JJ’s Galactic Musings – Exploring our planet

Welcome to the galaxy! I’m J J Mathews, New Zealand science fiction author and dreamer of alien worlds.

Our focus this month is more ‘down to Earth’, but with references to our celestial neighbours as we examine some of the forces of nature that affect our home world.

February is under way and the New Zealand days are already getting a little shorter (2 minutes per day at our latitude). Still warm and summery, but we recently had a bit of a heatwave, with a number of days reaching 34 degrees C (100F) or more at the end of January, with February starting around 27-28C (86-90F). February is usually the hottest month in New Zealand, so we can expect some hotter days to come.

Below are some photos of our recent family trip down to the bottom of the North Island, and a drive around Mt Taranaki (a near-perfect-shaped volcanic cone), followed by a short trip to Rotorua (in the geothermally active centre of NZ).

Below: Sunset on the beach, Kapiti Coast, NZ (Kapiti Island in the background)

The trip held reminders of the forces of nature that surround us every day, and lurk beneath our feet. From the gentle, gradual erosion of rocks on the shore from constant wave action to geological features further inland, we take much of our environment for granted. However, our planet is ever restless, and there are many, many planets (and even moons) out there that may be similar to ours… and yet very, very different.

From the familiar Earth to the dry, dusty surface of Earth’s Moon, to the wind-swept plains of Mars and its buried hoards of water-ice, to the ice moons of Jupiter, the many forces of nature act in curious ways upon each celestial orb.

While we enjoy the liquid waters of a salty ocean lapping at a beach on Earth, the ice moons of Jupiter hint at liquid oceans deep beneath a thick crust of ice. In contrast, the sands of Mars have not seen liquid water flowing on their surface for quite some time, but many postulate that water once flowed there freely.

Below: Mt Taranaki/Egmont, New Zealand

In terms of volcanoes, none can compare to Olympus Mons on Mars, which, at 25km high, is almost triple the height of Mt Everest (8.8km), and over three and a half times the 6.9km height of the Ojos del Salado volcano in Argentina/Chile, the highest volcano on Earth. In comparison, Mt Taranaki in New Zealand (pictured above) is a mere 2.5km high, but the base is just above sea level. Mt Taranaki was most recently active 250 years ago.

However, Mt Taranaki is not the largest volcano in New Zealand. That title goes to the Taupo supervolcano, which has Lake Taupo filling the bottom of the huge volcanic crater, a mere 356 metres above sea level. The surface area of the lake is 616 km2 (238 square miles). How big is that? The lake is 46km (28.5 miles) long and 33km (20 miles) wide, and the crater rim rises around it on all sides, touching on the Tongariro volcano to the south. The crater itself is over 1000 sqkm in area, and is one of the most frequently active and productive rhyolite volcanic calderas in the world. The most recent major eruption was 1800 years ago, and the sound of that eruption was recorded in both Rome and China. There have been 26 smaller eruptions since then, and the caldera is actively monitored, with small quakes being recorded on a regular basis.

Below: Pohutu geyser, Rotorua, New Zealand

Not all eruptions involve rock and lava – geysers can be found in geothermally active regions wherever the Earth’s crust is thin and magma comes close to the surface. When mixed with fresh inflows of water seeping into deep cracks above the magma pockets, pressure builds up and is released in spectacular displays as super-heated water and steam shoot up out of the ground. The Pohutu geyser in the Whakarewarewa thermal area is the largest active geyser system in the southern hemisphere, with eruptions twice an hour that can reach up to 30 metres (100 feet).

But Earth is not alone in producing geysers. The Galileo spacecraft observed the existence of icy plumes erupting from Europa’s surface, implying the existence of a vast liquid ocean beneath its icy crust.

No matter where humankind may venture to out into this big galaxy, it is certain that among the many wonders that are waiting to be found, we will find the familiar among the exotic. And, perhaps one day soon, they may find other life out amongst the stars, or even evidence of life on our closest neighbours.

But for now, we will have to make do with stories of the familiar in far-distant, exotic places, mixed with the wildly exotic in familiar locales as authors continue to stretch the realms of the human imagination.

“There are those that look at things the way they are, and ask why? I dream of things that never were, and ask why not?” – George Bernard Shaw

J J Mathews

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