Today they are a reality, so now we have an important sign of the end time according to the Bible. Sadly, the scientific progress has been accompanied by moral and spiritual decline. More people have been slaughtered in the twentieth century than the whole of the world population in the first century. Science has given us the weapons of mass destruction, and now even China is a nuclear power. Even people who regard themselves as well educated are abysmally ignorant of the Bible.
Scientific advance coupled with moral and spiritual decline is deadly.
It puts more power into the hands of evil men, who are drifting further and further away from God. This had to be before the coming of the Lord to fulfil prophecy. For I will gather all nations against Jerusalem to battle. This is Armageddon, and the rapture of the Church will take place seven years before this event. This period is known as the Great Tribulation.