Saturday 14 February 2009

Here Be Dragons

I think it's a shame in some ways, that the general human populace has lost interest in our universe.
By which I mean, the rest of it, the stuff beyond our atmosphere.

Back in the 1960s, I think everyone truly believed we'd soon by on Mars. Because we'd made it to the Moon. The fact that going to Mars is a whole different ball game to going to the Moon seems to have passed everyone by. It's like comparing crossing the Irish sea in a yacht to crossing the Atlantic in a yacht.

It was exciting. We'd got off our rock. Not only that, people were now seeing close up photographs of Mars and Venus. We'd sent probes, we were seeing real pictures. We had sketch maps of Mars before, but they'd been drawn using the telescope. Now we had maps constructed from close range photographs. The Moon, Mars, well, it was all space, we were up there now, next stop the Andromeda Galaxy.
We all got too excited and carried away too quickly.

But it will come, of course. Only now it doesn't seem so exciting. We seem to be more realistic about now, perhaps a bit too realistic. And sadly, people don't seem to realise any longer just how fast our expansion of our world is moving.

One looks at maps of Earth in the eighteenth century. No one really had a clue what the west coast of America north of California looked like and what sort of land, if any at all lurked around the South Pole was anyone's guess. And where did the Nile rise? No one knew. They just put pictures of dragons and mermaids in the blank spaces.

And of course, our knowledge of our star system is still a bit like that. Up until recently, we've been able to name the larger objects orbitting quite close to us, but only recently have we really known much of what these places were like. The Moons of Saturn have entered the human kingdom now, because we don't just know they're there, we have pictures. And maps. Not very good ones yet, but in time they'll get better.

And I guess we're more realistic. We've reflected a little on how big space is. My guess is by 2200,the Moon will have several thriving cities, Mars will be the new California and even Venus will be part of the human culture, albeit maybe only just opening up to settlement above and beyond scientific bases. The regular human sphere will have expanded, it's boundaries will no longer be this sphere, but the asteroid belt. And perhaps we'll be starting to consider the first manned missions to the Gas Giants. And by this time, of course, the moons of every gas Giant will all of them have been as painstakingly mapped as our Moon is today.

But of course, we'll still be looking out, even then, knowing we still, even then, have barely touched the Sun's realm.

Because over the last couple of decades, our knowledge on that has changed. Our perception of it has changed, because our probes have gone so much further. And our theories too.

When I was a child, we were taught that after Neptune was the ninth planet, at the edge of the solar system, 'The edge of the sun's Kingdom', they taught us it was. A bit of an odd planet, because though beyond the Gas giants, it wasn't very big. Perhaps as big as our Moon. And beyond that, comets. No one really knew quite where they came from, but somewhere out there, following their strange orbits, out to the edges, then back in. And then....?

Nothing till Proxima Centauri, 4.2 light years away. And really, there wasn't much more to say than that. And what did we know of other stars? Sometimes how far away they were. How big, what sort of composition, how old they were likely to be. But that was pretty much it.

That has radically changed now. Because we know so much more, not only about this system, but about ALL systems. We can see so much more of this star's domain, but also see things about other stars that tell us things aqbout this one.

Firstly, we've brought a whole now region of the solar system into our knowledge. We had guessed it was there for a long time, but now our vision can see into it. The Kuiper belt and the scattered disc. This swathe of space stretches out about four times the distance from the Sun to the edge of Neptune's orbit. And we now know that Pluto isn't an oddity, a strange planet at the edge of the sun's kingdom, it is the NEAREST of several similar bodies, dwarf planets, that live in the Kuiper belt. We know of four, and one of those is bigger than Pluto. There are likely to be more. One could say it's a bit like the asteroid belt, only it's much, much bigger and the objects in it are much, much, bigger. Bigger than asteroids, but smaller than planets. Hence, dwarf planets. And Pluto is just one of them.

None of this was known when I was a child.

And beyond that, we now suspect we actually come to a real edge, a border region where there is actually a kind of wall, a zone called the heliopause. This is caused by moving outside the direct reaches of the Sun's gravity into the galaxy outside. Because everything on one side is pulled by the Sun and carried with it, everything outside can escape. So there is likely to be a sort of solar windbreak effect. We can actually see this in some neighbouring stars, so we can expect to see it with our own. Again, this is all new knowledge. Of course, we can't as yet confirm this by direct observation in our own system, but it's only a matter of time.

But it's the beyond that we're really starting to open up to our vision. Beyond lies a vast outer circle, perhaps stretching out a quarter to half a light year in radius.
It was first conceived of decades ago and christened the Oort cloud. The vast region where comets spend most of their time when not on their occasional sojourns into our bit of the solar system. Here was the place comets spent most of their time.
We still can't see this region and so it is still all pure speculation, but we've got some more interesting theories.

The first part, is that since the early nineties, we've started to split that disc into two. A much smaller inner disc, perhaps less than ten percent of the Oort cloud where the vast majority of the comets come from called the Hills cloud. The edge, for all practical purposes of the Sun's realm. With the Oort cloud itself being home only to a few unusual comets long range comets, irregular visitors to our tiny region of space.
This means that we can expect, if this is so, to one day in the not too distant future actually have photographs of the home turf of the comets. It must surely be an interesting region of space, unlike anything we've conceived of up till now. A kind of vast debris belt, formed of matter hanging on at the outskirts of Sol, like moths circling a lamp. The Hills cloud is something our probes and our telescopes will see into soon. The Oort cloud may well have to wait a longer time.

But the more interesting possibility, is what several scientists think may lie beyond the Oort cloud. And if it does, it answers a lot of questions.


