Communicating Science to the Public

   The government is really struggling with funding for science.  We’ve been hearing about this for years now, it’s no big surprise anymore. With every new budget comes a funding cut to science. But why is this the case? Why does the government feel that science is not important, and doesn’t deserve funding? As a scientist who depends on government funding to pay my salary and further my research, I sure think it’s important, but how can we convince the government and the people of this? Communication is the key. Scientists need to become better communicators, we need to share what we do with the world in a way that they can understand and appreciate it. It is only then that science will grow more important in the minds of the government and the general public.

   Take the Mars rover Curiosity as an example. I’d be willing to bet that 90% of the general public had no idea this robot was being built until a month or so before it landed, not launched, but landed on Mars. People included in that 10% are the scientists and engineers of the world, people who read astronomy magazine or other scientific magazine, and those that live near cape Canaveral and watched the news a few days before the robot was launched. The other 90%, well, they caught wind of it sometime in June/July 2012 when publicity about how difficult the rover landing was going to be came about. It was then that the news stations began picking up the story and it was broadcasted all over the country and the world. Someone finally flipped that switch and communicated with public that this was pretty darn cool, hard and amazing. And it worked! People began to care about science. Everywhere I went to give outreach talks people asked me about the rover. They may not have known its name, or what its true purpose was going to be on Mars, but they wanted to know more. They cared. And that got me excited because I could then share more about how important this robot and our discoveries on Mars are. I just wish that everyone had heard about it sooner!

   Maybe it was the 7 minutes of terror NASA video, or maybe it was the curiosity Facebook page that got people interested. But at the heart of it all, it was a few scientists who figured out how to communicate. They figured out how to get the public as excited as they are about the project. Evidence of there success can be seen in these photos: http://www.behance.net/gallery/Mars-Curiosity-Rover-Landing/4750667. Photojournalist Navid Baraty snapped images of people at Times Square in New York City watching the landing at 1am in the morning. Over 1,000 people gathered in NYC and watched as Curiosity survived the 7 minutes of terror and successfully landed on Mars. They were convinced that this was awesome!

   This is what we as scientists need to strive harder to do: teach people that what we do is awesome and worthwhile. And we need to start much sooner. We have to convince people in the beginning that the money we will spend to build robots and telescopes will produce interesting and worthwhile science. We need funding now for future projects. We can’t wait until the next robot is on its way to Mars, or whatever planet it’s headed for. We need to convince people today to help fund future missions while they are still in the design stage. Convince the government to keep science going by providing the appropriate and necessary funds.

   I’ll finish this post with a prime example. Recently, a group of planetary scientists (including the beloved Bill Nye the Science Guy) went to congress to protest further cuts in the fields of astronomy and planetary science. Currently, they are planning another mission to Mars, and more importantly (in my opinion) a mission to Europa. Now if you don’t know anything about Europa, here’s the interesting stuff: Europa is a moon of the planet Jupiter that likely has a sub-surface liquid water ocean. Yes, another solar system body with oceans similar to those on Earth. Scientists want to send a robot to Europa to drill through the ice surface to see if there actually is a water ocean there, and if there are any signs of life in that ocean. For all we know, there could be bacteria, fish, or even mermaids (ok maybe that’s a stretch, but still) living on another solar system body! Now I don’t know about you, but I think that’s pretty darn cool! Equally as awesome as the Mar’s rover, if not more exciting! But sadly, this mission on the chopping block. If we can’t convince the government, and people in general, that this is a worthwhile effort, the 2014 budget cuts will wipe it off the table. We will never know if there is life on Europa, unless we start telling everyone about this awesome endeavor.

   We need to communicate and spread the word about how awesome everything that all scientists, not just astronomers, are doing. Then maybe we won’t have to worry so much about budget cuts and the future of science will become much more bright.

Time Asymmetry

I read a short article in Discover magazine today, which can be found here, about a new discovery that some physicists made. What exactly happened was not very clear to me, and I think it would be confusing to the public as well. So I thought I’d try to re-explain what I believe is going on, using some relatable examples below. Hopefully I have the right idea now, and you can appreciate this discovery a bit more!

