Timing is the real problem in all this, bigger than the distances involved, IMO.
The odds of at least one other civilisation at a similar level of development as we are, existing at the same time as us, with the same curiosity to ask the same questions and reach out to look for the signs of life elsewhere is just so mind bogglingly small that to all intents and purposes, we may as well be alone.
Not really. Especially when you consider how huge our galaxy is.
There have been various attempts to calculate this, but the estimate are that there are between 300 million and 40 billion Earth like planets in the Milky Way. A commonly cited mid-range figure is roughly 1 in 5 Sun-like stars having an Earth sized planet in its habitable zone. However, that doesn't mean that they're actually habitable for life, but we could be looking at a minimum of millions of planets with life just in our galaxy.
The chances of advanced civilisations would be very rare, but not so impossible to the extent that we might as well be alone.
That's just the milky way. At a universal level it gets even more unlikely. There are an estimated 2 trillion galaxies in the observable universe. If each has a similar count to the Milky Way, we are looking at a number of habital planets in the sextillions.
I haven't even included moons. There is a very good chance other life on moons in our system, such as Europa for example. If life can also form on moons then we're getting into inconceivable numbers of possible places for life in the universe.
for us to be the only technological civilization to have ever existed in the universe would have to be less than 1 in 10 billion trillion.
That's not to say that we're currently being visited by aliens. Just that the chances of us being alone or the only intelligent civilisation is practically zero.
He's probably trolling. He says they're real and adds no explanation on how he knows this. But it would make sense not to tell the POTUS this information.
The POTUS is a temporary position and wouldn't need to know.