Today there was an incredibly interesting presentation by Jaymie Matthews on exoplanets, stellar formation and the results of the MOST satellite which has been running for 7 years and was Canada’s first ‘solo’ satellite launch in 30 years. Everything that Jaymie talked about was fascinating but there was one point that I really latched on to which was the currently accepted model for stellar and planetary formation known as nebular theory.

I’m sure you’re all aware that we think that stars and planets are formed by condensing nebulae but it would be a shame to know this and not know exactly why because it’s very very cool and will give you a warm and fuzzy physics feeling inside.

We start with a star-forming nebula, a very large body of dust and assorted elements drifting through space and spinning slowly as it goes, this cloud is mostly made up of hydrogen but there are some heavier elements as well (if it helps you to visualize it you can think of it as a sphere of dust spread out over a huge area). There is a point somewhere in this body called the center of mass and the nebula acts as if all the particles are being pulled towards this spot by gravity; as dust is pulled into the center of the rotating cloud the nebula becomes smaller causing the speed of rotation to increase just like a figure skater pulling their arms inward as they spin.

At the center of the cloud intense pressure starts the hydrogen fusion reaction that will form the star; as the speed of rotation increases the centrifugal force flings particles near the 'equator’ further away from the star and eventually the nebula becomes a huge rotating disk. The elements at the end of the disk are mostly lighter gases such as hydrogen and the heavier metals are closer to the sun where it is still hot enough for the metal to be in gaseous form. Eventually some of the metal cools and solidifies as it orbits around the star and soon these metallic lumps attracts other heavy elements from the surrounding disk, as they grow in size they 'sweep’ up some of the elements in the disk to form planets and carve out their orbits.

The disk also helps explain why planets that are closer to the sun are denser and contain more minerals than the gas giants further out in the disk: the elements move outward in the disk they get colder and colder but since iron and nickel solidify sooner than hydrogen and oxygen rocky planets tend to form closer to the sun and gas giants form in the outer regions of solar systems where it is cold enough for hydrogen, helium and oxygen to condense. Hydrogen may be the most abundant element in the universe but it’s not very massive so often it’s not the ideal seed element to form a planet.

And that, in the very briefest of terms is how solar systems and stars are formed; I swear I’ll get back to space technology soon but some of this astronomy stuff is just way too awesome to pass up!

-Hugh

Jaymie Matthews’s talk is called Where will Avatar 2 be set? The real science behind exoplanets and MOST and it was absolutely one of the most fascinating lectures I’ve been to all year.

As I alluded to on Friday: June 4th was a pretty big deal for the aerospace industry, in fact it’s safe to say that June 4th 2010 was a huge deal for human space flight and for the privatization of the space industry. Let me break it down for you.

SpaceX is a private spaceflight company that specializes in sending commercial satellites in to low earth orbit (LEO) or geosynchronous orbit (GTO) for a variety of purposes including GPS, TV and other satellite based communications. They are owned and operated by Elon Musk, the founder of PayPal, and with the successful launch of the Falcon 9 they are in pole position to become the most dominant force in spaceflight for the next 5-10 years.

The reason that SpaceX is in such a good spot right now is that the Falcon 9 is a masterpiece of aerospace engineering: it can carry 8000kg more cargo to LEO than the space shuttle, ~7x more cargo than the space shuttle can carry to GTO and best of all a fully loaded Falcon 9 launch costs 89% less than a shuttle launch. Put all this together and you get an extremely good deal for anyone wanting to put up a satellite for commercial purposes, it also means that NASA won’t have to beg Russia to use their fleet of Soyuz spacecraft for all future ISS missions after the space shuttle program is retired later this year. In addition, because of the 2 stage design of the rocket the falcon 9 can operate in either “light” or “heavy lift” mode depending on the needs of the mission, this is a far more efficient set up than NASA’s one-size-fits-all approach.

