And Slaters Go Plop

If you live in the Southern Hemisphere you can look up on any given starry night and just over from the Southern Cross you’ll see a fuzzy patch. It’s called the Large Magellanic Cloud (LMC) and is actually another galaxy quite close to our own Milky Way. To get a sense of size and distance our Milky Way is about 100,000 light-years across and the LMC is about 160,000 light-years away from us but only about 1/10th of the size. Right on our doorstep so to speak.

160,000 light-years is still a long way away though. A light-year is the distance light can travel in a year which equates to about 9,460,730,000,000 kilometres and this LMC is 160,000 of those.

There are different types of stars and they all go through different stages of their lives. Some stars burn up all their fuel and end up collapsing in on themselves at the same time as shedding an ‘outer shell’ and they go nuts burning new materials – these are called Supernovae, you’ve probably heard of them.

One day in 1987 a star in the LMC (previously catalogued as Sk-69 202 but now called SN 1987A) did just this and it was a spectacular sight. Observatories around the world kept an eye on it as it wrecked havoc in slow motion over the next few years.

One thing they noticed was that when the star in the middle brightened the main ring would brighten eight months later and when the star dimmed the ring would, again, dim eight months later. This means that the light that comes directly from the star to our eyes travels a shorter distance than the light that has to go out to the ring and bounce off toward us. Which also means that the ring has a radius of 0.658 light-years (or a diameter of 6,200,000,000,000 km if we’re feeling clever).

Knowing the size of an object is very useful if you want to be able to know the distance to that object. If you know that person is 2m tall and they look very small (this is really measured in angles) you know that they are a long way away.

Astronomers were able to measure the total angle that SN 1987A took up (a radius of 0.808 arcseconds – very small but still useful) and were able to calculate that it is 168,000±3.5% light-years away from us. Which means that what we saw in the skies in 1987 actually happened 168,000 years ago.

I have a theory based on a number of observations and I want to give it a name. My observations are that there are things that lifeforms do to their environments that leave traces that wouldn’t otherwise naturally occur. I propose that we might be able to detect similar effects on other planets and deduce that there are lifeforms at work and that we might, if we are careful and/or very lucky, find evidence of previously unknown lifeforms here on our planet.

I’ve come up with a name for this theory. I’m calling it Intelligent Design.

We can define what ID is and what it isn’t. We can come up with ways we can test hypotheses. If we find evidence that points towards (or away from) an example of intelligent design we can publish papers in reputable scientific journals. When we find gaps in scientific knowledge in other areas we won’t even think about using this as an argument for Intelligent Design – we’ll have to come up with evidence that points toward our theories and not just away from others.

Unfortunately there are some people who are currently misusing the label of Intelligent Design and they will have to go back to using the old term for their beliefs: creationism. If they have some useful contributions to make they’re more than welcome to join in as they are for any of the other sciences but, just like in the other sciences, they are going to have to leave their non-science behind at the door.

Right, now that that’s dealt with. Onwards and upwards!

[edit: Over at NeuroLogicia, Dr Steven Novella clearly hasn't been informed of the recent changes I've made to the term 'Intelligent Design' but he provides a fairly lucid account of why the proponents of the old term weren't being particularly scientific in their approach that's well worth a read.]

Goodbye and thank you.

Here’s a message from him from last December after his 90th birthday:

Ever since I was young my mind reeled when I tried to comprehend the vastness of our universe and all that is in it. I’ve since realised that it is impossible to truly comprehend these things and that this is a limitation of the bodies and minds we find ourselves in.

However if you, like me, are fascinated by the night sky and you want to get a better understanding of “not only what we know but how we know what we know” then you won’t find a better podcast than the Astronomy Cast.

If I were an alien I’d give it three thumbs up. Check it out.

Like me, you probably wonder from time to time whether you can eat the moon.

I have some bad news; you can’t, even with your friends helping you. Let’s do the figures:

The moon is bigger than it looks (this is because it’s far away) and it weighs in at about 73,477,000,000,000,000,000,000 kg. Contrary to popular opinion it’s made of rock, not cheese (and a half moon is not, in fact, half the size). The fact that it is made of rock is a spanner in the works because it considerably reduces the amount a person can eat in a day. If you want to eat it you are going to have to powder the rock first and then eat it along with other food.

