cosmolog

time lapse

In a finite universe, if you could see far enough you'd see yourself in the past. If the distance around the universe was, say, one light year, then you'd see yourself as you were a year ago. Then a year later, while you're still seeing yourself as you were a year previously, light from two years ago will arrive.

To be clear : at time zero you are looking forward. After one year you turn your head sideways. At this point the light will be arriving from time zero and from the corner of your eye you'll see the back of your head as it was a year ago, bad haircut and all. You have an instant trim. A year later you'll see the other side of your head (with the supercool hairdo you sprouted at that time) as that light will have completed it's one year journey. Also though, the light from time zero will be arriving again . . . . my question is how does the superimposition work . . . is it literal or more like a hall of mirrors effect ?

A Small Universe

So Jem lives in this universe which is one light year across. This means that, if we shoot a beam of light in the right direction it will hit us one year later. In this universe, space wraps around on itself along certain directions. It has no edges but simply comes back in on itself. The easiest way to think about it is walking on the surface of the Earth. If we travel for long enough along a great circle we will end up where we started. Except in the case of the universe it is not curved like the surface of the Earth.
Now suppose Jem looks in the direction in which the universe is wrapped around itself. He will see light coming towards him from very far sources. From stuff which is close by but also from things that are quite far off. In particular he may, with the use of a telescope, see stuff which is a light year away. Including himself, as he was a year earlier.
He should also be able to see himself as he was two years earlier. Because some light may make the journey twice around the wrapped directions if there is nothing to stop it. Or even, three, four, five and so on, years earlier. The light ray just keeps on going until something (like our eyes, or a telescope) stops it in its path. Except there is one small problem. The moment he sees the light, he stops it in its path. Which means that he will see the light that he has emitted a year earlier, but he won’t see any images emitted in the previous years because he, as he was a year earlier, is blocking their path.
How can he see multiple images instead of just seeing the latest one? Imagine Jem holding out a torch to his side, with his arm slightly bent upwards. He will see the image of himself doing this at the distance of a light year. He will see the point of light slightly displaced from his head. From trigonometry one can work out that the angle is very roughly the distance at which he holds the torch away from himself divided by the distance to the copy of himself, one light year away. But he will also be able to see the torch which is two light years away. In this case the displacement angle will be half as big because one has to divide the distance he holds the torch away from his body by two light years. He will also be able to see the torch as it was three years before. Its displacement angle will be a third of the angle of the closest image. And so on. In fact he will see a series of torches getting closer and closer to his head. The closer the images are to the image of his head, the further away they are from him. By holding out the torch he has been able to avoid block off the light rays,
Is it like a hall of mirrors? The effect is very similar except in a hall of mirrors, all the odd images are reflections while the even image aren’t. Jem will see an alternating series of torches, with alternate sides of the torch as he looks deeper and deeper.

meanwhile, back on earth . . .

A strange trajectory of enquiry has led from the far flung corners of the universe back to earth. Asked to talk about Mike Nelson's "Triple Bluff Canyon", on the basis of being an artist in residence in an astrophysics department, I approached it initially from the point of view of obvious crossovers - entropy, time and instances of multiple universes. Even this initial line of thinking were already rooted in earthly concerns through the installation's references to Robert Smithson and his "Partially Buried Woodshed".

As one thing led to another, a chain of associations unravelled through land art, the pyramids of Egypt, ancient astronomies, geology, geometry, spirals, labyrinths . . . . ending in a collision between the tower of Babel and radio telescopes.

I want to build one of these ! This forms the basis of a design for a working radio telescope constructed from found materials: wood, chicken wire, radio circuits, cable, nails, rope and string. A babelscope, a tower reaching to the heavens, a bowl to catch their babel.

Andromeda

Alpheratz : hotel in Motto Sant Anastasia, Sicily

HR 68 : Fender HR 68 guitar for sale, Mulhouse, France

Mirach : Target Drone, Aberporth, Wales

Almaak aka Almak : re "activities" on Almak St, Issaquah, Washington, USA

HR 154 : resolution congratulating pastor and congregation, Dallas, Texas, USA

HR 458 : lead came, Alchemy Art Castings, Hamilton, Ontario, Canada

HR 163 : Resolution to reintroduce the draft, Washington DC, USA 2004

place your bets

Danny Hillis is prepared to wager that the universe will eventually stop expanding. A pioneer of long term thinking and a man of gargantuan intellect he is not to be taken lightly !

Cepheus

Al Rai : newspaper, Jordan
Alfirk : webserver, Deakin University, Melbourne, Australia
Alderamin : USS Alderamin, Iwo Jima, 15/8/1945
Iota : Iota, Louisiana, USA
HR 8417 : line output transformer, Donberg Electronics, Ranafast, Co. Donegal, Ireland
The Garnet Star : earings, Macrosun, Delmar Bvd, St Louis, USA

Rocket Ship

12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, blastoff !

You say you're too young to love a man like me
Just because you're 13 and I'm 73
Well I realised the solution lies in relativity
Space and time ain't absolute, so said Albert E

But I'm going to need
A rocket ship, rocket ship, rocket ship, rocket ship, rocket ship, rocket ship, rocket ship, rocket ship . . .

Well I got myself a rocket ship and flew off to the stars
Travelled at the speed of light, stayed a way for a couple of years
According to my 'rithmatic and assuming I survive
When I return I'll be 74 and you'll be 65

Then will you love me
Then will you kiss me
Will you have missed me
When I step down from my

Rocket ship, rocket ship, rocket ship, rocket ship, rocket ship, rocket ship, rocket ship, rocket ship . . .

This ain´t such a fine mind
I ain´t no Einstein
Now I'm here and you're gone
There's a tombstone with your name on
Somethings gone very wrong
I stayed away too long

On my rocket ship, rocket ship, rocket ship, rocket ship, rocket ship, rocket ship, rocket ship, rocket ship . . .

I saw the rings of Saturn, saw Jupiter and Mars
Fade in my rear view mirror when I flew off to the stars
And now I'm back at the chicken shack and a pretty girl I spy
Same old problem, same solution, back to space I'll fly

On my rocket ship, rocket ship, rocket ship, rocket ship, rocket ship, rocket ship, rocket ship, rocket ship . . .