(Falcon 9 in light configuration, heavy has 2 ‘boosters' attached to the side)

The launch itself went off almost flawlessly at 2:45 EST, the launch time was actually delayed a bit due to an engine mishap but the actual launch and orbit was a complete success prompting a lot of cheering at both the CSA and (presumably) the SpaceX mission control. Employees at the space agency were crowding in around whatever screens they could find to watch the launch on the SpaceX webcast; eyes grew wide and people gushed praise as everyone appeared to revert to their inner geek, eager to weigh the pros and cons of the rocket and fantasize about what this launch means for the future of human spaceflight.

At base level this launch shows us that spaceflight can be much more affordable and efficient than it currently is which is good news for the average consumer because it means that it will be cheaper for companies to provide services which require satellites. Falcon 9’s success is also good news for NASA, the CSA and taxpayers because it means that we don’t have to spend quite so much money to send things into space; programs like the James Webb Space Telescope will be easier to maintain and less costly to create. The launch could even mean the creation of a privatized astronaut corps although that is really just wild and tangential speculation on my part.

What’s important is that this is big, this may be the biggest thing to hit our space program since the ISS missions began in 1998 so I am very excited for the future of the Falcon 9 program.

-Hugh

I just want to mention for those of you who missed it that the first test launch of SpaceX’s falcon 9 rocket carrying the dragon module happened today, this will eventually be the first commercially minded manned spacecraft which is a pretty big deal since currently the only way to get astronauts into space is to be a government. More on that later.

If you cast your mind back to my last post about white dwarfs you’ll remember that they’re supported by electron pressure and that smaller stars are heavier than bigger ones, the problem with that mechanic is that electron degeneracy pressure has a finite limit for the mass of the star so if a white dwarf ever exceeds 1.4 solar masses it will simply implode. However, if during the original supernova the core already exceeds this limit (known as the Chandrasekhar limit) then when it collapses its molecules will seperate into individual atoms and the star will be supported by neutron degeneracy pressure under the same Pauli exclusion principle as a white dwarf. The shift between electron degeneracy and neutron degeneracy pressure may not seem like a life altering difference but it actually has huge implications for the structure and properties of the star.

When we’re talking about electron degeneracy pressure we’re describing the force as if it occurs at the surface of the electron’s orbit which means that even though the molecules are packed as close as possible there’s still a lot of empty space between the nuclei of each molecule. Bearing in mind that the volume of a sphere depends on the radius cubed then if we reduce the effective radius by ½ we’re reducing the effective volume by 1/8th! That’s why neutron stars have a higher mass than a white dwarf and an average radius of only 15km, that means that you could fit a neutron star inside the downtown area of most major cities.

The increased density of neutron stars gives it some extremely strange properties; the high pressure causes some neutrons to form boson pairs which are not governed by the pauli exclusion principle. When the bosons form they all crowd into the lowest energy quantum state and form what’s known as a superfluid, eventually they make a sea of superfluidity within the neutron star which further adds to its list of amazing properties. Superfluids have no resistance so when any vortexes, eddies or waves form in the neutron star they will never stop until the star dies, they are also highly magnetic and any particle within the magnetic field when it is created will be locked into their ‘field position’ until the field ceases to exist.

But the best part about neutron stars is their movement: when the star is still in its gaseous form it rotates slowly and with a huge amount of angular momentum. During a supernova where the core shrinks to form a neutron star the angular momentum is conserved so the star has to undergo a huge increase in rotational speed to offset all the mass and volume that is lost, picture the boulder from the Indiana Jones movie suddenly becoming a ball bearing. Just how fast do neutron stars rotate? A typical neutron star 'day’ lasts a few milliseconds.

When all of these properties are put together we’re left with a star that has around twice the mass of our sun with a radius of 15km that performs a full rotation every 3 milliseconds and is spinning an incredibly powerful magnetic field around with it.

That’s way cooler than CERN no matter what David Gross says.