To quote the article title: Physicists discovered, as theoretically predicted, that time flows asymmetrically at the electron (very tiny particle) level. But what does this mean? Well first, let’s review how we perceive time. Time, to human beings, is a forward moving unchangeable entity. Time passes for us everyday, and we can’t ever go backwards in time. If we were to run time backwards, we should see ourselves re-experiencing everything that happened that day, just in reverse. For example, if I video taped you driving to work and walking into your office, then played the tape backwards, I should see you walking backwards out of your office and driving home from work in reverse. Therefore, for humans, time is symmetrical. What happens forward in time must happen exactly the same way, but backwards, if time were played in reverse. So what is this time asymmetry these physicists are talking about? Scientists at the CERN particle accelerator have been smashing tiny particles together at very high speeds, and watching what happens to them when they collide. They know that when you smash two particles together, you should see the pieces that the particles are made of as a result. Think of it like a car crash. You’re driving down the road and you see two cars collide in a head on collision. When these cars collide, the pieces of each car are strewn about the road. So when you collide two things, you’re left with the bits and pieces of the inner working of that object. So what does this have to do with time not being symmetric? Ok, let’s run this car crash scenario again. You see a SUV and a mini van crash on into each other. Time is flowing forward when the cars crash, and lets assume both cars crash and all their constituent pieces are on the road. Now, we can theoretically make time flow in reverse, by collecting all the pieces of the cars and rebuilding them.  Putting the cars back together is similar to flowing time in reverse, essentially arriving back at the pre-crash state with two unharmed and functional vehicles. Now, you would expect that if I have all the pieces and put both cars back together, I should end up with an SUV and a mini-van again. This would be an example of time symmetry. But what if I put all the pieces of the cars back together, and ended up with a small car and a truck, instead of a SUV and a minivan? Al cars are made of (essentially) the same parts, so in theory I could end up with two different cars than I started with. I’m essentially running time in reverse, but I’m not arriving back at exactly the same pre-accident state. The end result is two completely fixed vehicles, but not the SUV and mini-van I started with. This is time asymmetry. Running time in reverse does not get me back to my starting point. Physicists realized that if they watch a specific particle, which likes to “change state” (you can think of this like a coin, which can be heads up or tails up, depending on how the coin is sitting), when it changes state (flips from head to tails) it does not always change back to its previous state, if time is run in reverse (the coin is flipped again).

They also realized that time has a preferential direction. Let’s go back to our car crash scenario. The SUV and the mini-van crash. When time is run forward, the crash occurs and the pieces for the mini-van and SUV are on the road. When run in reverse (the cars are put back together), sometimes you end up with a mini-van and SUV, sometime you end up with two completely different cars. The fact that when time is run forwards, you almost always see the SUV and mini-van collide, means that the laws of physics, as we understand them, prefer time moving forward. Things don’t always “make sense” when time runs backwards. So in this example, time preferentially moves forward. It was unclear to me in the articles I read whether the scientists findings showed forward or reverse time as preferential, but it’s fascinating that they are not the same! Intuitively time running forward or backward should yield the same result, but it does not! Now remember, this only happen in the sub-atomic world. This doesn’t actually happen on car-size scales. But still, this result changes how we perceive time at the smallest level, and ultimately our understanding of the universe as a whole! 

Orion Proplyds

The Orion Proplyds were first discovered by the Hubble Space Telescope. Astronomers expected the Orion nebula to be a host for lots of star formation, and were amazed to see that Hubble could resolve individual young stars. The Proplyds are young stars surrounded by a gaseous circumstellar disk . In the image of the Orion Nebula above, the proplyds are enlarged so you can see the bright central star surrounded by a dark oval shaped ring. The disks appear dark because they are absorbing the light emitted by the nebula, and re-emitting it in the infrared, a wavelength of light that does not appear bright in these images. Portions of these disks will eventually fall onto the star, and the rest will either form planets, or be dispersed back into the nebula. Astronomers are using these, and other images of young stars, to learn about how stars form and how planetary systems evolve.

Image Credit:

NASA, ESA, M. Robberto (Space Telescope Science Institute/ESA), the Hubble Space Telescope Orion Treasury Project Team and L. Ricci (ESO)

American Flags Fading on the Moon

Image of an American flag from the moon's surface during the Apollo missions

During each Apollo mission that made it to the moon, the astronauts  left behind an American flag. Each was attached to a poll, and designed to wave horizontally in the low gravity environment. Astronomers have been studying these flags over the years using moon orbiting satellites to take photos of them. Even though they are not able to resolve the flag in the images, they can see a color difference in the photo where the flags sit. In more recent photos, astronomers have noticed that the flags appear a little brighter than they expected. Why is this? They think that the flags are fading, big time! If you've ever flown a flag outside and left it out all summer long, then you might have noticed that the colors look a little less bright over time. Now imagine this same flag on the moon, where there is little to no atmosphere to protect the flags from being bombarded by harmful UV radiation. It's likely that the sun has not only faded these flags but sun-bleached them white! Regardless of what they look like today, they are still a symbols of the fantastic accomplishment of landing man on the moon. 

