Posts Tagged‘observation’

Spinning Close to a Star.

Whenever I think of a tidally locked planet, like say Mercury, the only image that comes to mind is one that is barren of all life. You see for tidally locked systems the face of the smaller body is always pointing towards the larger one, like our Moon is towards Earth. For planets and suns this means that the surface of the tidally locked planet would typically turn into an inferno with the other side becoming a frigid wasteland, both devoid of any kind of life. However new research shows that these planets might not be the lifeless rocks we once thought them to be and, in fact, they could be far more Earthlike than we previously thought.

PlanetWREEL2

Scientists have long theorized that planets of this nature could potentially harbour a habitable band around their terminator, a tenuous strip that exists between the freezing depths of the cold side and the furnace of the hot side. Such a planet wouldn’t have the day/night cycles that we’re accustomed to however and it would be likely that any life that evolved there would have adapted to the permanent daylight. There’d also be some pretty extreme winds to contend with as well due to the massive differences in temperature although how severe they were would be heavily dependent on the thickness of the atmosphere. Still it’s possible that that little band could harbor all sorts of life, despite the conditions that bookended its environment.

However there’s another theory that states that these kinds of planets might not be the one sided hotbeds that we initially thought them to be. Instead of being fully tidally locked with their parent star planets like this might actually still rotate thanks to the heavy winds that would whip across their surface. These winds would push against the planets surface, giving it enough rotation to overcome the tidal locking caused by the parent star’s gravity. There’s actually an example of this within our own solar system: Venus which by all rights should be tidally locked to our Sun. However it’s not although it’s extremely long days and retrograde rotation (it spins the opposite way to every other planet) hints at the fact that its rotation is caused by forces that a different to that from every other planet.

Counterintuitively it seems that Venus’ extremely thick atmosphere might be working against it in this regard as the modelling done shows that planets with thinner atmospheres would actually experience a higher rotational rate. This means that an Earthlike planet that should be tidally locked would likely not be and the resulting motion would be enough to make the majority of the planet habitable. In turn this would mean that many of the supposedly tidally locked planets we’ve discovered could actually turn out to be habitable candidates.

Whilst these are just beautiful models for now they can hopefully drive the requirements for future craft and observatories here on Earth that will be able to look for the signatures of these kinds of planets. Considering that our detection methods are currently skewed towards detecting planets that are close to their parent stars this will mean a much greater hit rate for habitable candidates, providing a wealth of data to validate against. Whether we’ll be able to get some direct observations of such planets within the next century or more is a question we won’t likely have an answer to soon, but hopefully one day we will.

We Live in an Inflationary Universe.

The quest to understand our origins is an innate part of our psyche as humans. You can see evidence of this stretching as far back as we kept records as our ancestors grappled with the idea of where they originated from, whether it was a (relatively) simple question of lineage or the larger question of where we, and all that we know of, came from. Modern science has made incredible leaps in this area, expanding our understanding to show that we live in a universe that is old beyond any of our wildest guesses and is home to more wonders than any could have dreamed of. Still the ultimate question, of where everything began, still puzzles us although as of today we’ve begun to lay down the first few pieces in this puzzle and they’re magnificent.

BICEP2 TwilightYou’re likely familiar with the concept of the Big Bang, the theorized event that gave birth to our universe and marked the beginning of time. However the specifics of what happened during that time are the subject of intense debate among the scientific community and there are many theories that model what may have happened. One of the most popular theories is that during the Big Bang the universe underwent a period of massive inflation in the tiny fractions of a second after it began, expanding faster than the speed of light. There was a lot of indirect evidence to support this (like the fact that our universe is still expanding) but direct proof of this occurring had been elusive.

That was until the telescope picture above, called BICEP-2, caught a picture of something that could only exist if that theory was correct.

Our universe still has remnants of the Big Bang hanging around in something called the Cosmic Microwave Background (CMB). It’s a kind of radiation that’s pretty much uniform not matter which direction you look into, something which is pretty peculiar when you consider just how wide and varied everything else we can observe is. BICEP-2 was searching for something in particular though, a pattern in this radiation that could only have happened should the early universe undergone a period of rapid inflation. The technical term for this is primordial B-mode polarization and was widely believed to have a value of below 0.11 based on previous maps of the CMB. BICEP-2 on the other hand has come in at a 5 sigma confidence level (1 in 3.5 million chance of being random, the gold standard for confirmation in this field of physics) as 0.2, excluding many models and theories that were based on that assumption. It opens up a whole new world of physics and is the first direct proof of the inflationary model.