-Hugh

There is no way I’d show you this picture without the high res version, this is an artist’s rendering of a neutron star a few years or decades before it collides with that star and produces a black hole. Around it you can see the magnetic field lines that I’ll tell you about tomorrow.

Alright, back on track with a great day at work and some new insights into the world (universe?) of astro-physics, topic of the day: dwarf stars.

Life at the center of an ‘active’ star is a constant battle between the intermolecular pressure created by the fusion in the star’s core and the inward force of gravity; once the star runs out of fuel the sustaining reaction will fail causing the core to collapse and the outer regions of the star to be flung into space. After collapsing, the core is mostly carbon and nitrogen but there is no a reaction occuring at the center so the question becomes: what supports the star and prevents an implosion that would form a black hole? The answer is quantum mechanics.

When electrons are squeezed as close together as they are in the center of a white dwarf star the Pauli exclusion principle ensures that no two electrons can occupy the same quantum state, this means that as the star gets packed closer together the electrons themselves will provide the pressure needed to stop the star from collapsing as they refuse to touch eachother. Because of this, white dwarfs are extremely dense, they tend to have the mass of our sun contained in the volume of earth! Another peculiar property is that more massive white dwarf stars are actually smaller than lighter ones since the electrons must be closer to provide the extra pressure to fight gravity, this caused quite a bit of head scratching when it was first discovered.

So where do I come into all this? Well it turns out that even though white dwarfs can’t perform radial oscillation they still oscillate in p-mode and many of the other modes that I didn’t bother telling you about; strangely though, while most stars oscillate with periods between 15 minutes to a number of days white dwarfs also show oscillation at frequencies of .002Hz, only 500 seconds, impossibly fast for other driving mechanisms. To determine what causes these vibrations we need to know what elements are inside the star so I’m writing programs that search for oscillating stars in the data produced by the FUSE telescope. Once we have a list of variable stars we’ll be able to analyze the light they produce and determine accurately what is inside them causing these fast vibrations. This is all very exciting to our team since we will be among the first to look into this and it’s quite likely that we’ll discover new variable stars in the process (naming rights?)

Anyway that’s my job at the space agency, I suppose I could refer to myself as an astroseismologist but 'intern’ sits easier on the tongue and it doesn’t prompt the response “Oh cool, so there are earthquakes in space?”.

Tomorrow I’m going to tell you about neutron stars because some of the stuff that they can do will make your head explode

-Hugh

Today I injured my knee and later saw the AC Milan vs. Montreal impact game at the olympic stadium so I am too tired to make a post but tomorrow I will definitely tell you about how white dwarfs work or reveal some interesting new facet of the space agency.

-Hugh

So even though I’ve told you all this cool stuff about the space agency I do actually spend most of my time there working, all this gawking at mars landers and spacewalks happens on my breaks. To be honest, though, my work is very cool and I take that for granted when I get bogged down in the little details of what I’m doing and forget about the big picture so here’s a general idea of what I do at the nerdiest place in Montreal.

A lot of people don’t know or don’t really think about the fact that stars 99% fluid since it’s much easier to think of a star as just a bright ball in the sky that you can wish upon if you see it before any of the other stars. When you take a look at it, the fact that stars are made up of fluid has pretty huge implications and the most important one is that stars wobble just like the droplets of water in that video.

At the center of the star is a huge fusion reaction which heats up the rest of the star, this makes pressure in the star increase and it also ionizes very outer layer of the star (He -> He+ -> He2+). As the outer layer of the star ionizes each atom becomes more positively charged and repels its neighbours more strongly; the increased force has the effect of ‘thinning’ the outer layer of the star since the space between molecules is greater and allows more radiation to pass through it. As you can imagine once all the radiation has passed through the thin outer layer the star has a lot less heat, this heat loss reduces the pressure within the star and de-ionizes the outer layer causing the star to shrink and the outer layer to become more 'opaque’ until enough radiation is trapped inside the star that it can repeat the process. That’s called radial oscillation and eventually the star will lose enough pressure that during a shrink it will simply collapse on itself causing a supernova.

