DARK SKIES: Space-age questions from near and far
AS AN astronomer for over 60 years and operating the Kingaroy Observatory (formerly Maidenwell Observatory) for the past 14 years, I have had many astro questions popped to me by our visitors, regarding the universe.
While some questions have been of a technical nature, rather than take up their observing time, I just say let's talk about that over a cuppa, after the show.
One such tech question asked was about space-time.
My answer was: "According to Albert Einstein's theory of special relativity, it says that time slows down or speeds up depending on how fast you move relative to something else, but when you have nothing to go by in a void of emptiness, it's a lot harder to measure. Approaching the speed of light, a person inside a spacecraft would age much slower than his twin at home. Also, under Einstein's theory of general relativity, gravity can bend time”.
I'll explain more about the latter when I have proof.
Non-technical questions are answered during the show using simple analogies, so they can get a 'handle' of that answer.
For instance, "Do stars actually exist?”
From decades of research with powerful telescopes, it has been found a good portion of stars we see at night, may not exist, as we have no way of telling if they're still "alive” or have 'died' as the starlight we see now, left on its journey multiple tens of thousands of years ago.
Before we start showing cosmic wonders through our telescopes to our visitors, we show and tell in simple English, some images of an open or globular cluster, a nebula, a galaxy and so on.
This helps them to relate to that object when they get to view it in the telescope.
To explain a star, we asked: "What is Earth's nearest star?”
Someone will say, the sun. Correct! for that is what a star is, a very distant sun.
Then we explain what a light year is, which is the time it takes a particle of light called a photon, to travel in one Earth year at 300,000km/second or 10 billion, 800 million km/h.
At that speed you could make 7.5 orbits of the Earth's equator in one second, just over one second to the moon, 8.5 minutes to the sun five minutes to Mercury, 3.5 minutes to Venus, 20 minutes to Mars, 40 minutes to Jupiter, an hour to Saturn and about four hours to Pluto.