The landing on Altair 4 from the film ‘Forbidden Planet’. PHOTO/GETTY IMAGES
NICK SAULT – SKY WATCH
The bright planets are really hanging around.
At 7.30pm, Mars and Saturn keep company with the moon right overhead, as Jupiter starts to creep up on Venus, high in the west.
Of course, Venus will never creep up on Jupiter in reality, this is just line of sight.
Jupiter at present is about 11 times further away.
Same kind of thing with Mars and Saturn.
They may be close to each other in the sky, but Saturn is about 20 times as far away as Mars.
Just north of Mars and Saturn, is the constellation of Aquila the eagle.
Aquila almost looks like a cross, except that its cross-arms are drooping.
Presumably this is what the ancient observer, Ptolemy, saw as the eagle’s wings.
It’s the middle of the wings I want to draw attention to.
There is the first magnitude star Altair.
Altair is one of our nearest stars, but at 17 light years, it is more than a hundred thousand times as far away as Saturn, mentioned above.
Yet, since Altair and Saturn appear about the same brightness to us, you would never have any idea of the vast gulf between our outer planets and even one of the nearer stars.
Altair is somewhat special to me, as when I was a kid my favourite movie was The Forbidden Planet.
The story is around a mission to planet 4 of the Altair system, to sort out this professor who has been posted there but has gone a bit loopy.
I have seen the movie in later years and it still has some impact and scary moments, even given all we know now and all the special effects we are used to in movies like Star Wars and Star Trek.
Even as a star struck kid, I was well aware that you don’t just take a trip to a star in one lifetime, even a local star like Altair.
A round trip to Saturn takes us 10 years, so multiply that by a hundred thousand.
It isn’t on, is it?
And at 17 light years away, just communicating with this professor from Earth would take a 34-year round-trip, or nearly half a lifetime, just to discover he is loopy.
So, Skyping your buddy on a planet around even a nearby star is not on.
The speed of light, or radiation in general, is horrendously fast to us on little Earth.
I can Skype my daughter in UK and her answers come back in a flash.
But in galactic terms the speed of light is snail’s pace.
Anyway, look at Altair shining in the northern sky and ponder who is on its 4th planet.
Next week: Let’s look at our Southern stars.
