Posts Tagged‘universe’

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.

 

Nomad Planets: Our Intergalactic Truck Stops.

In the short time that I’ve been enamoured with all things space our understanding of the universe has changed significantly. Just a few years ago we had no idea how common multi-planet systems like our own were but today we know that a star is far more likely to have several planets than just a few. At the same time we’ve discovered so many more exoplanets that their discovery is now just routine and the count has tripled from the couple hundred to well over 600 confirmed discoveries (not including the multitude of current candidates). At the same time our understanding of how planets form has also been called into question and today brings news that may just turn our understanding on its head yet again.

Astronomers at the Kavli Institute for Particle Astrophysics and Cosmology released a paper back in February that detailed a very interesting idea. Using the observable effects of gravity in our galaxy combined with the observable mass (detected via microlensing events) they’ve deduced that there needs to be many more planets than what can be accounted for. What’s really curious about these planets is that they would have formed without a parent star:

But how can this be? Every star can’t have tens of thousands of planets ranging from Pluto-sized to Jupiter-sized. This planetary “excess” actually suggests the existence of planets that were born without a star – nomad planets. These planetary vagabonds somehow went through the planet-forming process in interstellar space, not in the dusty proto-planetary disk surrounding a young star.

This astonishing number was calculated by extrapolating a dozen “microlensing” events of nomad worlds passing in front of distant stars. When these nomad planets drifted in front of distant stars, they briefly focused the starlight with their gravity, causing the star to brighten. This brightening was captured by astronomers and the microlensing events could be analysed to reveal the characteristics of the nomad planets.

The idea of planets forming sans a parent star is an interesting one as it turns our current ideas of planet formation on their head. The generally accepted idea of planet formation is that a large accretion disk forms a star first, sweeping away a lot of matter away from it. After that the left over accretion belt begins coalescing into planets, asteroids and other heavenly bodies. Nomad planets then would have formed in smaller accretion disks without the required matter to form a star. If the paper is anything to go by this happens extremely often, to the tune of 100,000 times more often than there are stars in our galaxy.

Such planets are incredibly difficult to detect as we have no beacon to observe for wobbles (the radial velocity method). The only way we have to detect them currently is via microlensing and that means that the planet has to pass between us and another star for us to be able to see it. Even with so many planets and stars out there the chances of them all lining up are pretty slim which explains why we haven’t detected any to date. What we have found though are Brown Dwarfs and they’re quite interesting yet again.

Brown Dwarfs are what you’d call failed stars (or over-achieving planets, take your pick) as whilst they’re quite massive, on the order of 13 times the size of Jupiter at minimum, they still don’t have enough mass to ignite and become a fully fledged star. They do however generate quite a bit of heat which they give off as infra-red light. We can detect this quite readily and have identified many of them in the past. What’s intriguing though is that these Brown Dwarfs (or other nomad planets) could be used as stepping stones to the rest of the galaxy.

There’s a couple things that such planets could be used for. We already know that such planets could be used as a gravity slingshot to give current interstellar craft a speed boost en route to their destination. Another highly theoretical use would be to use these planets as refuelling stops if you were using some kind of hydrogen/helium powered craft. Such planets would also make excellent observation posts as they’d be far away from strong sources of light and radio waves, allowing them an extremely clear view of the universe. Indeed nomad planets could be quite the boon for an interstellar civilization, all we need is the technology to access them.

I’m very interested to see where this theory takes us and hopefully we’ll star seeing some nomad candidates popping up in the exoplanet catalogues in the next couple years. We might not yet be able to make use of them but their mere existence would tell us so much about the formation of heavenly bodies in our universe. At the same time it also raises a lot of questions that we haven’t considered before, but that’s the beauty of science.

Piercing The Blazing Glare of Distant Suns.