To understand just how huge of an impact this is going to have on the world of physics you just have to see the reaction of Andrei Linde, one of the first to propose such a model, and his wife Renata Kallosh (also a well renowned theoretical physicist) reacting to the news:

It’s one thing to find proof of something and it’s another thing entirely to show something can not be. This discovery is powerful not because it shows us that a certain model is correct more it has shown us that the widely held belief was in fact wrong and we need to start heading in another direction. Confirmation of this shouldn’t be far off (indeed the team behind the discovery held onto the results for a year to make sure) and with that we’ll enter into a new world scientific debate, one that was so much more informed than before.

 

Myth Confirmed: Ball Lightning is Real.

There’s a lot of observed phenomena in the world which the only evidence we have of it occurring is from numerous first hand accounts. Whilst these can make for interesting stories, potentially leading to scientific theories to explain said phenomena, the plural of anecdote isn’t data and unfortunately that means they’re rarely the subject of rigorous study. However sometimes serendipity strikes and the right people just happen to be in the right place with the right equipment to capture solid proof of a phenomena, solidifying all those anecdotes with a solid scientific narrative.

And today we now have proof that ball lightning exists:

The video might not look like much but it’s a combination of high-speed video (the little ball on the left) and a spectrograph that details the composition of the spectra coming off the light source. This video was made possible by the fact that Chinese researches were at the Qinghai Plateau to observe regular old cloud to ground lightning and just so happened to catch a ball lightning event in action. The spectrograph allowed them to determine the composition of the ball as well and it closely matched that of soil. This is the first supporting evidence we have of the theory that ball lightning is actually vaporized silicon from the soil as the element, when heated, does seem to act an awful lot like ball lightning.

Interestingly though this only gives credence to one reported type of ball lightning as there have been reports of other types, specifically ones that move horizontally and others that don’t touch the ground at all. Considering how long it took us just to get this observation I wouldn’t be holding my breath to see the other types confirmed any time soon but this does open up the possibility of more research being done in the area. If anything it shows that some weird, random phenomena that have been reported elsewhere might be worth investigation, even if its just to confirm or deny that they exist.

Blue Marble 2012.

There’s a couple iconic photographs from space that everyone is familiar with. The most recognizable is probably this one I used a couple years ago during the 40th anniversary celebration of the Apollo missions showing Buzz Aldrin standing on the dusty surface of the moon. A few other notables are ones like Earthrise, The Pale Blue Dot and the STS-1 mission liftoff  (note the white external fuel tank, one of only 2 to have it) but above them all stands the Blue Marble, an incredibly breath taking view of our earth as seen by the Apollo 17 crew on their mission to the moon.

It’s a beautiful photo and one that changed my, and certainly many others, view of the world. I don’t know why I used to think this but before seeing this picture I imagined the world being mostly cloudless, not covered in the swaths of thick cloud that you see in the picture above. It also puts your entire life in perspective, much like the Pale Blue Dot does, knowing that in the end we’re all clinging to this giant water covered rock shooting through space.

Over the years NASA has set about recreating the Blue Marble as technology progressed, mostly just as an aside to one of their many Earth sensing programs. The big difference between the original and these subsequent releases is that the newer ones are composite images, I.E. they’re not a single photograph. You can see this quite clearly in the 2005 version which shows how the Earth would look like if there was no cloud cover, something that’s simply impossible to photograph. The most recent addition to this lineage of whole Earth pictures is the Blue Marble 2012 and it’s quite spectacular:

The original picture is some 8000 x 8000 pixels large (64 megapixels) and gives you an incredible amount of detail. The resolution is high enough for you to be able to pick out topographical details with relative ease and you can even see the shadows that some of the clouds are casting on the ground below them. The original article that was linked to me had a lot of interesting comments (a lot on how the Americas appear to be somewhat distorted) but one that caught my attention was a question about one of the differences between the two pictures.

Why, they asked, is there no thin blue halo in the original picture?

The halo they were referring to is clearly visible if you view the larger version of the new Blue Marble picture and seems distinctly absent in the original. The planet hasn’t radically changed (geologically, at least) in the time between the pictures so the question is a curious one. To figure this out we have to understand the differences in how both these images came to be and in there is where our answer lies.