Image Credit: NASA/Apollo Mission

Shiny Martian Rocks

The Curiosity rover has been exploring Mars since early August, and has taken many beautiful photos of the Martian landscape. In early October, Curiosity took its first scoop of Martian soil to be placed inside SAM, an instrument which analyzes the composition of Martian soil. With the scoop of soil in hand, curiosity photographed the area where the sample was taken, and stumbled upon a strange looking shiny object (center of above image).  At first, astronomers who analyzed the photograph thought the object was a small piece of shrapnel from when the rover landed.  This brought testing to a halt, because astronomers did not want to run a piece of sharp shrapnel through a very delicate machine meant to filter and analyze soil. About a week prior, Curiosity photographed a piece of plastic with ChemCam that likely broke off during it's descent, so it was very possible that this was another piece. Just to be safe, Curiosity dumped the soil. Upon closer inspection of this shiny rock, astronomers realized that this was not a piece of metal or plastic, but rather a strange rock of Martian origin. What these rocks are made of is still unclear, but Curiosity can now safely use SAM to analyze soil samples and hopefully find out the composition of these rocks!

Image credit:

 NASA/JPL-Caltech/MSSS

Iapetus, the Dinosaur Moon

Iapetus is a moon of Saturn with a funny name and a funny geological feature. I always think of it as the "dinosaur moon", because it has a distinct ridge feature on its surface that reminds me of the back of a dinosaur. Orbiting at 2.2 million miles from Saturn's surface, it's farther away from Saturn than Titan is. The surface of Iapetus was imaged by the Cassini mission in 2004, and the images revealed the equatorial ridge, a 6 mile high mountain range. It's a bit unclear how this band of mountains ended up on Iapetus. One theory is that a long time ago, Iapetus had a ring similar to Saturn's ring. As the moon evolved, the ring began to collapse onto the surface, and this ridge is where all the material collected. A second idea is that the ridge formed during a time when Iapetus was spinning on its axis much faster than it does today. Bodies in space, such as the Sun and the Earth, spin on their axis. Because of this, they bulge just a little bit in the middle. So Earth and the Sun are not perfect spheres, but rather balls that are slightly wider at the center. If Iapetus was spinning really fast some time in the past, this ridge might be the result of the moon bulging in in the middle. Astronomers will have to take a closer look at the composition and orbital properties of this moon before they can determine exactly how the ridge formed.

Image Credit: NASA/JPL/Cassini

Astro Plans for 2013

It's that time of year when everyone is making new year resolutions, and I am no different. My goal this year for you, my readers, is to write a blog post at least once a week. So today, I thought I'd share with you some exciting events of 2013; a hint at blog posts to come.

This year is going to be just as exciting as years past for astronomy enthusiasts. NASA has many missions planned, including the launch of the Interface Region Imaging Spectrograph (IRIS), Lunar Atmosphere and Dust Environment Explorer (LADEE), and the Mars Atmosphere and Volatile Evolution mission (MAVEN). These instruments are designed to study the solar atmosphere, moon's surface, and Mars' upper atmosphere, respectively. Along with these new satellites, NASA and other agencies will continue  to support the International Space Station and science experiments being conducted there.  The ESA will also be very active in 2013, focusing on launching satellites to study the Earth as part of their Living Planet Programme. Work will continue on the James Webb Space Telescope (JWST), and the construction of the Atacama Large Millimeter/submillimeter Array (ALMA) should be completed. Data continues to pour in from the Great Observatories Hubble, Chandra, and Spitzer, along with various missions exploring our solar system. Astronomers are actively studying this information and continue to make discoveries pertaining to star, planet and galaxy evolution. The Kepler space telescope, along with ground based observatories, continue to discover new exoplanets on a weekly basis. Maybe an Earth analog will be uncovered in 2013? Towards the end of 2013, be on the lookout for comet ISON. It's expected to whiz by Earth in December, and will appear as a small dot as bright as the full moon traveling across the sky.

For more information on these events, and, of course, some basic astronomy topics explained, check back on a weekly basis!

Image Credit: NASA/JPL-Caltech, space.com

Can I See the Stars?

