A reader left a post on our Your Questions section about a string of lights crossing the night's sky. We looked up the answer.

Has anybody seen the lights in the sky tonight 7 May at about 10.45 travelling west to east? There must have been about 50 of them making no noise & equally apart & all disappeared at the same point… very eerie.

Jim Cooknell

Hi, Jim.

There were lots of people who witnessed the same as you, both on the night of the 7th and on the 8th and there is an explanation that has more to do with satellites than UFOs (you didn’t suggest the latter, but some people did).

On the night of the 7th between 22.30h and 23.00h a whole string of lights moved across the sky, in a straight-line formation and in silence, clearly visible to the naked eye.

The astrophysist, José María Madiedo, who belongs to the Instituto de Astrofísica de Andalucía (IAA-CSIC) supplied the explanation: The culprits were 60 Starlink satellites which had been released by a SpaceX rocket on the 4th of May.

The night following the release of the satellites they were visible because they had still not reached their orbit height but were crossing the sky a few hundred kilometres up.

To quote from Wikipedia on Elon Musk’s Skylink project: Starlink is a satellite internet constellation being constructed by SpaceX, providing satellite Internet access. The constellation will consist of thousands of mass-produced small satellites in low Earth orbit (LEO), which communicate with designated ground transceivers.

• First shell: 1,440 in a 550 km (340 mi) altitude shell at 53.0° inclination
• Second shell: 1,440 in a 540 km (340 mi) shell at 53.2° inclination
• Third shell: 720 in a 570 km (350 mi) shell at 70° inclination
• Fourth shell: 336 in a 560 km (350 mi) shell at 97.6°
• Fifth shell: 172 satellites in a 560 km (350 mi) shell at 97.6°

(News: Andalucia)