Tag Archives: moon

15 – New friends and a stairway to heaven

img_5866The country starts to change north of Carnarvon. It’s more like desert with long lines of red dunes marching across the landscape. The road is excellent – until we reach the road works. It has to happen, though, so we wait in a queue with good humour. I took the chance to take what I think’s a stunning photo.

img_5874aFurther on, low ranges of hills appear. They’re old and scarred, crumbling into the plain, but not in our lifetime. The hills help to hold the water. There are rivers here – obvious, really. Just look for the river red gums.

The trees advertise a river - and if you missed that, there's a bridge

The trees advertise a river – and if you missed that, there’s a bridge

I love the colours in the Pilbara

I love the colours in the Pilbara

Karratha wasn’t our favourite stop in 2013 – but this time we were staying with friends we’d met on a river cruise in Europe. It makes a HUGE difference when you have friends who know the area. Our first evening was a backyard barbecue and lots of talk.

As it happened, our visit to Karratha coincided with a full moon in a cloudless sky, coinciding with low tide. Karratha has an east-facing bay, which means the moon rises – if not quite out of the sea, very nearly. So the reflection of the moon in the water as it rises gives the impression of a path or staircase to the moon.  The Karrathians celebrate this event in the usual way – 4WDs backed up to the beach with the trays down to hold the tinnies and bottles, and the finger food. We all turned up not long before sunset for a convivial drink and a walk in the shallows of Hearson Bay.

Apart from our hosts, Vicky and Bruce, another couple who had also been on that European cruise was also there. It was lovely to see Alison and Phil again – especially since Ali had brought along a bottle of rose she’d bought at one of our stops in Germany. I was happy to help her drink it.

And now for the staircase to the moon.

The sun has disappeared

The sun has disappeared – just. The last light brightens the rocks

And now we wait - enjoying the evening

And now we wait – enjoying the evening

Here it comes - rather later than we though - but hey - good company, nice drinks

Here it comes – rather later than we thought – but hey – good company, nice drinks

And here she is in all her glory

And here she is in all her glory

A little bit of moonshine in the night

Picture of partial eclipseA lunar eclipse happened in my part of the world on 28th November, hard on the cosmic heels of a solar eclipse earlier in the month. As it turned out, the penumbral eclipse was a huge disappointment. No shadow across the moon’s disc, not even a reddening of the light. So the cirrus cloud partially obscuring the view didn’t matter much. We had moonshine as we always do and the photos were a fizz.

However, it got me to wondering about moons; ours, and other moons in general. To start with, let’s mention the eclipse – the truly spectacular solar eclipse that happened earlier this month. It was a partial eclipse in my part of the world, but even so it is a special event. But why is it so? The moon is tiny compared to the sun.

An extraordinary cosmic coincidence

The sun is about 400 times the moon’s diameter and about 400 times as far way from the Earth and that ratio means that when the moon comes between the sun and the Earth, that shadow is just about a perfect fit.  That relationship is a coincidence. Evidence indicates that the Moon was once closer to the Earth and is gradually moving away, so enjoy your cosmic moment, knowing that in the distant future, there will be no total solar eclipse.

That factoid is not the only extraordinary thing about our moon. Not at all.

It’s not the largest moon in the solar system. In fact, going by this list it comes a creditable fifth after Ganymede (Jupiter iii), Titan (Saturn vi), Callisto (Jupiter iv) and IO (Jupiter i). Indeed, Ganymede and Titan are both larger than Mercury and let’s not talk about poor Pluto. Really, when you think about it, it makes perfect sense that the largest planets have collected the largest moons.

Except ours.

Why is this so?

I have in my possession a tattered little paperback, a collection of essays on astronomy by Isaac Asimov (Asimov on Astronomy, Coronet, 1974). One of the things I loved about Asimov, who had a PhD in chemistry and an interest in everything scientific, was that he could explain complex physics in a way that an interested amateur with absolutely zippo mathematical ability could understand. He wrote papers regularly for magazines and the like and subsequently, they were published in book form. This little volume is a treasure trove of scientific fact and some intriguing speculations. True, some of it is now dated, since it was published before the epic discoveries of Voyagers I and II. Pluto had not yet been demoted. And yet before it could be proved he predicted that many planets other than Saturn would have rings.

