Alien space ship or comet?

Astronomers are set to scan an 'alien' comet for signs of extraterrestrial technology.
The cigar-shaped asteroid, named 'Oumuamua by its discoverers, sailed past Earth last month and is the first interstellar object seen in the solar system.
A team of alien-hunting scientists, led by Russian billionaire Yuri Milner, will scan the comet this week before it sails beyond the reach of Earth's telescopes.
They say they are looking for radio signals, claiming the mysterious visitor could be an alien spaceship.
The alien-hunting project will use the Green Bank Telescope in West Virginia for its investigation, with the campaign set to begin at 3:00pm ET (8:00pm GMT) on Wednesday.
The telescopes sensitive equipment would would take less than a minute to pick up something as faint as the radio waves from a smartphone, according to the Atlantic.
Milner, the business mogul behind Breakthrough Listen, a $100 million (£75m) search for intelligent extraterrestrial life, received an email about the object last week from one of his chief scientists.
'The more I study this object, the more unusual it appears, making me wonder whether it might be an artificially made probe which was sent by an alien civilisation,' Professor Avi Loeb, the chair of Harvard's astronomy department and one of Milner's advisers on Breakthrough Listen, wrote in the email.
Professor Loeb said the space rock's peculiar elongated shape is odd for a common space rock but ideal for a ship flying between star systems.
Breakthrough Listen has now announced the program will scan 'Oumuamua this week for signs of radio signals.