Monday, September 22, 2014

UFOs in Portsmouth?

I'm quoted in the Portsmouth News and the Daily Mail this week commenting on a UFO (unidentified flying object) seen in Portsmouth. I sent my comments in an email to Portsmouth News reporter. What was printed in the story was this: 

' Given that the pictures show a dark object against a daytime sky it's clearly not an astronomical object. Many "UFO sightings" are actually the planet Venus, but this one can't be that.  
The distances in space are so vast that it's just not possible for aliens to be visiting Earth, so any interpretation suggesting this is an alien spacecraft is clearly wrong. '

So what were these statements based on? Here's some more extended explanation I sent to the reporter about the vastness of space: 

The nearest star is more than 3 light years away - meaning it would take more than 3 years to make the trip even at the speed of light. Most stars which are visible in the night sky are within about 1000 light years of Earth. That's considered close on astronomical scales, and that's a distance which takes 1000 years to travel even at the speed of light. 

 Most people don't understand just how fast the speed of light is. If they look at the length of one of their arms, light travels that length in 1 nano second (1 billionth of a second). It travels the distance between the Earth and the Moon (which took the Apollo astronauts 3 days to cover) in just over 1 second, and reaches the outer edge of our Solar System in about 5 hours (a spacecraft has been on its way there from Earth since 2006 and is only just arriving). 

 Light travels at about 10 million times faster than the typical speed a jumbo jet. 

 In order to make a spacecraft travel even close to the speed of light would take vast quantities of energy - many many many times more than any energy source we are aware of (including carrying entire stars along with you to power your spacecraft). 

Supposing you could accelerate your spacecraft fast enough - then any collision between such an object and even a microscopic piece speck of rock in space would cause it to explode. 

 Physics really tells us that interstellar travel is just not possible, despite how much fun the stories and films about it are. 

Here's the picture of the #pompeyufo people were sharing online. I still think it looks like a cloud based on this picture! 
People might (and do) object to these statements about it not being physically possible for aliens to visit Earth. In Science Fiction new physics is invented to get around the problems. The most famous example is warp drive (e.g. in Star Trek) which gets around this by warping space time so that the distance between two places is made much smaller. My problem with invoking this is that we might as well then invoke magic. We can imagine ways to bend our current knowledge of physics to get around the speed limit of light, but it doesn't mean it's actually going to be possible. The energy source is I think the biggest stumbling block - it's not like we just need to find something with a bit more energy than rocket fuel, it's something with billions and billions of times more energy, and which doesn't immediately disintegrate us at the same time! 

 If you are keen on aliens, the positive news about the size of the Universe is that there are so many stars in the Universe I find it implausible to believe we're the only life in it, but the sad thing is that the distances between stars, let alone between galaxies are so vast, that I also find it implausible to believe that any civilisation would/will ever be able to work out a way to travel between them. 

And if they did I think the last thing they would do is to buzz Portsmouth, UK and then disappear without trace. 

I still think it's a cloud. 

Update 24th Sept: I was wrong about it being a cloud - the whole thing was faked as a publicity stunt for a SciFi event happening this weekend in Portsmouth.