaken by Prof Jose Maria Madiedo, from the University of Huelva (UHU), and by Dr Jose L. Ortiz, from the Institute of Astrophysics of Andalusia (IAA-CSIC) and continues a pioneering program that detected sporadic lunar impact flashes for the first time.

Since these impacts take place at huge speeds, the rocks become molten and are vapourised at the impact site instantaneously, and this produces a thermal glow that can be detected from our planet as short-duration flashes through telescopes.

Generally, these flashes last just a fraction of a second but the flash detected on 11 September was much more intense and longer than anything observed before.

More Information: “A large lunar impact blast on 2013 September 11”, José M. Madiedo, José L. Ortiz, Nicolás Morales and Jesús Cabrera-Caño, Monthly Notices of the Royal Astronomical Society, Oxford University Press, in press. A copy of the paper is available from mnras.oxfordjournals.org