The original Blue Marble was taken by a single 70mm Hasselblad camera with a 80mm lens at a distance of approximately 45,000KM away from the Earth. The newer version is a composite reconstruction from several images taken by the Suomi NPP satellite which orbits at around 500KM above the Earth’s surface. Disregarding the imaging technology used and the reconstruction techniques on the modern version it becomes apparent that there’s a massive difference in the distance that these pictures were taken. Looking at the halo you’ll notice that it’s quite small in comparison to the size of the Earth so as your distance from Earth increases the smaller that halo will appear. So for the original Blue Marble the halo is pretty much invisible because the resolution of the camera is insufficient to capture it. The newer picture, being much closer and having a higher effective resolution, is able to capture it.

These kinds of images are always fascinating to me, not just for their beauty but also for the story behind what went into creating them. The number of man hours that went into creating something like this that appears so simple is staggering and demonstrates that we, as a species, are capable of great things if we put our minds to it. The Blue Marble 2012 might not become the icon that its predecessor was but its still an awe inspiring image to look at and even more interesting one to contemplate.

Is The X-37B Tracking China’s Efforts in Space?

The USA has always been wary of China’s ambitions in space and I believe it’s mostly for all the wrong reasons. Sure I can understand that the fact that China’s space division is basically a wing of its military might be cause for concern, but the same could be said for the fact that the USA’s Department of Defense’s budget for space exploration exceeds that of NASA’s. Indeed the USA is worried enough about China’s growing power in space and other industries that there’s already been speculation that it could spark another space race. Whilst this would be amazing for a space nut like myself I really wouldn’t wish that kind of tension on the world, especially when the USA is struggling as much as it is right now.

Of course that tension is enough to spark all sorts of other speculation, like for instance the true nature of the mysterious X-37B’s mission. It’s payload bay suggested that it was capable of satellite capture, an attribute shared by it’s bigger cousin the Shuttle, but its previous orbits didn’t put it near anything and it didn’t really have enough delta-v capability to be able to intersect with anything outside a few degrees of its own orbit. However since then there’s been a couple launches and one of them is smack bang in the X-37B’s territory.

The craft in question is none other than China’s Tiangong-1.

Yesterday the BBC ran an article that speculated that the USA was using the X-37B to spy on Tiangong-1. Now initially I dismissed this as pure speculation, there are far easier ways for the USA to spy on a satellite (like using one of their numerous other satellites or ground based dish arrays) than throwing their still experimental craft up in a chase orbit. However checking the orbital information for both Tiangong-1 and the X-37B shows that they do indeed share very similar orbits, varying by only 0.3 of a degree in inclination and having pretty similar apogees and perigees. Figuring this is the future and everything should be a few Google searches away from certainty I set about finding out just how far apart these two satellites actually are to see if   there was some possibility of it being used to spy on China.

To do this I used 2 different tools, the first being n2yo.com a satellite tracking website. This site allows you to input the satellites you want to track and then displays them on a Google map. Once I have that I can then use another tool, this time from findpostcode.com.au which shows me the distance between two points (which thankfully also takes into account the fact the earth isn’t flat). So firstly here’s a picture of the two orbits overlapped:

So as you can see they do indeed share very similar orbits but there does seem to be an awful lot of distance between them. Just how much distance? Well the second picture tells the full story:

Just over 14,000KM which is greater than the diameter of the earth. What this means is that if the X-37B was being used to spy on Tiangong-1 it would have to peer through the earth in order to see it, something which I’m pretty sure it isn’t capable of. Also if you look at the first picture you’ll also notice that Tiangong-1 actually passes over the USA as part of its normal orbital rotation, putting it well within the purview of all the ground observations that they have control of. I’ll note that the distance between Tiangong-1 and the X-37B won’t remain constant, but they will spend a good portion of their lives apart. Enough so that I don’t believe it would be particularly useful for reconnaissance. Additionally unless the USA knew which orbit that Tiangong-1 was going to use (possible, but we’re getting deeper into conspiracy territory here) then technically Tiangong-1 launched onto the X-37B’s orbit and not the other way around (it has not changed its orbit since the second launch, unlike it did the first time).

Honestly the idea that the USA was using the X-37B was definitely an interesting prospect but in reality there’s really no justification apart from conspiracy theory-esque hand waving. The USA has far better tools at their disposal to spy on China’s fledgling space industry than a single run experimental craft that’s only on its second flight. The orbits also put them at a fair distance apart for a good chunk of the time (as far as I can tell, at least) as well making it even less likely that the X-37B is being used for spying. Still it was an interesting idea to investigate, as is most things to do with the ever mysterious X-37B.