2018-10-25

Why interested in astronomy

This is an article (or a note, to be more precise) called "Note to self (and others): Why I'm interested in astronomy." that I wrote on Facebook, back in November 2010.
Read, contemplate and enjoy!
/Christofer Döss

Some 80 years ago we started to broadcast TV signals. Every TV signal, every program, every TV show and every film that has been broadcasted through air since then has been transmitted not only to our TV devices but straight out into space as well - as one can hear in the "Contact" movie clip, at http://www.facebook.com/video/video.php?v=466063228672.
The speed of light is almost 300,000 km/second and the distance light makes on a single year is called a light-year.
As electric signals, as well as TV signals, are transfered on wire, in air and in space at a speed close to the speed of light, TV signals has been wooshing thru space for 80 light-years. Follow?
Now we come to the interesting part! 
Our nearest star is of course our own sun. The next nearest star is the "well known" star called Alpha Centauri. That star is only 4 light-years away...! Not even the 50th(!) closest star is close to our first broadcasted TV signals! That star, called DEN 0255-4700, is only 16 light-years away! 
That put one's thoughts in some perspective huh! 
And people are wondering why I'm interested in astronomy...! 

Addendum 1:
The estimated age of the universe is 13.75 ± 0.17 billion years, since the time of the Big Bang. That is: The light from that early Big Bang has been traveling for 13.75 billion years...
In other words: Universe is 13.75 billion light years across!
https://spaceflashnews.blogspot.com/2010/05/stor-skillnad-for-liten-bit.html 

 












Addendum 2:
Another aspect of distances is this:
- The light from our moon takes 1 second to reach us on earth
- The sunlight needs 8 minutes to enlight our lives
- The radio signals from the NASA space probe New Horizon, on its way to the dwarf planet Pluto and beyond (estimated flyby of the Pluto system on 14 July 2015), needs 4 hours to reach earth. 
- The Voyager spacecrafts 2 and 1 (launched by NASA in 1977) needs some 15 and 18 hours "of light travel time" to reach earth.  The signals from the Voyager spacecrafts that is.
https://twitter.com/spaceflashnews/status/769047199477014528