Enjoy a night of stargazing at Maropeng
Did you know that Mars' sky is pink, that the Evening Star is actually a planet, or that Jupiter has over 60 moons?
These are the kinds of fascinating facts Vincent Nettmann, Maropeng’s resident astronomer (Nettmann calls himself a 'public astronomer'), sprinkles as he speaks, entertaining guests with his friendly and conversational tone, and information-packed anecdotes about our solar system and universe.
Each month, Nettmann hosts a stargazing event and adapts his talk to a relevant topic (depending on what’s visible) at Maropeng, the official visitor centre of the Cradle of Humankind World Heritage Site, which is just over an hour’s drive from both Johannesburg and Pretoria.
You’re advised to arrive at about 5pm (in time for some good evening photographs in the last light, which often makes Maropeng and the Cradle of Humankind look especially beautiful). Then enjoy drinks in the Maropeng foyer, followed by Nettmann’s talk, a buffet dinner in Maropeng’s Tumulus Restaurant, and stargazing through several large telescopes on the expansive balcony outside the restaurant, assisted by Nettmann and his knowledgeable assistant, Sheldon Herbst.
Reasonably priced at R295 per adult and R165 per child (ages four to 14), this makes a good family outing, though it’s not ideal for very young children (highly recommended, though, for ages about 10 and up). You could also treat yourself to a night afterwards at the Maropeng Hotel, which has some of the best views in all of Gauteng.
Even if the weather is cloudy, Nettmann goes all out to pack his talk with interesting information and comparisons, and to, as he said, 'edutain' his audience throughout.
On the evening I attended, Nettmann’s talk focused on the Italian genius, Galileo Galilei (1564 to 1642), who is widely regarded as the first modern scientist.
In 1609, Nettmann explained, Galileo first looked through a telescope, though he didn’t invent it. This honour belonged to Dutch optometrist Hans Lippershey, who, according to Nettmann’s entertaining repartee, made some inverted lenses the previous year by mistake and threw them away. Lippershey’s children picked up the lenses and were delighted by their telescopic powers (they had a magnifying power of about three times normal vision), and Lippershey quickly patented the idea for a telescope (there were others polishing their newly invented lenses with the same idea). A sad corollary is that Galileo eventually went blind from looking through darkened glass at the sun while trying to study sun spots (Nettmann reminds you never to look at the sun through binoculars).
Our sun, explained Nettmann, was formed about five billion years ago and is a dwarf star (there are some stars in the universe 600 times the size of our sun), and is mostly made up of hydrogen and helium. Its core temperature is over 15-million degrees Celsius. While it’s a nuclear furnace today, it’s been estimated that the sun will burn out in about five billion years’ time. It would take you about 17-and-a-half years to reach the sun in a jumbo jet, Nettmann helpfully pointed out.
Then he spoke about the Earth.
The mass of the Earth is 5 973 600 000 000 000 000 000 000 kilograms (5.97219 × 1024 kilograms) and it’s spinning through space at about 30 kilometres per second. The Earth, he said, is a terrestrial planet, along with Mercury, Venus, Earth and Mars (the others comprise mostly gases).
Earth’s moon is about 384 000km away, and is about a quarter its size, with a diameter of just under 4 000km. It would take you four months and 10 days to get to the moon if you drove consistently at 120km/h, Nettmann said. In 1969, Apollo 11 moved a little faster than that on its way to land on the moon on July 20 – it had a top speed of about 40 000km/h.
Venus, Nettmann explained, is often the brightest object in the sky after the moon. It’s sometimes known – erroneously, as it’s a planet – as the 'evening star' and sometimes as the 'morning star'.
Mars, known as the 'Red Planet' as it is reddish in colour due to the amount of iron in it, is about 60-million kilometres away from Earth on its closest approach to us. Mars has a pink sky unlike our blue sky, and is home to a huge active volcano known as Olympus Mons (Mount Olympus in Latin), which is about 22km high and 600km across, making it the largest known volcano in our solar system.
Mars is also home to a canyon that is 7km deep in parts and about 4 000km wide – enough to stretch across the United States, making the Grand Canyon, the largest in the world, look a little, well, ditch-like (the Grand Canyon is 'only' about 1.6km deep and about 800km long).
For this canyon (named Valles Marineris, or Mariner Valley) to have formed, said Nettmann, there must have once been a massive amount of water on Mars. And, he explained, red doesn’t equate to warm, though – Mars is actually a very cold planet, with temperatures dropping to -120 degrees Celsius in winter. Mars is just bigger than half the size of Earth, and is about double the size of our moon.
Jupiter has over 60 moons – four of them discovered by Galileo. One of Jupiter’s moons is named Io, which is smelly, sulphurous and fiery, and is home to over 2 000 active volcanoes. Another, Europa, is the most similar body to Earth yet found, Nettmann said. It has lots of water like Earth. Nettmann asked: 'Is there nascent life in it perhaps?'
Saturn is 10 times the size of the Earth and is the 'darling of astronomy', with a ring around it that is half-a-million kilometres across. Saturn also has more than 60 moons, including Titan, its main moon.
To find out more fascinating information about our solar system and the universe, you’ll have to adjust your trajectory and propel your rockets towards Maropeng. Whatever the weather (which is usually good anyway), your mission can’t fail.
- Visit the Maropeng website (www.maropeng.co.za) for more details about upcoming stargazing events, or call +27 (0)14 577 9000.
- The Maropeng Visitor Centre and the Maropeng Hotel are located just off the R563 Hekpoort Road, Sterkfontein.