Going for it...

I want to talk about light pollution.
But I have a lot to say, so I am going to break it into two separate blogs.


I first heard about light pollution before I had any interest in astronomy.  I'm embarrassed to admit it, but to me light pollution sounded trivial compared to all the politically charged social issues that I believed to be most important.  I was pretty singularly interested in those subjects involving civil liberties and human rights.  To hear someone tell me we had a problem with light pollution was like a slap in the face to the things I felt to be the most righteous.  It probably didn't help that the only night I ever knew was that of suburban sprawl in which only a handful of stars exist.  I mean, what you can't see isn't there, right?  Clearly, that's the wrong attitude and in retrospect it's obvious that the opinions I held so dear in my late teens are indicative of a greater problem that (I believe) prevails in the developed world:  ambivalence to the natural world around us; something that existed before us, will undoubtedly outlive us, and ironically, the very thing that sustains us.  If more people fought for the things most fundamental to our existence, then perhaps we'd have less time to fight over the things that are, actually,  the most trivial.

The political issues of today are predominately those that are relatable for the masses: money and the religious affiliation (or spiritual philosophy) on which each of us builds our own personal identity.  So, the key is to make people care about human impact on the earth and, conversely, the impact the entire universe has on us.

And now I am getting to my point:

Science is absolutely the building blocks on which civilization is founded.  As such, the pursuit of truth through experimentation should be society's primary priority.  Not only should we learn about our natural world, but to be able to apply our discoveries so to live in accord with natural law.  As scientists, or just people who love the sciences, we have a duty to share our knowledge (and hopefully why it makes us feel impassioned) with our peers.  If we can share what we know in such a way that others can connect with it, we've done our job.  This has been the goal of this blog.  If you, the reader, have begun to view the universe with a sense of awe and amazement, then I am content.  The purpose of outreach is to cultivate a sense of universal appreciation of the world around us.

The problem is that we're losing sight of this element that is so crucial to our existence.  We've watched as our science budgets have been slashed.  Undoubtedly, we've all noticed the Republican assault on science and education.  Now, more than ever, it is of the utmost importance that we effectively demonstrate the beauty that is the natural world.  This requires a sense of humility, clarity, and most importantly, the love and fascination we each experience.  If we make science palatable to the masses we may be able to secure the national support it both requires and deserves.

So share your passion, keep learning, and communicate what you know.  And come back soon so I might unveil the many aspects of an issue so seemingly inconsequential: light pollution.

Kind of Nifty

From the cover of Scientific American March 14, 1874.

(Darn.  I'm a day late.)

Cute, but I don't think the design would have worked.

You can either zoom in or click to download the image.  I did, however, include a virus.  (I'm just kidding.  I shouldn't joke about that...should I?)

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Little Bang, Big Boom!

During the first half of the twentieth century, two theories of our cosmic origin were gaining popularity among scientists.  The first theory, originally proposed by Fred Hoyle, was that of a steady state universe: one that had always existed and would forever exist, unchanged.  The other theory was first proposed by Georges Lemaître who called his idea the "hypothesis of the primeval atom."  Using results of Einstein's newly developed theory of relativity,  Lemaître suggested that the universe was born as the result of a singular, highly explosive moment when time began.  Ironically, the latter theory was named by Hoyle, who jokingly made reference to the "big bang" during a radio interview in the 1940's.  The name stuck, and we now know the Big Bang theory to be the prevailing cosmological model today.  Sorry if I spoiled it for you, but today's refined model of the theory is no longer in contention (by the scientific community, at least).  Let me show you why.


Understandably, the origin of the universe became a popular scientific endeavor.  It was three gifted theoreticians, George Gamow, Ralph Alpher, and Robert Herman, who discovered a critical consequence of the big bang model of cosmology: that if such an explosion had taken place, there should a faint afterglow of thermal radiation still detectable today due to a temperature they pegged at about 9 or 10 Kelvin.  


The next big thing happened in the 1960's when two Bell Labs physicists, Arno Penzias and Robert Wilson, attempted to map hydrogen emissions within our own solar system.  Since emissions would be faint, it was necessary that any background noise be eliminated from their equipment.  After painstakingly trying to remove a constant background hiss, the gentlemen concluded it was simply a condition of the sky itself, since it appeared equally in all directions.  It was only after discourse with other physicists that the pair realized they had found the elusive relic radiation called the Cosmic Microwave Background Radiation (CMBR).  So, not only did they mistakenly discover the the key to an explosive moment at the beginning of time, the pair also accidentally won the Nobel Prize in 1978. #Prettysweetdealforthosetwo.