Staring up at the night sky is one of the most humbling experiences I’ve ever felt. Each of those tiny points of light is a sun burning furiously in a runaway fusion reaction. By comparison I, a mere human, am no more than a tiny fleck in comparison to one of those stars and barely even an atom when compared to the teaming masses of stars that make up that beautiful nightscape. Even more daunting then is the possibility that each of those twinkling stars plays host to a solar system like our own with dozens of planets just waiting for discovery. Our hunt for these planets has brought us hundreds of large gas giants who by the nature have been very easy to detect. Direct imaging of these planets has been nigh on impossible with the precious few we’ve managed to glimpse being extraordinary examples, rather than the rule. That is set to change, however.

Light, you see, is a funny thing. For centuries scientists pondered over the modelling of it, with the two dominant theories describing it as either as a particle or a wave phenomena. Problem is that light didn’t fit neatly into either of the models, requiring complex modelling in order to fit its behaviour into either the particle or wave category. Today many of the properties of light are now explained thanks to Einstein’s theory of wave-particle duality but for a long time one of the most confounding properties of light was that light can interfere with itself. You’ve probably seen this demonstrated to you back in college via the double slit experiment where you get a pattern of light and dark from a single source of light. At the time I didn’t think much of it past the initial intrigue but my discovery of my passion for space many years later had me thinking about how this might be used.

I had been reading about the hundreds of exoplanet discoveries for a while when I heard of 2M1207b which is thought to be the first directly imaged planet outside our solar system. It’s an exceptional planet being an extremely hot gas giant orbiting a very dim companion star. For systems like our own there would be no chance of seeing any planets from the outside thanks to our extremely bright sun and our relative proximity to it. Still knowing that light had the novel ability to cancel itself out I had wondered if we could say build an apparatus that forced light from a parent star to cancel itself out, letting us peer behind the blazing might to see what lie beneath.

It wasn’t until a few years later when I stumbled across the idea of a StarShade which had been proposed many years previously. In essence it would function as an augmentation to any space based telescope positioning itself perfectly in front of the parent star and reducing its brightness by a whopping 10 billion times. In comparison then the tiny planets which were once outshone would glow bright enough for the telescopes to be able to see them directly, hopefully leading to direct detection of many planets orbiting the star. Unfortunately it appears that this project is now defunct but that doesn’t mean the idea doesn’t live on in other forms.

Most recently an international collaboration of scientists developed a Apodizing Phase Plate coronagraph which is in essence a scaled down version of a starshade that can be installed in current telescopes:

Installed on the European Southern Observatory’s Very Large Telescope, or VLT, atop Paranal Mountain in Chile, the new technology enabled an international team of astronomers to confirm the existence and orbital movement of Beta Pictoris b, a planet about seven to 10 times the mass of Jupiter, around its parent star, Beta Pictoris, 63 light years away.

At the core of the system is a small piece of glass with a highly complex pattern inscribed into its surface. Called an Apodizing Phase Plate, or APP, the device blocks out the starlight in a very defined way, allowing planets to show up in the image whose signals were previously drowned out by the star’s glare.

It’s not just planets that this device helps discover either, it can also help detect distant objects that are hidden behind brighter ones. This enables telescopes to become even more powerful than they once were with minimal modifications. Probably the best part about this is that they’re already using them on the Very Large Telescope in Chile, proving that technology is much more than just a theory.

There’s so much to discover in our universe and it always gets me excited to see these pieces of technology that allow us to pull back the veil and peer ever further into the deepest parts of space. It’s so humbling to know that you’re just a tiny piece of a seemingly infinite universe yet it’s so enthralling that I lose myself for hours just staring up at the night sky. I feel so privileged to be living in a time were our knowledge of this universe is increasing at an ever accelerating rate yet we’re still left wondering at the awesome beauty that’s put before us.

Space: Vast, Complex and Invisible.

