Light

The non amateur stuff. Hawking, black holes, that sort of thing

Moderators: joe, Brian, Guy Fennimore

Moonstruck
Posts: 91
Joined: Thu Sep 22, 2005 2:47 pm
Contact:

light

Post by Moonstruck »

delete
Last edited by Moonstruck on Tue Dec 06, 2005 8:07 pm, edited 1 time in total.
joe
Site Admin
Posts: 4382
Joined: Fri Dec 03, 2004 11:24 am
Location: Greenwich, London
Contact:

Post by joe »

Thanks Cliff and Dave re: Zwicky. Are there any astronomers called John Smith or Bob Perkins? :shock: Baade, Zwicky, Halton Arp!! Harlow Shapley, Hubble, Clyde Tombaugh, Oort, Whipple, Burbidge, Bok, Slipher, Hertzsprung....... :arrow:
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
stella
Posts: 1473
Joined: Fri Dec 03, 2004 2:41 pm
Location: 55° 57'N: 03° 08'W
Contact:

Post by stella »

" Are there any astronomers called John Smith?"

I was once asked if I knew John Smith, the astronomer. After puzzling a bit, I realised that they were talking about John Brown. So even with Smith and Brown , you can still get it wrong.
As for difficult names, I hope you are all practising 'Schwassmann' and 'Wachmann'
:o
joe
Site Admin
Posts: 4382
Joined: Fri Dec 03, 2004 11:24 am
Location: Greenwich, London
Contact:

Post by joe »

Ah! John Brown, the discoverer of low-mass failed dwarf stars that bear his name? (Drumroll... cymbal) :roll:
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
stella
Posts: 1473
Joined: Fri Dec 03, 2004 2:41 pm
Location: 55° 57'N: 03° 08'W
Contact:

Post by stella »

Err No, John Cambell Brown, the Astronomer Royal (for Scotland).
joe
Site Admin
Posts: 4382
Joined: Fri Dec 03, 2004 11:24 am
Location: Greenwich, London
Contact:

Post by joe »

I know. Just pulling some legs while I wait for paint (watercolour) to dry.
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
Moonstruck
Posts: 91
Joined: Thu Sep 22, 2005 2:47 pm
Contact:

Light

Post by Moonstruck »

delete
Last edited by Moonstruck on Tue Dec 06, 2005 8:07 pm, edited 1 time in total.
joe
Site Admin
Posts: 4382
Joined: Fri Dec 03, 2004 11:24 am
Location: Greenwich, London
Contact:

Post by joe »

1 Watt = 1 joule of energy per second. It's a measure of energy used over time.
1000 Watts = 1000 joules of energy per second
1 kilowatt hour = 3600000 Joules of energy (described as the amount of energy a one watt appliance uses in one hour)

A year is a measure of time = 31536000 seconds
A lightyear is a measure of distance = 31536000 x 300000 (the speed of light km/s)

In one second light travels the distance of 300000 kilometres.
In one minute light travels the distance 18000000 kilometres.
In one day light travels the distance 432000000 kilometres and in one year it travels the distance 9460350000000 kilometres.

This last distance, 9460350000000 kilometres, has been given the name Lightyear just to confuse everyone.
Last edited by joe on Thu Oct 20, 2005 5:00 pm, edited 3 times in total.
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
stella
Posts: 1473
Joined: Fri Dec 03, 2004 2:41 pm
Location: 55° 57'N: 03° 08'W
Contact:

Post by stella »

Isn't a light-year equal to 9 460 350 000 000 kilometres?
:?:
joe
Site Admin
Posts: 4382
Joined: Fri Dec 03, 2004 11:24 am
Location: Greenwich, London
Contact:

Post by joe »

Thanks stella (again), it is and I've corrected it. Don't know why I put that other figure down or where I got it. :oops:
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
Post Reply