Saturday, April 28, 2012

Things we don't understand. Yet.

One of the most powerful words in the scientific vocabulary is “yet”. As in “We don’t know the answer to that question. Yet.”

It’s one of the biggest challenges that the opponents of science face, trying to understand how scientists and the followers of the scientific approach can cope with not knowing things. It’s particularly hard for those followers of belief systems who offer fake certainty, all-encompassing but wrong explanations for life’s challenges and a bogus absence of doubt.

In fact science actually welcomes doubt and uncertainty. After all if the scientific method provided all the answers it would simply stop. There’d be nothing left to do, no more findings to find, no more fun to have.

The greatest of all the uncertainties we face at the moment is also the simplest to understand. Where the hell is everything?

c/o Wikipedia
Our current understanding of the universe suggests that most of the matter out there in the universe is missing. The way the galaxies are moving in relation to each other suggests that there should be a lot more “stuff” out there than we can see. Only a huge amount of missing matter could explain why the galaxies are gravitationally attracted to each other as strongly as they are. We’re pretty sure it’s out there somewhere but we just can’t see it. That’s why it’s called “dark”.

And it IS a big chunk. The mathematics suggests that something over 80% of all the matter that exists is this invisible, dark matter.

This is the biggest puzzle in physics at the moment and astronomers and theoretical physicists all over the world are doing their best to come up with a suggestion about what this stuff might be. The current consensus is that it’s not matter that’s simply hiding, it must be something entirely new, something that we simply don’t know how to detect. Yet.

For scientists this is as good as it gets. The uncertainty, this gap in humanity’s knowledge is the sexiest thing they can imagine. In order to find this dark matter they’ll need to develop new theories, new experiments and new observations that can help us solve the problem. They’re going to have to push themselves and their imaginations to the limits.

A good example of a problem that was eventually solved was the seemingly bizarre behavior of the Pioneer space probes. These were launched in the early 1970s to explore the outer planets and achieved spectacular results. After this was over a strange thing happened. As these probes disappeared into the depths of space it was noticed that they were slowing down a bit more than expected. The mission controllers knew that this would happen a bit because of the combined gravitational pull of the Sun and the planets but their calculations couldn’t explain why it was slowing down as much as it was.

A huge variety of explanations have been proposed but none seemed quite right. Scientists were puzzled and didn’t have a good explanation. Yet.

Now they have. After trawling through vast amounts of data they’ve worked out a very persuasive explanation. It’s not interplanetary material, it’s not aliens, in fact it’s nothing extraordinary at all. The solution is almost mundane but it’s still elegant. It turns out that the on-board power generators, like most power sources, radiate small amounts of heat, but the heat on the Pioneer probes wasn’t radiating equally in all directions. More thermal radiation was shining forwards, in the direction of travel, than backwards towards the Sun. It’s as if the probe was shining a torch ahead of itself. That tiny amount of “photon pressure” accounts for the tiny deceleration of the Pioneer probe.

I think this is a very good example of how a puzzle was eventually solved using old-fashioned scientific methods. The answer remained unknown for a while but eventually it was resolved. Like they all will, sooner or later. However, there is a point that it’s critical to understand. Unlike some so-called scientists in the distant past, who predicted that one day ALL scientific problems will be solved, I don’t agree. For every problem that science answers, at least one more emerges. It’s a constant struggle against ignorance. It’s also a constant fight against the peddlers of deliberate ignorance like religious fundamentalists, the peddlers so-called “alternative” medicine and the quacks who want your money.

One day we’ll beat them. Just not yet.

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