The Cosmic Microwave Background was, perhaps, the discovery that catapulted modern cosmology into a precision science.  Now having collected data from more than a few missions (COBE, WMAP, and, most recently, Planck, to name a few) cosmologists have been able to begin building an understanding our cosmic origins.




Let's paint a picture of the infant universe:

In early theories of the big bang, it was believed that the distribution of matter and energy should be chunky.  This makes sense, right?  Explosions we see on earth are chaotic and result in a non-uniform distribution of mass.  The problem is, pictures of the CMB show us a relatively isotropic universe. 


See?

Image from WMAP

Okay, so there are a few cold spots, but the universe is just too uniform to be explained by a single burst.  The solution: inflation.  We now believe that the universe was born in a smaller bang and then experienced an intense period of expansion we call inflation.  I think it's important to mention that the physics under which our universe exists today may not have dictated the instant of our birth.  I say instant because everything, the bang and the beginning of inflation until its end, quite literally happened in a blink of an eye.  Here's a timeline:

I found this here. 

In my human perception of time, I estimate that inflation lasted about one fiftieth of an instant, and it was likely the most intense sub instant our universe has ever seen.  This is why I propose we rename the big bang theory Little Bang, Big Boom!.  Who's in?!


Getting back to it: this altered theory describes the pretty picture imaged by WMAP.  It was the initial (little) bang that spread out matter and energy ever so slightly, while the second (big) boom effectively distributed the material into the relatively homogeneous universe we see today.  Ta da!


Anyway, the above visual doesn't show it, but it was really hot back then.  It also fails to show you the ingredients of quark soup.  Let me tell you:  

• Separation of the weak nuclear and electromagnetic forces.
• Antimatter/matter annihilation -- leaving more matter .  Obviously (look around you). 

That completes my understanding of the first second ever.

Now here's the part we care about in the current second:

As the universe continued to expand, it cooled to a temperature (3000 K) that would finally allow nucleosynthesis to happen.  This means that all those excess electrons which had roamed free for a second would combine with those free protons to form hydrogen.  We call this recombination.  Although the name would imply otherwise, this was actually the first time this process had ever happened (in this universe...).   These indivisibles (atoms were named by Democritus, you know) are important because suddenly photons could travel through swarms of them without getting stuck or absorbed.  The fog had lifted.  Literally.  The universe was opaque until recombination took place.  Consequently, CMBR is the earliest light we can detect.  


Don't feel left out; you can see it too!  In fact you probably already have.  You know when your television loses signal and the screen becomes all fuzzy?  Well, some small percentage of that snow is actually the CMB.  

I mentioned a few missions that have played key roles in our understanding of this remnant light.  The first was the COsmic Background Explorer (COBE).  The driving force behind this project was John Mather.  He, along with another key player, George Smoot, actually won the 2006 Nobel Prize in Physics for their roles in examining the cosmic microwave background.  The mission launched in 1989 and after only nine minutes of observation, COBE had registered a perfect blackbody spectrum corresponding to a temperature 2.7 degrees above absolute zero.  This explains why we detect the CMBR in the microwave region of the spectrum: the lower the temperature, the longer the peak wavelength of the spectrum.  

COBE meant a lot for cosmology because one experimental aspect (led by Smoot) sought to map the slight fluctuations in the temperature of the background.  Smoot's hypothesis was that should these anisotropies exist, studying them could help us understand the formation of stars and galaxies by illustrating where matter began to aggregate. If matter were to accumulate, it would only be a matter of time before gravity would take over to form the systems we study today.  We think these ripples are cosmological keys, and, since COBE was actually only precise enough to measure the larger fluctuations, we have continued to study these anisotropies with better technology and greater depth.  


In the late nineties an instrument called BOOMERANG flew around Antarctica on the back of a stratospheric balloon.  Its mission was to map a much smaller portion of the sky with great precision.  Another fun balloon mission was MAXIMA which, like BOOMERANG, explored a much smaller angular range than COBE.  