For hundreds of years we humans have been staring off into the vastness of space for varying reasons. Initially man looked at the stars for mythical and spiritual purposes, hoping to derive meaning from what they saw up in the sky that they could then apply to their lives. As time went on we began to discover that the sky could be used as an extraordinarily accurate navigation tool that was used for hundreds of years. Even today celestial navigation is still used by modern technology to guide craft that venture beyond Earth’s atmosphere, a tribute to how useful gazing towards the heavens is.

Perhaps the most interesting part about our constant star gazing is that the more we discover the more we find out we don’t know. The following pie chart shows just how what we can see from Earth makes up a small part of the universe:

DarkMatterPie

In essence the visible universe accounts for a mere 4% of what exists with the remaining 96% being made up primarily of dark matter and dark energy. This idea that the visible universe is so small, even when you consider something like VY Canis Majoris, is something that still amazes me even today.

Consider dark matter, something that we’ve never directly observed. If you take a look around the universe you would begin to notice some strange behaviour that you couldn’t explain if the universe was exactly as we see it. Some of the best examples are effects like gravitational lensing where light coming to us appears to be bent around another object. In the case of a dark matter object we can’t actually see the object doing the bending. Whilst this would traditionally lead to a review of classical physics models (and indeed it has) observational evidence like the bullet cluster are giving strength to the dark matter model of the universe.

Even more curious is the concept of dark energy. As far as we can tell the universe is expanding at an accelerating rate. For this to occur there has to be some form of energy fueling the process and so far it is best explained using dark energy. By its definition dark energy exerts an outward pressure on the universe which is arguably weak, but it is constant throughout the universe. Current models show that previously gravity was overcoming the outward pressure that dark energy was applying to the universe. However as the force that gravity can exert does not increase as the volume of space increases eventually the force of dark energy took over, and caused the acceleration of expansion.

And herein lies the fun of science. We’re constantly finding out how our view of the universe is incomplete and needs to be updated and changed. We’re only really just finding solid data for dark matter (the bullet cluster analysis is barely 3 years old) and dark energy was coined just over a decade ago. One of my most favourite sayings from all my science teachings was :

The most interesting discoveries aren’t usually eureka moments, they’re more along the lines of “That’s not supposed to happen…”

So after millena of gazing up at the stars the biggest mystery about them turns out to be something that we can’t see. Isn’t that just so awesome? It’s like the universe watching us and waiting until we think we have everything figured out and then throwing us a giant curveball.

Maybe I just like it when secrets play hard to get 😉

The Universe, Yours to Discover.

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This year is the Internation Year of Astronomy to celebrate 400 years of astromincal observation and study. This is a great oppotunity for anyone who has even a mild interest in the stars and our place in the universe to get involved in some astronomy. I know that I will be spending the better part of this year staring up at the sky and hopefully, sharing it with everyone who is willing 🙂

I think what puts most people off astronomy is the idea that you have to get up at 1am and drive out to remote locations to get a good view of the stars. Whilst that’s true if you want the best view it doesn’t mean you can’t do some pretty good observing from the comfort of your backyard. In fact there are some great things to see and you don’t even need a telescope, although I’d reccomend picking up a pair of binoculars if you’d like to get a better look at some things.

So, what are some interesting sights to see? Personally I’d reccomend starting off with the Moon, since it’s big, bright and with a pair of binoculars you can seem some incredible detail. The other favourites are Mars, Jupiter and Venus, since they’re all fairly bright and can be seen with the naked eye.

One of my all time favourites will be the International Space Station, which you can plot sighting times using NASA’s Skywatch program. Just select your city and it will give you times that you can view the station.

If you’re hungry for more, the best website I’ve found for sightings of many different astronomical objects is Heaven’s Above. They’ve even got a great guide for deciphering all the terms that use so even if you’ve never done this kind of thing before, you’ll be able to find what you want in the sky.

I spent a weekend down at the coast when the moon was full just a couple weeks ago. I got some fantastic pictures whilst I was lazing on the beach long into the night. I’ll be sure to share them all with you here.