P-mode oscillation, on the other hand is caused by sound waves within the star and causes some very strange wobbling shapes like the one you see below; there can be hundreds of these wobbles within a star all at different frequencies and with differing numbers of nodes and antinodes. In fact our own star has thousands of these modes which gives astronomers a huge headache.

So what’s the effect of all this shrinking and growing and wobbling? Well do you remember the beat phenomenon? It turns out that the oscillations of stars also produce beat frequencies which means that every once in a blue moon stars will just disappear entirely from view for days at a time! This could have wreaked havoc on early maritime navigation if the north star vanished every month, although it might have lead to some pretty interesting superstitions…

The study of solar oscillations helps us learn about the processes that are going on inside stars from the surface all the way to the core and in the case of degenerate stars (remnants from a supernova) they can even help tell us about what conditions were like when the star was healthy. But that’s a post for another day

Anyway this the kind of stuff I’m working on at the space agency, to be specific I work on white dwarf stars which are way cooler than other stars and exhibit some pretty unique and interesting properties from quantum mechanics; stay tuned for some mind blowing stuff about white dwarfs and neutron stars in the near future.

-Hugh

Sorry I didn’t keep to my schedule.

On friday I got to see my co-worker present some results from the reasearch he’s doing for his thesis on zeolytes, known as molecular channeled structures they are basically sieves on the molecular level and are used in many oil refining processes to separate chemicals. My co-worker will be presenting his work to the Weizmann institute in Israel in a couple of days so in the off chance that people who aren’t my friends on Facebook read this thing I’m not going to tell you about his work until then.

I was embarrassed on Friday when someone told me that the Phoenix lander had discovered that there is ice on Mars back in 2008 and I realized that I’d not heard anything about it even though it’s obviously a huge discovery; after my face had stopped turning red we had a very interesting conversation about the implications of this discovery which I would like to share with you. It turns out that the phoenix lander was tasked with searching for ‘surface ice’ which is ice that scientists predicted to be buried a few inches below the surface of the planet in large swathes of the polar regions, this ice is important because it would help to solidify the theory that mars once had extremely vast oceans in the polar regions.

The news that the lander had discovered surface water was extremely well received by the scientific community not only because it lends weight to the theory but also because it will make it a lot easier for us to pinpoint more water pockets on the surface of the planet now that we know what to look for.

(This is actually a picture of what Mars would look like if it still had its water)

The thing is, we have the same sort of surface water here on Earth in our own polar regions and we can tell where it is because the presence of surface water produces distinct geological features which can be seen from aerial photographs. Therefore if these features are present on mars then there is a very good chance that surface water is present in the same area, in fact, right now in scientific bureaus around the world there are geologists looking at pictures of mars and trying to identify the features which indicate the presence of surface water. The guy I was talking to described the process as being a tedious visual comparison between aerial photos from Mars and from Earth but he hopes that eventually we’ll be able to adapt facial recognition software to search photos of mars for spots with a high probability of ice hidden below the soil.

The best part is that once we get a large list of surface water 'suspect sites’ either by straining our eyes or using computer programs we can replicate the ’Bomb the moon’ experiment on Mars using the satellites orbiting the planet or some other space telescopes to perform a spectroscopic analysis of the impact clouds and check for water. The mystery of where the oceans on Mars have gone is one of the most interesting and solvable questions in our solar system and with results like this and projects like the CSA’s upcoming arctic expedition to learn more about surface water formations it seems like we might be closing in on the answer.

-Hugh 

Today I got a little glimpse into the depth of planning required for robotic operations that happen aboard the ISS, it was a fascinating insight into the ludicrous amount of work that goes into pre-flight testing and “sub-nominal circumstance simulation” (meaning “What are we going to do when shit hits the fan?”) so I thought it would be a good subject for today’s post.