Next came the Wilkinson Microwave Anisotropy Probe.  Believe it or not, you know WMAP.  This is the mission from which we get the age of our universe: 13.7 billion years.  WMAP is also responsible for telling us the geometry of space: it's Euclidean.  That is to say, as far as we can see space is flat.  Clearly the Wilkinson Microwave Anisotropy Probe was a fantastically successful instrument, and I think Science magazine sums it up nicely,  "lingering doubts about the existence of dark energy and the composition of the universe dissolved when the WMAP satellite took the most detailed picture ever of the cosmic microwave background (CMB)." - Science Magazine 2003, "Breakthrough of the Year" article.  

The most recent exploration of the CMB is the Planck mission, a European Space Agency project (with many partners, like NASA) that launched in March 2009.  This probe, now retired, sits at the second la grange point about 930,000 miles away (so, like us, it orbits the sun).  You can read a little about Planck's discoveries here, although they've only just begun sifting through all the data the instrument delivered.  


Our little world and the universe are so intertwined in ways we don't even know (or sometimes acknowledge).  I think its incredible that humans, who've only been around for a few thousand years, can actually study 13.7 billion years into the past and appreciate its importance.   

Here we go...

Let's talk about the speed of light.

I'm serious.  I know this may seem remedial and basic, but our perception of the universe is entirely dependent on this seemingly simple concept.

(The following paragraph is paraphrased from our book, so if you read chapter 3, feel free to skip ahead)

It was in 1675 that the speed of light was first measured with some accuracy.  The scientist was Ole Roemer who, in an attempt to predict future eclipses of Jupiter's moons, determined that it took 22 minutes for light to travel across the diameter of the earth's orbit.  Roemer's approximation was a bit generous as we now know that it takes light 16.5 minutes to travel 2 AU.  Just to remind you, the distance between the earth and the sun is defined as 1 astronomical unit (AU).  The speed of light in a vacuum (c), as measured in 1983, is exactly 299,792,458 m/s.  We can say this value is exact because this constant is actually the number on which the meter is defined.  In terms of miles: light travels 186,282 miles/second.

We've all heard it: light speed is the cosmic speed limit.  Nothing can travel faster.  I think it's tough to put this idea into perspective because in day to day experience light seems to travel instantaneously.  There's no lag time when we turn on a light or when we talk on the phone.  Consequently, we regard the speed of light as infinite.  But in an astronomical sense, the speed of light is really kind of slow.  Let me show you.  It takes light 1.3 seconds to travel from earth to the moon, our closest celestial object.  Another rover, Curiosity, is scheduled to land on Mars less than seven months from now.  When it does arrive, communication to or from the machine will take 4 minutes.  Now at the edge of our solar system, it takes over 29 hours to receive data from Voyager 1.  The closest star (that we know about), Proxima Centauri is 25 trillion miles away and its light arrives here on earth in 4.2 years.  If these are our closest neighbors, you can understand why astronomers would want to define a more efficient unit of distance.  So the light year was born and it is defined as the distance that light travels in a year.  Got it?  It is not a measure of time.  Don't be fooled.

1 ly = 9,460,730,472,580.8 km ≈ 5,878,625,373,183.6 mi ≈ 63,241.1 AU ≈ 0.306601 pc

Clearly there is no shortage of ways to express large scale distances.  But no matter how I say 9,460,730,472,580.8 km, understanding a magnitude that large is simply beyond my grasp.

The entire field of astronomy is based on the fact that when we look at distance objects we are looking into the past.  Because light is not instantaneous, we can catch a glimpse of the beginning of the universe, we can watch galaxies form, and ultimately, begin to understand how we came to be.  The constant speed of light is the thing that allows us to examine our very existence.

This constant is just so cool.  I almost feel like I don't have the words to really do it justice.  But I'm going to try to make you care anyway.

So, light is an aspect of nature that dictates how we view the universe.  What are its ramifications?  Take a look:

• Red Shift 
• This important concept was studied by Edwin Hubble during the first half of the 20th century.  As he looked out at the universe (this happened to be on the 100" Hooker telescope) he noticed that many objects were shifted toward longer wavelengths thus appearing more red.  He determined that this redshift, as it was called, was due to the expansion of space itself and that galaxies are flying away from one another at an ever increasing rate.  Objects receding slowly, he discovered, had a small redshift and those with a larger redshift are not only more distant, but they are flying away at even higher rates.  Hubble suggested a rate of expansion now known as Hubble's constant.  By using (wait for it) the 200" Hale telescope, Allan Sandage was able to measure redshifts with considerable accuracy thus confirming his mentor's prediction.  We now know the universe to be some 13.7 billion years old.

