Seriously Amazing Science 2 (links)

A post at Centauri Dreams suggest that instead of building very large interstellar probes (and their inherent logistic problems), we could look into building a swarm of very small ones. There are probably a whole bunch of story indeas incorporated in this very interesting post.

This coming Friday, 5 August, the Juno spacecraft takes off for a mission to Jupiter. Believe it or not, there are Lego figures aboard. One can only wonder at what the aliens (or future humans) are going to think when they find it. As aside here is a picture of the Lego figures in question.

New dwarf planets and other objects continue to be discovered in the vicinity of Pluto.

Astrobiology Magazine examines the influence of the absence or presence of a moon on a planet’s stability.

Scientists announce they have found signs of liquid water on Mars. Watch this space. There have already been models that suggest that in small micro-environments liquid water could exist on Mars. We may well find it sooner rather than later.

And this is just too silly to be true, but it seems it is: a man builds a nuclear reactor in his kitchen. Somewhere on my hard drive, I have a story about some Ethiopian thugs cobbling together a fusion reactor that ends up working a little bit better than they expect. I shelved it a while ago as being ‘too stupid’. Maybe it’s time to pull it out again…

What if the Earth had no moon (part 2)

A while ago, in this blog post, I mused about what the earth would be like with no moon. You may hear the Moon blamed for things as diverse as reproductive cycles and people’s moods, but in that post, I argued that if all of a sudden, we’d find ourselves without a moon, not a great deal would change. The Sun causes tides, albeit smaller ones, and any stability issues of the Earth’s axis would not change overnight.

But this is not a realistic scenario. The Moon isn’t going to just disappear (the subject of Death Star-like blasting a planet apart is a subject for another blog post, but let’s just say it’s physically nigh impossible). The real question I should have asked is: what would life on Earth be like if Earth had never had a moon? If the Pluto-sized object that may or may not have collided with us to form the Earth and Moon as we know them had missed the Earth, and sailed straight on, to eventually burn up in the Sun.

The situation would look vastly different. The Earth-Moon system is vastly different from other known planets in terms of relative size. Only the largest moons of Saturn and Jupiter are similar in size to our Moon, but those planets are of course much more massive. The Earth-Moon system could well be referred to as a double planet. Of course Earth and Moon affect each other, and this influence comes in the form of gravity. While the gravity of the Moon affects all surfaces of the Earth equally, it’s only the oceans that can react to this gravity. Yeah, that’s how the tides are formed.

Imagine the Earth as an oblong bubble of water, with bulges both on the side where the Moon is at and the opposite side. This bulge orbits the Earth at the rate the Moon does. But the Earth itself rotates inside this envelope of water, and this creates friction at the place where water and solid surface meet. In effect, the water is forever trying to keep up with the planet. Friction creates warmth, and yes, loss of speed.

So it is that over the four-plus billion years of the Earth’s lifetime, the rotation speed of the Earth has slowed from an eight-hour day to our current twenty-four hours. Is still slowing, in fact.

Of course life on a planet with days of eight hours would be very different. We’d experience vastly more powerful weather and especially wind systems. With a rotation speed like that, there would probably not be much opportunity for much North-South weather movement, but we’d have strong bands of air movement, much like Jupiter (which has a daylength of ten hours). We’d have similar ever-lasting cyclonic systems.

And what would it do to the seashores, having the tides jump up twice in eight hours?

Or to the biology of animals evolving with that kind of daylength? Would we all have nervous tics from seeing the Sun whizz by?

More reference books for the SF writer

I’m in various stages of reading all of these.

Foundations of Astronomy by Back and Seeds, 2010. Make sure you get the International edition, since you do not want to wrangle miles and pounds and other non-metric nonsense. Very accessible basic and less basic information about everything in space.

Titan Unveiled by Ralph Lorenz and Jacqueline Mitton, 2010 edition. All the latest about Titan. Written in non-scientific style.

Unmasking Europa by Richard Greenberg 2008. Latest information on Jupiter’s moon Europa. More scientific in style than previous title.

The Starflight Handbook by Mallove and Matloff 1989. This was recommended to me by the good people of the Analog forum. Although published a good while ago, there has been little change in the basic concepts and ideas. It’s making the ideas work that’s the hard part. If your setting includes anywhere near realistic space travel, I’d put this on your must-read list. Even if you decide to hell with the laws of physics, you know what principles you are breaking, and you know where to insert your magic device.

I bought all these books through abebooks.com