When size matters (100 years, Part VI)

Neat process diagrams of metabolism always gave the impression of some orderly molecular conveyer belt, but the truth was, life was powered by nothing at the deepest level but a sequence of chance collisions. (1)

Zoom down far enough (but not too far – or the Aladdin merchant might complain) and all matter is just a soup of interacting molecules. Chance encounters and interactions, but with a high enough probability to happen. In essence, life is a series of molecular interactions (that, in turn, are atomic interactions and so on and so on…)

The form of the cellular framework of plants and also of animals depends, in its essential features, upon the forces of molecular physics. (2)

Quite often, we can ignore those small-scale phenomena, but only as long as the system we are describing is large enough. As in physics, in biological systems size does matter (*insert ambiguous joke here*). We have to adapt the governing physical rules depending on the scale that we are observing. Do we consider every quantum-biological detail, can we use a cell as the smallest entity or even use whole organisms as the smallest functional entity?

Life has a range of magnitude narrow indeed compared to with which physical science deals; but it is wide enough to include three such discrepant conditions as those in which a man, an insect and a bacillus have their being and play their several roles. Man is ruled by gravitation, and rests on mother earth. A water-beetle finds the surface of a pool a matter of life and death, a perilous entanglement or an indispensable support. In a third world, where the bacillus lives, gravitation is forgotten, and the viscosity of the liquid, the resistance defined by Stoke’s law, the molecular shocks of the Brownian movement, doubtless also the electric charges of the ionised medium, make up the physical environment and have their potent and immediate influence on the organism. (3)

Observing life at the smallest scales (by which I mean cells and unicellular organisms) at least has the advantage the rules driving form and structure can, at least in many cases, be considered relatively simple: surface-tension.

In either case, we shall find a great tendency in small organisms to assume either the spherical form or other simple forms related to ordinary inanimate surface-tension phenomena, which forms do not recur in the external morphology of large animals. (4)

While on the topic of size, as many things in the universe: size is relative. I have noticed in conversations with colleagues and supervisors that what is considered small or large, definitely depends on the point of perspective (and often: whatever the size is that that person typically studies). I could assume that for a zoologist, a mouse is a small animal, but tell a microscopist they have to image an area of 1 mm² and the task seems monstrous. For a particle physicist, a micrometre is immense, but for an astrophysicist, the sun is actually quite close.

We are accustomed to think of magnitude as a purely relative matter. We call a thing big or little with reference with what it is wont to be, as when we speak of a small elephant of a large rat; and we are apt accordingly to suppose that size makes no other or more essential difference. (5)

Undoubtedly philosophers are in the right when they tell us that nothing is great and little otherwise than by comparison. (6)

There is no absolute scale of size in the Universe, for it is boundless towards the great and also boundless towards the small. (5)

That’s the amazing thing about science: we strive to understand the universe on all scales. The universe is mindblowing in its size, in both directions on the length scale.

We distinguish, and can never help distinguishing, between the things which are at our own scale and order, to which our minds are accustomed and our senses attuned, and those remote phenomena which ordinary standards fail to measure, in regions where there is no habitable city for the mind of man. (7)

Good thing we have scientists, amazing minds, capable of studying, visualising and even starting to understand the universe on all its scales…

Ms48534_13
My mind might be boggled, but here’s a man that looks like his mind contains the universe. (D’Arcy in his 80s)

(1) Permutation city – Greg Egan, p. 67

(2) Wildeman

(3) On Growth and Form – p. 77

(4) On Growth and Form – p. 57

(5) Gulliver

(6) On Growth and Form – p. 24

(7) On Growth and Form – p. 21

(3-4, 6-7) from D’Arcy Thompson, On Growth and Form,  Cambridge university press, 1992 (unaltered from 1942 edition)

To the horizon, and beyond!

Both of my subscription magazines – *I’m so sophisticated* – had articles about the advances in space exploration last week (though by now it’s more two weeks ago). It’s been a while since I read so much of my subscription magazines, I usually leaf through most of it – *gone sophistication* – because I’m stuck in the illusion that I don’t have any time.

Which is ridiculous, check my Netflix record.

But nothing better to bring me back into good reading habits than some good ol’ articles about space. And nothing better to get me back to blogging about science subjects again as well. Because let’s be honest, it’s quite difficult to get me to shut up about space.

It had been quiet for a while, in the space news column of your daily/weekly/monthly newspaper. Apart from some back-and-forth travel to and from ISS and the occasional news blast when a countryman was sent up (for me this was Frank De Winne and more recently Tim Peake). But in the last few months, the interest for space has rekindled. Whether it is due to the recent abundance of space movies (Interstellar, Gravity, The Martian), astronomy breakthroughs (LIGA) or NASA’s call for astronauts last year (18400 applicants!), I do not know, but astrosciences has been back in the press.

The most recent exciting news has probably been the discovery of Proxima Centauri b (from now on referred to as PCb). PCb orbit’s the sun’s nearest neighbour, Proxima Centauri, making it close enough to have a very laggy conversation with potential inhabitants of the planet. The possibilities scream to the imagination. It might have an atmosphere. It might have water. It is only 4 light years away. It orbits the Goldilocks zone of Proxima Centauri; 7 million km from it (which is about 1/20 of earth’s to its sun) . It has an estimated weight of 1.3 to 3 that of earth. It is  presumed to be rocky. It has an orbit of 11 days, making me 875 orbits of age. (Read more about PCb in the original article.)

Okay, I realise, and so does the research community, that we barely know anything about PCb. But that’s not really the issue. The possibilities are the issue. It’s closeness, it’s “just right”-ness and its promise of potential life forms are enough to get us all excited. And excitement is quite an understatement, you can be sure of that.

Luckily for us, a new form of space exploration has taken place. A first change is the commercialisation of space travel. It’s no longer just for governments to prove their superiority by making it to a certain satellite first. Several visionaries who happen to be billionaires are investing in space travel. For industry and the commercial sector, such as telecommunication, but also towards tourism. This helps to lower the cost of space travel, making “a trip to orbit” more than a very vivid dream.

Luckily for us, we have an Elon Musk, who dreams of a self-sufficient colony on Mars. Luckily for us, we have a Richard Branson, who wants to make space tourism reality. Luckily for us, we have a Jeff Bezos, who thinks that eventually there will be thousands of satellites in orbit employing millions of people. This idea of “great inversion” could allow us to change the earth into one giant nature reserve.

Luckily for us, the billionaires of the world – or at least some of them – are not only driven by profit but also by curiosity.

elon-musk-the-simpsons-tapped-out
Elon Musk all packed up for his move to Mars. (The Simpsons, in case you hadn’t guessed.)

On the other hand, minaturisation is driving a new way of space exploration. We wouldn’t necessarily need to send enormous, fuel-consuming, costly rockets off to the planets and comets and space we’d like to explore. They can be tiny. Made out of components that are already mass produced. Relatively cheap to make. Of course, I love the idea of still sending humans to space, and I’m quite sure they will continue to do so, but the amount of data and knowledge we can gain from small satellites, such as Planet’s “Doves”, is extremely exciting on its own.

So let’s keep exploring. There is so much out there for us to learn about, and we are making the tools to do it.