• Light Horizon
• We have this gift of a constant speed of light.  There's a catch though; this same gift is also our ultimate limitation.  If the universe is 13.7 billions years old, that would imply that it would take that amount of time for the earliest light to reach us.  Right?  Well, due to the expansion of space, it is estimated the we can detect signals of light from anywhere within a radius of about 46 billions light years.  This is often referred to as our light horizon or the observable universe.  It is the sphere around us that is the absolute limit on how far we can see.  Does space end there?  Probably not, so any observer anywhere in the universe has his own light horizon.  

• Cosmic Microwave Background
• The most distant thing we can currently detect is remnant light from shortly after the big bang itself.  Called cosmic microwave background radiation, this light played a crucial role in determining a theory of an expanding universe.  Several missions have studied and cataloged this ancient radiation with interesting results.  This will be the topic of my next blog, so stay tuned.

• Biology 
• The value 'c' refers to speed of light in a vacuum, the vacuum part being key.  186,282 miles per second is actually too fast for our eyes to respond to light.  Conveniently enough, we know that light slows as it travels through things like glass or water.  This is because as it travels through these materials it gets absorbed and then re-radiates, causing a delay that slows the light to about 124,000 miles per second (still fast).  This is why a lens works; it can bend and concentrate large quantities of light.  It's incredible to think that our eyes have evolved to perfectly accommodate this quality of light.

• Interstellar Travel 
• Few ideas excite us like that of traveling through space-time.  Highly imaginative entertainment outlets have glamorized the adventure that would be extragalactic travel.  I think a lot of us hang on to the hope that perhaps one day the impossible will become a reality.  Even if it remains an impossibility forever, space travel is a fascinating thought experiment.  How would we do it?  Even light is too slow to travel any distance in a human time scale.  We've all heard of Einstein's famous equation, E = mc², right?  It basically says that as speed increases towards that of light, mass also increases to infinity.  Meaning, it would take an infinite amount of energy for an object with mass (like a spaceship) to travel anywhere near the speed of light.  And we know that to be impossible. But,what if we could exploit the very nature of space-time to aid us in our quest?  In other words, maybe we can cheat the cosmic speed limit.  Wormholes seem to be a favorite of scientists and non scientists alike.  By punching a hole into the very fabric of space-time, it's been suggested that we can travel to another place and/or time in the universe.  Of course manipulating a wormhole to a.) appear and b.) do as you like presents a whole other slew of problems.  I don't think we'll find ourselves traveling to some fantastic exoplanet via wormhole any time soon.  My favorite concept of interstellar travel involves a special kind of spaceship that would fold space to propel it to speeds beyond that of light.  Of course, all these concepts are speculation.  I wouldn't be surprised if there are scientists who have seen the end of their careers because of overzealous deliberation of these matters.  This doesn't mean this topic is void of real scientists.  You can check it out yourself here.

Anyways...

What about neutrinos?  You think those suckers were traveling faster than light?



Next time: The cosmic microwave background.  Stick around.

Who knew science could be so juicy?

I hadn't intended on posting more about Palomar Observatory. Really.  But it deserves one more shout out.  Today marks the anniversary of the day the 200" Hale telescope saw its first light.  I sort of mentioned it in my last post, but Palomar Observatory is historically significant because it is the thing that allowed astronomy to flourish in Southern California.

Thanks to the fantastic fundraising abilities of George Ellery Hale (a solar astronomer), the Mount Wilson Observatory was founded in 1904 with a grant from the Carnegie Institution of Washington.  There is a lot of information about Mt. Wilson and its 100" Hooker telescope.  I suggest you read about it.  Here's a link.  Unlike today's observatories, Mt. Wilson employed a whole host of its own astronomers, like Edwin Hubble, who made incredible contributions to astronomy.  This place was important, even Albert Einstein took a trek up that mountain to get a look at the serious science.  But here's why Palomar is so much cooler.

