radio waves – Mallaband-Brown

Only 93 million miles away. The sun sets… But it really set 8 minutes earlier! It’s just that light takes that long to get from the sun to us.

OK, now look up at the stars. Some of them are actual stars and others are nebulae and galaxies.

Light takes time to travel. They talk about light years, some stars are only a few light years away. Some are thousands, or millions, or billions of light years away.

Now think about radio waves. They travel at the speed of light too… So TV and radio signals from Earth started travelling from when we first broadcast radio back in the 1920’s or 30’s? Thats a sphere around the Earth with a radius of about 90 or 100 years. So a planet 90 light years away might just about be hearing our signals. Imagine what they would do. They can’t travel here at the speed of light, but they might reply, but that will take 90 years to reply. Closer stars could have planets that reply sooner. But it’s still going to be a boring conversation!

I was pleased to find this picture of the Jodrell Bank Observatory in my Facebook memories recently. I think it’s from about 2012.

Jodrell Bank radio telescope was built on the Cheshire plain in the 1950’s near Holmes Chapel. It was built there because it was far enough away from the radio noise given out by big cities like Manchester and Liverpool.

The radio telescope is a large dish shaped telescope, supported by a massive superstructure. Part of it was made from two gun turrets from world war two battleships that act as the pivots for it. The dish can rotate around its axis and from horizontal to vertical so it can scan most of the northern hemisphere.

It’s worth a visit for the day (covid safely). There is an arboretum, the radio telescope, a discovery centre and other interesting exhibits. Check their website for details at https://www.jodrellbank.net

Mallaband-Brown

Tag: radio waves

Sunset

Jodrell bank