Myself, I'm actually reasonably convinced by the Nemesis hypothesis. I expect us to identify Nemesis in the next decade or two. It's something our knowledge once didn't expect, the very fact that the theory exists, is a product of knowledge only accumulated in my lifetime. And that's why I find the concept so exciting.

Firstly, the fact is that binary systems, or even threesome star systems, are not uncommon. Stars that orbit in pairs. Stars with connected gravity. They move together. Sirius is one. We see one star, but in fact it is two, very close to eachother. The travel together. In fact, it seems that stars on their own without at least one companion star, are the exception, not the norm.
Planets too. We once thought they could only exist in stars that lacked a companion star. Now we know that not to be so. Part of the reason we thought that, was because we believed our on star to be a solitary star. But several of the planets we have identified in the last decade or so as possessing planets, have been binary stars.

So apart from the fact that this star system is NOT a binary star system- a system like this could exist in orbit around one member of a binary star system. We know that much.

But then of course, we learned something else in the eighties. We learned that the dinosaurs were extincted by a meteorite, maybe fragments of a comet. Not only that, mass extinctions are a regular feature of life on earth. Not so often that life hasn't otherwise got along fine. But often enough to radically change the flora and fauna at periodic intervals.
How often?
Well, roughly every twenty six million years. It's pretty much that precise. Sometimes it's clearly greater than others. Sometimes we're lucky, we only get a bit of debris. But other times, we get a huge downpour of debris. Consensus is, something seems to disrupt the paths of comets by slicing through the Oort cloud every twenty six million years.
And one lead theory is- the Sun has a companion that we can't see. Or haven't seen.

It's always there, but every twenty six million years, it gets too close. Don't worry, we have another thirteen million years.

A red dwarf companion to the Sun fits the bill. If it exists, then it is about half a light year to a light year distant.
So why haven't we seen it?
The suggestion is, we have. But we don't know it. That it is there. But how can we not have seen it when it's so near?

Well, a star's brightness doesn't tell us how near a star is. Sirius is bright, because it's nearby. Proxima Centauri is nearer still, but you can't see it with the naked eye. It's a fairly unremarkable star, our nearest known neighbour. We estimate star distance by seeing if they move relative to us and by how much. They nearer they are to us, the more they appear to move, basically. So we can actually estimate to an amazing degree of accuracy how far all our nearest neighbours are to us.

There could be a red dwarf we've listed as being very far away. Very far away, but relatively bright. We've listed it as far away, because it doesn't appear to move much. But in this case, we're wrong. It doesn't appear to move, because it is moving with the Sun. Yes, it orbits the sun once every twenty six million years, but in terms of time as we know it on a day to day level, it pretty much holds the same position with regard to the sun and will hold it's position in the sky with far greater constancy than any other nearby star.
If Nemesis exists, and it is a red dwarf, than there is no way it isn't already in our star catalogues. It's there amongst the numerous lists of red dwarfs our telescopes have seen and marked as too far away to be of much interest. Just another red dwarf with a catalogue number.

I find the idea exciting, because it stands a good chance of being true. And it's a fascinating tieing up of unanswered questions. The dinosaurs extincted because the Sun is part of a binary system. But the idea that we ourselves are part of a star system of the type we once thought COULDN'T have planets is quite a turnaround in human knowledge.

I actually do find it quite exciting, in a way. The idea that really, in terms of our star and mapping out the domain of our own star, we're still at the 'Here be dragons stage'. There's a vast realm out there to discover, the Empire of Sol, our star.

And that's before we even start to think about Sirius and Proxima Centauri.

Note: I've tried this out at Crushed's holiday home. To see what it looked like. I'm actually not UNimpressed


Anonymous said...

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Very nice my dear!


Anonymous said...

Crushed, This just isn't the future I expected to find when I got here! It's not good enough. I guess I feel ripped off.

It's like someone slipped in a diversion and we ended up in the boonies.

Where is my robot housemaid? May washer/drier/ironer? Unlimited clean fusion power? The slimming pill? The flying car? Holidays in space? Sub orbital transcontinental flights and all that stuff?

What happened to the nice shiny old future? Why did I get this naff worn out one full of crooks, nutters trying to blow the rest of us up, or wanting to go live in the stone age instead?

Can I do it over?

Where did the dream go?

Anonymous said...

Don't you think our attentions shifted inwards? From the 80s, our scientific focus became much more biology-oriented. Probably because advances in those fields were coming more rapidly than in physics, or whatever branch of science deals with space travel.

We started looking inwards, into ourselves, and became obsessed instead with changing our own bodies, rather than moving and expanding outwards.

It's kind of interesting that you can sort of map interest in space exploration onto the imperialist age and the cold war. Perhaps political realities were compelling people to look abroad, as it were.

Now we're much more interested in the only things we love: our own bodies. Get rid of the mistakes, improve, shape, design, and that's how we'll progress.

We can stay here.

I don't think there's any cultural will to explore space anymore, so I think technology will be drawn inwards. We've only just started on this so it's got some way to go yet. Something big would have to change for us to be on Venus by 2200. After all, it's still bloody hard to land probes on it.

Anonymous said...

Tin Drummer. I figure, sooner or later, it's either space exploration, or extinction.

We need to be much more spread out to survive a planet killing asteroid, or some fatal solar event. From what I understand something like that is a sure thing.

Maybe just being able to get away from other people might be enough. To be able to do things your own way.

Maybe the Mormons, or the Israelis, or the Saudi royal family might figure their own world would be worth having...

Anonymous said...

I agree on the extinction bit, Moggs. But I also think, in an old style romantic way, that exploration is what we humans do best. Put a baby down somewhere and it will crawl off to see what it can find. We have this amazing desire to learn about the world and the universe and we should be going for it! Expanding, spreading our wings. It's what we do.

Anonymous said...

Tin Drummer, Absolutely.