You may be aware of a longstanding rivalry between the Rockefellers and the Carnegies?  Well, if you were unaware, it's a real thing.  When Hale began to raise money for his pet project, the 200" telescope, he found the only group willing to fund his telescope was the International Education Board, who, oddly enough, was an organization of the Rockefeller foundation.  Not surprisingly, the International Board of Education was unwilling to award this new observatory to a Carnegie facility.  So Hale was promised $6 million to build the observatory and the telescope with one stipulation: the recipient would be the newly established California Institute of Technology and before they could have the money, they would need to secure an endowment to finance the observatory's operation costs.  Luckily, a wealthy banker agreed to do just that.

Without even trying, Caltech had accumulated its own observatory.  They didn't have astronomers, nor did they have a department or an optics lab.  But hey, at least they would have the world's largest telescope, right?  So began the tumultuous (and weird) marriage of Caltech and Mt. Wilson.  Mt. Wilson gave Caltech astronomers, Caltech shared its telescope and used that lovely endowment money to build a department and the optics lab that would be used to finish Palomar's 5.2 meter Pyrex mirror.

The end.

Okay, it's not the end.  But it's a whole lot of personalities and this blog is supposed to be about science.  Suffice it to say that that marriage has since dissolved, Caltech runs its own astronomy department and several telescopes, Mt. Wilson is still a cool place to visit, and the Carnegie Institution of Science is still around and thriving.

So back to it.
First light at Palomar occurred 63 years ago on January 26, 1949 when Edwin Powell Hubble pointed the 200" Hale telescope at NGC 2261.  Sadly, Hale did not live to see his dream realized.  His memory, though, lives through this telescope.  Like Hale always said, "make no small plans, dream no small dreams."

Technology continues to improve, but the infrastructure surrounding this mirror (and the mirror itself) is all original.  The spare gears built sixty some years ago are still hanging on the wall having never been used.  In fact, the observatory is so confident these spare gears won't be required that they built a brand new adaptive optics lab right in front of them.  That lab is now home to the world's premier adaptive optics system, the Palm 3000.
This truly is the perfect machine.

To 63 years, Palomar, and many more to come.


Not many institutions can claim sole ownership of such a spectacular facility. It is worth noting, however, that the Carnegie Institution is a partner on the Giant Magellan, a 24.5 meter telescope planned to be functional in 2018.  They've completed one of seven 8.4 m segments and finished casting the second.  Caltech and the University of California (hey, that's us!) have plans for a 30 meter telescope (along with partners Canada and Japan).  But alas, the Europeans are in the lead with their planned Extremely Large Telescope that would be 39.3 meters.  Wow.

My next post will be about science.
I promise.

You want to do what?!

People often ask me what I'm studying in school.  If I respond with physics or astronomy, the question that inevitably follows is, "What are you going to do with that?!"  Generally, the tone of complete and utter confusion tells me that people don't fully grasp the importance of physics, nor do they realize that people actually work as astronomers.  So, let's talk about what an astronomer is.


This is an astronomer:

Above is Fritz Zwicky.  He, along with Walter Baade, originated the term "supernova".  In the days of photographic plates, Zwicky found more than 100 supernovae.  Most notably (to me, at least), Zwicky was known for coining the term "spherical bastard", because no matter the angle you look at one, he's still a bastard.

Astronomy began to make great strides during the start of the 20th century.  With the construction of Mount Wilson Observatory in Pasadena, Palomar Observatory some 100 miles south, and the consequent birth of Caltech's astronomy department, many of the world's premier scientists were concentrated in southern California. As a result, several books have been written depicting the fascinating lives and careers of this generation's astronomers.  Two of my favorites include The Perfect Machine and Lonely Hearts of the Cosmos.  The former tells the tale of the construction of what was the world's largest telescope for nearly 50 years.  The latter chronicles the life of Allan Sandage, a careful observer and a graduate student of Edwin Hubble.  I admit that stories of the many characters of these institutions has certainly romanticized my view of astronomy.  While a few things have changed (women can now observe, and many telescopes are used remotely), these important facilities and people set the tone for observational astronomy that prevails today.


Running a telescope used to look kind of like this:

Here Edwin Hubble sits at prime focus of the 200" Hale telescope.  Before computers, each telescope required that someone follow a guide star as the telescope photographs other celestial objects.  Guiding was generally a job for a poor graduate student as prime focus can be extremely cold and uncomfortable.  

