SAY WHAT?
Stuff you don’t need to know, and yet
SIRIUS is the brightest star in the night sky and easy to locate. But when you look at it tonight, you’ll be seeing it as it was 8.6 years ago: that’s how long it takes the light it reflects to reach earth. The rays of the sun take about 8.5 minutes to reach us.
Last year, the Hubble Space Telescope detected the light of a star so far away that its light takes 12.9 billion years to reach earth. The star existed when the universe was a mere 4 billion years old.
If you scream in space, no one will hear you. There is no atmosphere, so no medium for sound to travel in. Unless, of course, you use a radio to transmit sound: radio waves can be sent and received in a vacuum.
There are many, many times more stars in the universe than grains of sand on the beaches and deserts of our planet. Scientists can’t really reliably estimate how many stars there are, but some have offered the number of 70,000,000,000,000,000,000,000. There are between 200 billion and 400 billion stars in our galaxy, the Milky Way, and the same clever people will tell you that there are at least 2,000,000,000,000 galaxies in the observable universe.
More than 600 people have been in space, the first being Russia’s Yuri Gagarin on April 12, 1961; the second was US astronaut Alan Shepard, who got there 23 days later on May 5.
Neutron stars are the smallest and densest stars in the known universe with a radius of only about 10km but a mass several times that of the sun. They can spin 600 times a second.
Scientists at Yale University believe there is a planet, 55 Cancri, with a surface made up of graphite and diamonds. It can be seen without a telescope in the constellation of Cancer, but it is 40 light years away. Sorry, De Beers.
Millions of years from now, if we don’t destroy our planet long before then, a favourite question in a pub quiz may be: what is the longest-surviving mark left by Homo sapiens? The answer will be the footprints on the moon made by Neil Armstrong on July 20, 1969. The moon has no atmosphere, therefore no wind or water to destroy the footprints.
♦ VWB ♦
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