Still, this is a fairly simple equation and we have all the numbers: the weight of the moon divided by the amount you can eat per day gives you how many days it will take to eat the moon.

So, let’s assume that you can eat two powdered tablespoons per meal and we’ll assume that two tablespoons of powdered rock weighs a tidy 50 grams. That leaves us with the weight of the moon divided by 0.150 kg which tells us that it’ll take a person 1,342,045,662,100,456,621,004 years to eat the moon.

If you were to enlist the rest of the world to help you in this enterprise you would be looking at reducing this figure down to a mere 203,271,750,023 years. The age of the universe is 13,700,000,000 years which means you and the rest of the world would be required to exist for 15 times longer than the entire universe has done to date. And to make things worse you’ll probably spend a considerable percentage of this time on the toilet.

(There’s no way to wrap this up in a dignified manner so I’ll just say that perhaps, one day, someone will enter the search string “can you eat the moon?” into Google and I’ll have a little chortle to myself when I see that particular stat in my logs.)

As most of us know, Jesus was bodily resurrected about 2000 years ago. After he was resurrected he ascended up into heaven. But where did he go? Did he wait until everyone had gone home and then came back down again? Did he continue on out into space to an undisclosed location? We just don’t know.

What we can know however, is the vicinity in which he must be. Even travelling at the speed of light (~300,000km per second) he’s still somewhere in our galaxy:

(Obviously, these images are of galaxies other than our own but they’re of a similar size and type. Our galaxy is about 100,000 light years across and we’re located out on one of the spiral arms.)

Carl Sagan died eleven years ago today. His enthusiasm for the universe and everything in it was contagious and he is responsible for the sense of awe I and many, many others feel when we look up at the stars at night.

Our brains are not capable of comprehending the true vastness of space but Carl managed to help us expand our comprehension to the point of vertigo and, with it, and closer understanding of our true standing within the universe.

My thoughts are with his family and I, like many others, wish he was still here.

Oh, and a few years ago I thought it would be cool if there were another habitable planet directly opposite us on the other side of the sun. It could be a similar size and distance from the sun as the earth.

Don’t you just hate that? A month or so ago I had an of idea for a sci-fi storyline but today, as I was continuing my massive 100-hour catchup of all the Skeptic’s Guide to the Universe podcast episodes, I discover that people have already been thinking about it for some time. This kind of thing happens to me a lot and I’m beginning to wonder if I’m inadvertently reading or hearing of ideas that I promptly forget and later “come up with”.

Anyway, I still think it’s a great concept for a story:

I was thinking about how impossible it is to travel to other potentially habitable solar systems (as you do) and considering how absolutely vulnerable we would be if we were to detect a super-large asteroid approaching us. We don’t have the technology yet to safely freeze ourselves for a long-haul flight through space. We don’t know how to produce food in space to sustain a group of people for any length of time. If a sizeable asteroid were to hit we’d have next to no chance of surviving the weeks or months following the impact regardless of where we were located on the planet.

I got to thinking about how we are able to freeze embryos indefinitely and figured that if we had a year or two’s notice of impending doom it might be possible to scramble together as much technology as possible to create thousands of identical small pods containing frozen embryos and fire them in all different directions out into space. I wasn’t sure whether it would be feasible to have the pods contain artificial ‘wombs’ and the materials for a biosphere that are activated upon contact with an alien planet.

Perhaps nurturing humans from frozen embryos is the most feasible option we have at our disposal for human survival across journeys that would take millions of years.

This basic premise gives you a lot of room to play with the psychology of children bought up without human parents, the sheer enormity of discovering that their biological parents have been dead for millions of years, the challenges of seeding life in a new environment, the mechanics of a life support system capable of ‘growing’ and supporting infants, the possibility of regaining contact with other pods.

It would be quite fun to be drawn along with the story only knowing as much as the children know about how they got there and what happened to earth.

Unfortunately I don’t have the skills or inclination to go ahead and turn this into a story but I implore anyone reading this who is a writer of sci-fi to take this concept and turn it into a novel. And please tell me about it! I’d love to read it.

Last week the Phoenix Mars Mission was launched and it’s out there somewhere right now travelling at 16,000 miles per hour and will reach Mars on May 25, 2008 where it will rummage around on the northern icy plains. This video is from the previous Odyssey launch in 2001.