Modern day observing is quite pleasant.  Astronomers sit in a data room with heat, automated guiding (generally) and, most importantly, coffee.  The data room doesn't even have to be at the telescope.  The twin Kecks, for instance, can transmit data to computers at almost any partnering institution.  Which means real time data can be sent into a room right here on campus in Pierce Hall.

Not all telescopes require direct use of an astronomer.

Today, with remotely controlled telescopes, and automatic programming, a lot can be discovered with little assistance from an astronomer.  Take, for instance, the Palomar Transient Factory.  This fully automated, wide field sky survey utilizes several Caltech operated telescopes.  The main machine is the 48" Samuel Oschin telescope atop Palomar Mountain.  Weather permitting (which is about 300 nights a year) the telescope scans the sky in search of transient objects.  The whole northern sky is photographed every few days.   Data is sent to Berkeley where it is analyzed by an automated computer.  Should the program find an anomaly, it sends a command back down to Palomar where the 60" telescope will point to that swath of sky.  Once again the data is sent back up to Berkeley.  Should the peculiarity persist, a person gets woken up, and another astronomer (either on one of the Kecks or the Palomar 200" Hale telescope) gets their night interrupted while that telescope images that anomalous portion of the sky.  (It is my understanding that an astronomer is much more likely to get telescope time if he agrees to be interrupted by the PTF should it be necessary.)  In April 2010 a new supernova was discovered in just 29 minutes by this system.  It took Fritz Zwicky his entire career to discover his 120 (I think) supernovae.

Even with technological advancements, astronomy has always been (and will continue to be) an extraordinarily creative pursuit.  It's just the nature of science.  Astronomers seek to answer the questions that excite us all while simultaneously making us each a little woozy (please tell me I'm not the only one who gets light headed while pondering the mysteries of the cosmos).  Astronomers are the storytellers of the vast expanse that is our universe.  But their stories require data; lots and lots of data.  Not only is collecting good, usable data an important role of an astronomer, but an equally crucial ability is to effectively interpret that data.  For that reason, astronomers are observers, theoreticians, mathematicians, computer engineers, technicians, programmers, and dreamers.
They are also persistent.
And patient.
Because they wait for telescope time, and they wait for some poor student to slowly learn how to reduce their data.  And they're nice.  Astronomers are nice.
They pay close attention to detail.

In a nutshell:
In a quest for answers to the most fundamental questions of our existence, savvy astronomers collaborate with one another to stitch together a true picture of the cosmos.

Next time someone asks me what I would do with an astronomy degree, I'll tell them to visit this link.

Celestial Cheese

Choosing a name for this blog seemed to be an unnecessarily difficult task for me.  Given that the topic (astronomy, if that wasn't made clear by the title) is exactly what I'm trying to learn, picking a name that didn't make me look like a complete fool seemed tricky.  When racking my brain got me nowhere, I began to reference books and the interweb.

Hoping to find a good alliterative phrase, I first scanned a list of astronomy terms.  No luck.
Meanwhile, the phrase 'night vision' kept popping into my head.
No.  Absolutely not.

Next, I decided to marry astronomy with my one true love: cheese.  Naturally, I typed "astronomy cheese" into google.  This was almost as disappointing as my search for astronomical alliteration.  I did, however, discover that there is a wine, cheese, and astronomy festival in New Zealand every year.  I also found several terrible cartoons referencing our moon's very cheesy composition.  Oh, and I discovered a triple creme called Moon Dust Cheese.

See?

Note:  This is a Trader Joe's display.  I work for Trader Joe's and I assure you I never saw this cheese.  But, seriously, a triple creme cow's milk rolled in ash?  I would have eaten all of it.  Apparently, this cheese was available on the east coast stores during October.  Bummer.

Most importantly, in this pursuit of cheese and stars, I discovered proof of something I've always believed.  Astronomers have great senses of humor.  Check out this 2006 April Fool's Joke from the people at Astronomy Picture of the Day.

Anyways, back to the naming this blog:

I apparently settled on the name "First Light".  It's not terribly witty, but I think the concept of the first light collected by a telescope is a good parallel to the journey that begins here, with my first astronomy course.