at the beginning of the 20th century, swedish astronomer knut emil lundmark thought that there was aes. but only towards the end of the 20th century astrophysicists confirmed it. that the nebula appeared precisely from the explosion of a chinese supernova, the diameter of the nebula itself is 11 light years, it is constantly expanding by about 1,500 km/second. 4 on july 1903, us president theodore roosevelt solemnly announced the opening of the pacific line of communication, sending messages throughout the world via a cable laid along the bottom of the pacific ocean. cables had already been laid in europe, one in india, then still a british colony. at the beginning of the 20th century, britain was a leader in this matter. around the world, 30 ships were engaged in laying the cable, and 24 of them belonged to british companies. now 120 years later, 99% of data is transmitted from country to country, from continent to continent, through cables at the bottom of the seas of the oceans. they entangle the entire planet except antarctica. some of them are for military purposes; information