Thousands of people witnessed the fireball and hundreds of them called the Instituto de Astrofísica de Canarias. The details given below are a brief summary of the comments made by the many people who called with information and also on a number of interviews of key witnesses.

    Around 22:30 local time (21:30TU) radio transmitters on the island of Tenerife began to interrupt their normal programmes to put out on the air the calls from listeners who had witnessed, astonished, a few minutes earlier, a huge light in the sky. Some people commented that it appeared to have been a meteor, although much brighter than any that they had ever previously seen. Later, many people who witnessed the even called the Instituto de Astrofísica de Canarias to report their observations and impressions, or to ask for information about the event. In the last category the Civil Governor of the Province of Santa Cruz de Tenerife and the Air Force base at Gando (Gran Canaria). Thanks to a considerable effort from the IAC Press Office it was possible to send out an initial report on the events and their explanation at 11:30 on Monday morning; this was submitted to the Civil Governor, to the military command and the information services of the islands.

    In the first few minutes after the event, various hypotheses were advanced, apart from a meteor. Some people compared the object to an aircraft crashing in flames, although this could be rejected quickly as neither the Air Force, nor the Civil Defence Authority, nor the Spanish Civil Aviation Authority had news of an accident in the Canary Islands region. In the same way, Air Traffic Control in the Canaries had not detected the object by radar.

    According to the many witnesses, the event happened just after ten in the evening. Being a Sunday and having had very fine weather, the early evening hour meant that many people were out and about, often returning home after a day out. This contributed to the very large number of witnesses. One person who called the IAC fixed the time that the fireball appeared, very exactly, as 22:08 because she had checked the clock carefully. Other callers gave the time as 22:15 or, even, later. Families travelling on the southern motorway after a day on the beach enjoying the wonderful prevalent in the islands saw how the object which, initially, looked like a normal meteor, became ever brighter as it crossed the sky, instead of simply disappearing quickly.

    Many callers and witnesses commented that the meteor looked like a comet with a long tail and was strongly coloured. Peter Hammersley, a scientist at the IAC, was walking down to the bus stop outside the building and saw the fireball very clearly. He commented that it had a very strong green colour and set behind a mountain to the north-north-east of the city of La Laguna. The fireball appeared to the left of the neighbouring island of Gran Canaria (implying that it was almost exactly to the east of La Laguna) at a height of about 45 degrees above the horizon. Giving further details he says that the fireball appeared 5 degrees West of Arcturus, passed a few degrees below the star and moved down towards the north before setting behind the peaks of the mountains on the outskirts of La Laguna.

    The bolide was about as bright as the moon, implying a magnitude around -12 or -13. Another witness suggested that the magnitude reached -17, in which case it would have been one of the brightest fireballs of recent years; this report though appears not to be due to a direct observation and cannot thus be given as valid. An excellent proof that the magnitude was fainter than this is given by the fact that a search for the track of the fireball in the archive of Earth reconnaissance satellites has not revealed it to have been registered. These satellites are capable of registering a -18 fireball by day and, by night, can reach several magnitudes fainter.

    Carlos Westerndorp, another IAC scientist, saw the bolide disappear to the north as seen from the town of Puerto de la Cruz, on the north coast of the island of Tenerife. Eva Redondo, also observing from Puerto de la Cruz, saw how the meteor ended at an estimated altitude of 10 degrees above the sea horizon. Other witnesses, for example drivers on the southern motorway on Tenerife, or the inhabitants of villages in the south of the island, saw how the fireball set behind the mountains to the north.

    The most restricting of the reports of the altitude above the horizon where the trail ended is, again, from Peter Hammersley. From his vantage point the trail was clearly seen to go behind mountains before the terminal explosion. Given this physical reference it is possible to state that the altitude was probably some 8 degrees (greater than 5 degrees, but less than 10).

    Very similar reports have come from witnesses on the neighbouring island of La Palma, 150km West of Tenerife. A woman in the outskirts of Santa Cruz de la Palma (to the West of the island) described, in a way virtually identical to many people on Tenerife, how the fireball latest around 5 seconds, or a little longer, before setting behind the mountains of the island. Many observers also noted that the object left a bright train, although appears to have been of brief duration. The fireball was also seen from the eastern islands of Gran Canaria y Lanzarote. All of these reports speak of the fireball in the same way. From Lanzarote airport the fireball appeared towards the neighbouring island of Fuerteventura, to the south-west as seen from the control tower. 

    Various witnesses in Gran Canaria commented that a second fireball of magnitude -7 appeared a few minutes later, although this cannot be related to the first fireball as the physical separation of the two was around 20 thousand kilometres.

    Some people were seriously alarmed by the fireball. One witness who was in a car on the southern motorway of the island of Tenerife described how she took cover expecting that a very loud explosion would follow. Although some witnesses did not report any unusual noise, others reported, very consistently, that they had heard a dull rumble in the distance. Danielle Dalloz, an amateur astronomer and meteor observer reported that she had not seen the fireball, but that she had heard a noise similar to the movement of the curtains in her flat in Santa Cruz (Tenerife). However, it seems that the noise cannot have been very great given that many people did fail to hear it.