To get back to the point, one of these essays is entitled “Just Mooning Around” in which Asimov talks about the gravitational effects of the sun, the planets and the moons in the solar system have on each other. Without going into all the details of the paper, he talks about the ‘tug of war’  ratio, which argues that in most cases, the gravitational attraction of a planet on its moons is vastly greater than the pull of the sun on those same moons. There is also a kind of ‘goldilocks’ zone around a planet in which a true moon would exist (as opposed to loosely captured satellites like Neptune’s Nereid). A moon must be between a minimum Roche limit and a maximum ‘tug of war’ distance. For the mind-bending number-crunching, go read it yourself – I told you I can’t do maths. However, I can appreciate logic. And you will see it is so.

According to his theory, of the four innermost rocky planets, Mercury could not have a moon because it has no ‘goldilocks’ zone. The other three are highly unlikely to have moons because of the narrowness of the ‘goldilocks’ zone. And indeed, Mercury and Venus do not have satellites, and Mars’s Phobos and Demos are overlarge potatoes which are expected to disintegrate.

I see you jumping up and down. What about us? Earth and that thing up there?

Ah, Asimov argues that the Earth/Moon pair is not a true planet/moon relationship because the Moon is so much larger in comparison with its primary than any other such relationship in the solar system. By a long way. He suggests that the Earth/Moon combo is really a binary planet, waltzing its way around the sun. Of course, all planets with moons have a wobble in their orbit but the Earth/Moon shimmy must be quite pronounced. Certainly I don’t think there’s much disagreement these days that our Moon was derived from the same stuff as the Earth. This article suggests accepted theory is that a Mars-sized object collided with the Earth, aggregating the material and spewing off a portion which later formed the Moon.

The next thing you have to wonder is – how important is that massive moon to life on Earth? But that’s another topic, isn’t it?

Isn’t science wonderful?

An unforgettable milestone in the journey of life

I woke this morning to the news that Neil Armstrong had passed away.

To me, that means two things; the end of an era and that unenviable feeling of being old. The things I’ve seen, the things that are a part of the parade of my life. On Twitter I learned a friend’s husband had been born just before that day in 1969; on Facebook another friend talked about reading a book about 9/11 and mentioned that there are teenagers around who were babies when the twin towers came down. So true. Milestones in the wheel of life. And sure, there are days, like JFK’s death, 9/11, the Japanese earthquake, Chernobyl, that are etched into my brain with acid. But the ones I look back on with pleasure and pride are the space days.

I was 18 when Apollo 11 left for the moon, in my second year of a BA degree in history. Like many of my colleagues, I stayed home to watch history being made. The whole western world quivered with excitement. President Kennedy’s goal of a man on the moon within a decade was about to be fulfilled. We’d seen the dark side of the moon from Apollo 10 (and the Russian probes, but we won’t go there). And now it was all about to happen. You’ve all seen the pictures as the three men in their bulky suits took their last walk to the tiny, tiny module on the top of the Saturn V rocket. So did we, on CRT TVs.

Now was the day, morning in Perth, Australia, and I sat on the edge of my seat in the lounge room, eyes glued on the TV while on the other side of Australia the signals came in to Parkes. We never knew, of course, that Armstrong had taken over landing the module himself, looking for a flat piece of Moon. Never knew he had 30 seconds of fuel left. That came out later. I peered at grainy black-and-white footage. First, the lander’s leg resolved itself and then you could just make out the ladder. Then a boot appeared and Armstrong eased his body down onto an unknown surface and uttered his famous words, ‘that’s one small step for mpicture of Apollo 13 posteran, one giant leap for mankind’. Even then I wondered how long he’d been rehearsing; and who had written it for him. Here’s the footage

The next few days went by in a blur of extra-terrestrial shots of footprints on an ancient landscape, attempts to raise a US flag fitted with an arm because there was no wind, the famous photo of the moon reflected in a visor. Buzz Aldrin and Neil Armstrong cavorted like a couple of kids in the weak gravity, while Collins stayed up there in the capsule. I held my breath on that final day when they blasted off to dock with the capsule and cheered when they splashed down in the Pacific.

It was years later before we all began to realise how dangerous the whole thing had been. These men were pawns in a race with the USSR – which had its own pawns, of course. NASA took a lot of risks and I’ll bet Mission Control had its fingers crossed many a time. What happened on Apollo 13 is a case in point. If you don’t know, go see the excellent movie of the same name, starring Tom Hanks. So the USA won the race. But interest waned quickly; the last manned flight, Apollo 17, was in 1972 and we don’t look like going back any time soon.

But Neil Armstrong’s name is in the history books forever. A brave but humble man who stood on the edge of eternity.