When we think of CANADARM2 we think of a gigantic space arm which moves extremely heavy objects around the space station with ease; we don’t think about the fact that the arm only runs on about 1200 Watts or that when you’ve got such limited power it’s very important to make sure that you are never in a position where the arm has so much momentum that it can’t be stopped before it hits a structure. In fact there’s an entire team of people dedicated to running through sub-nominal simulations and figuring out what’s the maximum speed at which the astronauts can move the arm at different points during the flight, not to mention the optimal path that the arm should take in the first place.

Another important concern is how much force it takes to break the arm; in a seriously “sub-nominal” circumstance the arm is able to lock down and completely cease movement, absorbing all of the kinetic energy by flexing the graphite composite tubing that makes up the shaft of the arm, this means that the team running simulations on the arm is also tasked with finding out what’s the maximum speed that the arm can go before a lockdown would result in an expensive and probably deadly system failure.

Thankfully for this team their job usually consists of setting limits and precautions to the flight which is challenging in and of itself but not particularly stressful since they are given a lot of time to come up with a suitable flight path and since operations go according to plan most of the time the team usually spends the mission watching the big screen and sipping coffee. Unfortunately, missions do go wrong and when they do the planning team is given only hours to come up with a new flight plan or an addition to the flight plan that is still within the margins of safety and manages to circumvent whatever problem has arisen, this is crunch time for the team and there is absolutely no room for error in their work.

It’s important to note that there’s a lot more going on during a space operation than meets the eye; the team I just described does not usually have more than 5-10 people working on it and there are over 500 others involved in different aspects of every space flight in back-rooms all over the world. The level of precision and the attention to detail that is demanded by this profession is truly astounding as is the capacity of these people to predict and account for the screw ups that eventually happen.

On another note I have just found out that the guy I work across from made it to the top 12 in Canada’s last astronaut recruitment campaign, meaning that he is in the 99.8th percentile of the Canadian astronaut candidacy pool which is a seriously amazing accomplishment. Tomorrow I shall interrogate him.

-Hugh

About 2 years ago the Canadian Space Agency announced that they were looking for two more astronauts to add to ‘team Canada’ and after a grueling process that lasted over a year they whittled down their list of over 5300 candidates to two: Jeremy Hansen and David Saint-Jaques. Astronaut training and selection is notoriously difficult but it wasn’t until this campaign that the rest of us got a good look at just how intense the process really is.

The first cut of the campaign eliminated all but 100 would be spacefarers just by examination of the materials supplied during the application process, this cut was followed by a series of medical tests and then individual interviews with each candidate. After this stage was completed and more cuts were made they began to put the astronauts’ noses to the grindstone with a series of increasingly difficult challenges. The process began with knowledge and fitness testing across a wide range of subjects and activities; astronauts were expected to show excellence in their field and quickness of mind as well as physical fitness on the level of semi professional athletes.

Once these basic requirements had been tested and more cuts had been made the astronauts were given more involved trials and exercises that would test creativity, problem solving abilities, stress response and teamwork; many tests late in the campaign involved hazardous environments and timed objectives, some tests were even given while the astronauts were unaware that they were being tested.

In the video above you’ll see the astronauts performing these tests which involved plugging leaks in a room rapidly filling with water, fighting spontaneous fires, performing helicopter crash recoveries and locating and disposing of hazardous materials. The tests were designed to be as physically and mentally challenging as possible and the tests drew on training programs and expertise from every emergency response occupation in the book in order to ensure that the final two astronauts would be people who could be called upon to efficiently deal with anything and everything that lay ahead of them.

I wanted to post this because the testing process is really cool and because 'what it takes’ is a pretty grey area in most people’s minds where astronauts are concerned and it’s interesting to find out that what it actually takes is proficiency at pretty much everything.

Later on I’ll tell you what it was like when they actually started training.