    Although many people appear to have seen the bolide directly, many more saw it only indirectly. immediately after the disappearance of the meteor a very bright flash of light was seen. This flash was so strong that many people saw it from inside their houses though curtains, or even blinds. A typical report of this kind was that made by the Ramos family from the village of Tegueste, in the north of the island of Tenerife. From Teide Observatory the fireball was not observed directly, but Alejando González observed saw how the sky suddenly brightened and Mount Teide was lit up. Peter Hammersley notes that the light was so bright that the mountains outside La Laguna were lit up and the sky went white with the flash. Many witnesses are unanimous about these details despite having observed from different points of the various islands.

    Initial reports did not speak of the fragmentation of the object and some confusion and conflicting reports were made later. There seems no doubt though that the fireball seen crossing the sky had two nuclei, a fact clearly stated in reports from Tenerife and Gran Canaria. Various witnesses also reported how sparks flew off behind the bolide as it crossed the sky, although it does not appear that there are any reliable reports that would suggest that the object fragmented completely before exploding.

    Despite the fact that, given that the region is mostly water, it is not probable that the object fell on land, there have been a number of reports of falls. This is, without doubt, the biggest point of discrepancy between witnesses. After a report of an observed fall the Civil Guard searched the region of Taganana (on the north-eastern tip of Tenerife). Two fishermen out in a boat saw the fall of the object, in this case in the sea very close to the north-western tip of the island, close to the village of Garachico. They were unable to estimate the distance of the fall from their boat but felt that it was not more than 1Km as it passed between their boat and a mountain on the coast. From La Palma, it was reported that the object had appeared to fall in the north of the island. Fishermen in Gran Canaria put out to sea thing that the fireball was a flare from a boat in distress. Other reports were made from the island that "a piece fell 300m from the coast" and that "a fragment fell in the region of Bañaderos".

    Thanks to the large number of reports the path of the fireball can be calculated with a reasonable degree of accuracy. Unfortunately though, the lack of precise positions from the easternmost islands means that an exact two station triangulation is impossible and the starting and finishing heights in the atmosphere can only be estimated. In both cases there are extensive studies of the behaviour of meteors and fireballs that allows some reasonable guesses to be made.

    The track probably began at about 120Km height, above the Atlantic, to the north-east of the city of Las Palmas, almost exactly half way between Santa Cruz de Tenerife and Puerto del Rosario (Fuerteventura). This start point is well determined and its error is probably no greater than about 10Km. The fireball then travelled some 180Km over the ocean, in a north westerly direction, ending at a height which was probably around 20Km (an extensive study of Spacewatch asteroids suggests that the height for fragmentation is, according to the composition, from 10-30Km, with the more common stony meteorites fragmenting at around 20Km altitude), 130Km to the north of Tenerife. This termination point has a larger error than the start point, but is probably good to no worse than 25Km. The path at no point passed over solid land and, even allowing for the largest possible errors in its calculation, it is impossible that a fragment could have landed on, or even close to one of the islands. In fact, any surviving fragments of the meteorite are probably located on the ocean floor, at more than 3000m depth.

    The fireball came down at an angle of 35 degrees below the horizontal. Given the geometry and the estimates of the duration of visibility, the initial velocity in the atmosphere was probably in the region of 50-60Km/s, assuming that it was almost completely braked before exploding.

    Without having pieces of meteorite, it is impossible to talk about the type of object that gave rise to the fireball, although it is tacitly assumed to have been a stony meteor from the observed characteristics. Although the Eta Aquarids were at maximum on the night of observation of the fireball it can be shown that this was not a fragment of Comet Halley! As seen from the Canary Islands the radiant of the Eta Aquarids rose 5 hours after the fireball was seen and the observed path is totally incompatible with the Eta Aquarid radiant. In fact, the radiant was towards Hydra or Antila.

    One curious detail was the sound from the bolide. The track was never less than 50Km from land and usually more than 100Km, thus it is physically impossible to have heard it less than 1-2 minutes after the fireball. The reports though indicate that there was little, if any delay. This may be yet another case of an inexplicably noisy meteor, to add to the many unexplained (and unexplainable) reports made over the years.

    The May 7th fireball appears to have been due to a half Kilogram (approximately) meteorite which passed over the Atlantic Ocean, starting at a point between the islands of Gran Canaria and Fuerteventura, and travelling north-west, to explode (and presumably fall) around 120Km to the north of Tenerife. Any surviving fragment fell in the ocean and is on the ocean floor at a depth of greater than 3000m.

    Far more people called the IAC than could be handled by a single person. Carmen del Puerto and Begoña López of the IAC Press Office did an impressive job of separating out the calls which had particularly useful information. Luis Bellot contacted and interviewed various of the eyewitnesses and Javier Méndez gave the initial alert on hearing the first radio reports. Peter Hammersley and Carlos Westerndorp, IAC astrophysicists, and highly important witnesses, are especially to be thanked for their clear and accurate reports, as well as their patience with an endless stream of questions about their observations.

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