Reason; as the supreme authority in matters of opinion, belief, or conduct

Category: Physics

Fascinating AMA (Ask Me Anything) with Cornell University’s Astronomy team


“I personally am constantly baffled by the size of space, every time you try to compress things by comparing them to smaller things you very quickly get back to a scale you can no longer comprehend. This is why astronomers have to rely so heavily on mathematics, because the scales involved are beyond comprehension by any other means. I study galaxies and to me they are the most beautiful objects in the Universe, they vary so much in shape, size and colour, making up formations that are almost beyond belief. Striving to explain these objects is a fascinating experience.”


Future technology becoming less distinct?

It seems that every technological discipline you care to look at promises to close the gap on science fiction in the coming years. I try to remind myself that the rate of advancement will, it seems, stun as much as the creativity and brilliance of the technologies we see. A ‘perfect lens’ that can image a protein, or an invisibility cloak? We may soon see both.


Carl Sagan’s thoughts on Voyager 1’s Image

Carl Sagan’s thoughts on Voyager 1’s Image

“Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there-on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.”

– Carl Sagan, 1994


A little perspective…

A little perspective…

Carl Sagan once said, in his profound and eloquent thoughts on Voyager 1’s iconic image looking back at Earth, that “There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.” I think his point is exactly the right one to make, the kind made by a man who would not for a second consider passing up an opportunity to champion rationalism. The greatest thinkers seldom do.

Seeing this type of perspective is a good exercise for humans. It helps to thwart that tempting inner feeling that we are somehow special, somehow divine. That dangerous feeling that we will prevail. Below I include a link to an interesting wikipedia page that I think can have the same effect. When you think of the extreme dangers we are ignoring today, that threaten us on a time scale of hundreds of years or less, it is strange to think we will, in all likelihood, never have the chance to pit our collective wit against the myriad of far greater difficulties that lie ahead.


TED talk: Phil Plait: How to defend the Earth from asteroids

TED talk: Phil Plait: How to defend the Earth from asteroids

This TED talk covers some fascinating facts on historic asteroids and discusses the potential dangers they could yet pose. More interesting still, Phil Plait goes on to describe some of the many creative solutions that have surfaced since the discussion began.


“This brings me to the last of the big questions, the future of the human race. If we are the only intelligent beings in the galaxy, we should make sure we survive and continue. But we are entering an increasingly dangerous period of our history. Our population and our use of the finite resources of planet Earth are growing exponentially, along with our technical ability to change the environment for good or ill. But our genetic code still carries selfish and aggressive instincts that were of survival advantage in the past. It will be difficult enough to avoid disaster in the next hundred years, let alone the next thousand or million. Our only chance of long term survival is not to remain inward looking on planet Earth, but to spread out into space.” – Stephen Hawking in his 2008 TED talk.


Titan as enigmatic as Europa…

We have heard a lot about Europa. Locked in Jupiter’s orbit it is one of the smoothest celestial bodies in our solar system. We believe that enveloping an iron core, similar to Earth’s, is a massive ice crust comprised of more than double the water found here at home. Its greatest spectacle is very common knowledge today; that according to the best evidence it seems there may be a vast liquid ocean, perhaps 100km deep, under a shell 30km across. On the list of things I hope to see in my life, footage sent back from the oceans beneath is in competition for top spot.

Amazingly there is almost an even more extraordinary satellite in our solar system – Titan. Reading the details we know about Titan seem to place it closer to the realms of science-fiction than reality, but how often does that seem to be the case. Views of that most awe-striking planet, Saturn, are obscured from Titan’s surface by a dense, orange organonitrogen haze. Overall its atmosphere is mostly nitrogen, but as a strange parallel to our familiar Earth its atmosphere is adorned with clouds of methane and ethane gas. Hidden under its orange haze, Titan is only revealing its mysteries very slowly. It may be that these clouds are part of a cycle similar to that of water on Earth; including seasons, rain, and resulting rivers and seas. Certainly we know that there are dunes shaped by wind, and pictures of these can be seen on the Wikipedia page I include below. Confirming the presence of Titan’s stable bodies of liquid has been a major focus as they mark the first observed aside from our own. Radar analysis of one of Titan’s polar regions in 2006, by the Cassini spacecraft, revealed many vast lakes, seas and tributary systems. Intriguingly the lakes analysed only varied in height by 3mm at their surface, suggesting either that the winds in this region were low, or that the pools are filled with a very viscous fluid. Similar to Europa, under this strange world above, again it is thought that liquid oceans are hidden within. The vague impression we have of Titan – a cold and mysterious world tantalisingly rich with organic molecules, along with liquid bodies, and perhaps a hidden ocean yet to be confirmed – has meant that it has been studied feverishly since Voyager 1 gave us our first real glimpse in 1979. There are plans to land a probe in one of its polar lakes (images of which can also be seen on the page below), but only when the project can win the never ending funding battle at NASA. It just lost out to a mission that plans to send a probe to Jupiter in 2022 to investigate Europa, and two of Jupiter’s other moons, in more detail. Either way, we wait with patient anticipation.



A journey through Hawking’s imagination on life beyond our planet

A journey through Hawking’s imagination on life beyond our planet

“…My name is Stephen Hawking; physicist, cosmologist, and something of a dreamer”

‘Into the universe with Stephen Hawking’, the 2010 series communicating the mesmerising insights of one our greatest living thinkers, is a journey through those features of the universe that I think we all consider the most compelling, the most captivating. In this episode he discusses alien life; what might these organisms be like? In what environments could they exist? Would they necessarily require the conditions that have led to the spectacle of life we see on earth? And, with undertones of his famous comments on our own survival hopes, what traits might make for a successful civilisation?


The cost of travel

Traveling by train requires a similar amount of energy per distance as that required of a bicycle, per person. The typical measure of transport efficiency is energy per unit distance; per passenger. This is usually expressed as Mega Joules per passenger kilometre (MJ/passenger-km). As a very rough guide walking might take around 0.78 MJ/passenger-km. Cycling slowly, at around 16 km/h, say, would require 0.11 MJ/passenger-km – let’s assume the determined commuter will be demanding double that. Working to those assumptions; locomotion by train, in fact for freight as well as for people, has remarkably high efficiency. The average train might require somewhere below 0.6 MJ/passenger-km, and newer trains are quite exceptionally efficient: When full, the trains in Basel require 0.085 MJ/passenger-km. The East Japanese Railway manages 0.35.

Simply for a little perspective the average car might demand two or three MJ/passenger-km; passenger aircraft around 1.4 MJ/passenger-km. No satisfaction can be taken, however, from the lower values of any of the modes of transport mentioned here because, whether fossil fuel or largely non-nuclear derived electricity, the source of energy is just as harmful for each… except arguably the humble bicycle, of course. Just to mention in passing, as if you couldn’t guess yourself, helicopters are among the least efficient.

TED talk: Adam Savage: How simple ideas lead to scientific discoveries

TED talk: Adam Savage: How simple ideas lead to scientific discoveries

One of the most pleasing aspects of science, and of human contemplation in general, is how creative and innovative solutions to apparently unsurpassable obstacles seem to reliably surface as time passes. The genius that is there to be seen in any field you happen to turn your eyes to is always astounding. From the proposed use of salts as coolants in atmospheric pressure nuclear reactors to the sky crane that lowered Curiosity onto Mars; for the open minded thinkers there may always come along a solution that fits Einstein’s premise: that “Any idea that does not at first seem insane, is doomed to fail.”

In this seminal TED talk Adam Savage captures the essence of such innovative brilliance as he relays some of the most creative and exceptional work of some of the greatest minds to have been recognized for their genius.