Clear skies are essential for astronomers, but depending on where you live they may be few and far between. If you want to do some star gazing, but aren't sure if the weather will cooperate, take a look at the clear sky clock (http://cleardarksky.com/csk/). All you need to do is click "find a chart" and enter your location (or chose a state then city). What you'll see is a chart telling you all sorts of weather predictions, but the most important one is the cloud cover. Above is a clear sky chart for Kitt Peak, AZ, and you want to look at the top row of boxes to see if the sky will be clear. The color of the box at a given time tells you if there will be clouds in the sky (white), or if the sky will be clear (dark blue). So it looks like the sky will be cloudy before midnight Saturday, and then crystal clear the next day and a half. Below the chart there will be a description of how to read the chart and what the colors correspond to exactly. The chart is usually very accurate and astronomers use it all the time while observing. So the next time you want to go to a local star party, but aren’t sure if you should bother going because it might be cloudy, take a look at the clear sky chart before you head out.

Department Store Telescopes

Have you been looking up at the stars recently and thought about purchasing your own backyard telescope? Have your kids put telescope on their holiday wish list? Do you want to learn how to take photos of astronomical objects? If you answered yes to any of the above questions, then I have one piece of advice for you: don't buy a department store telescope! Yes they are inexpensive and promise to show you beautiful images of the moon and planets, but they are more hassle than they are worth. I've had many friends and family members purchase these telescopes, struggle with their kids for hours in the back yard trying to see something with it, only to package it up the next day and toss it or re-sell it. Why are these telescopes so "bad"? Well, bad is really a poor choice of words. They are usually refracting telescopes designed to look at large bright objects, and they do a good job of that. One of the main complaints I get from people is that the images look blurry, so they try to magnify the image by inserting a higher magnification eyepiece, in hopes of getting a clearer view. What they don't realize is that magnification only blurs the image more. Theses telescope are small (usually a few inches wide) and only collect so much light. Magnifying that light is not going to make things more clear or brighter, its going to enlarge a small dim region, and likely make it look darker than before. The image you see will never look like the one on the box, guaranteed. The second complaint I hear is that they are difficult to "point", as in, even if you think you have it aimed at the moon, you can't see anything. This is a problem with all small, non-computerized telescopes, and can get really frustrating really quickly. My best advice here is to be patient and try to learn your way around the sky. Point the telescope towards the moon and practice lining it up by looking at the stars with your eyes, then through the telescope, and adjusting as necessary. Practice makes perfect with this. Lastly, you must remember that we live on a moving rotating sphere, and therefore, when you point your telescope at an object, it will only stay in your field of view for a short time before you have to readjust. This is true for all telescopes, unless you have one that "tracks".

So, I very much encourage you to buy a backyard telescope, and I don't want a bad experience with a cheap scope to detour your love of astronomy! You can still acquire an excellent, easy to use telescope for a few hundred dollars. Check out websites like http://www.celestron.com/ and http://www.meade.com/ and do your research! Ask friends in a local astronomy club what they suggest, or attend a telescope buying seminar. Often, local museums will offer workshops on how to purchase and operate basic telescopes for the beginner. Check these out, avoid the department store telescopes, and I promise you will love your new investment. Clear Skies!

Stars in Spiral Galaxies

Spiral Galaxy M74

When most of us think of a galaxy we think of a beautiful spiral shaped entity. Astronomers have been studying these spiral galaxies for quite some time now, and have noticed that most of the stars seem be located within the arms. To form a star, you need a giant cloud of molecular hydrogen, and other gaseous materials. The cloud will eventually collapse due to gravity and form stars, and some of those stars may even host planetary systems. Most of the material in a galaxy (gas, dust, rocks, etc.) sits in the spiral arms in the plane of the galaxy. So it makes sense that stars tend to form here; it’s where all the stuff is!  Because the spiral arms contain millions of stars, they glow very brightly in optical light. This allows Hubble, and other telescopes, to image the structure of the galaxy. M74, pictured above, is a perfect example of a spiral galaxy whose structure is illuminated by the light from many stars within its spiral arms.

Image Credit: NASA, ESA, Hubble Heritage(STScI/AURA)-ESA/Hubble Collaboration 

Curiosity Self Portraits

I'm sure many of you heard about the Mars Science Laboratory: Curiosity in the news back in August. The rover successfully survived the trip and descent to Mars, landing safely in the early morning hours on August 6th (EST). Much of the scientific community was fretting about Curiosity surviving the landing due to all of the creative engineering maneuvers that needed to go of without a hitch for the rover to survive. Thankfully everything went smoothly and we are now beginning to study the Martian surface! A young girl, who has seen many of the photos the rover has taken, asked me why it keeps taking self portraits. "Why not point the camera at the Martian surface?" she asked. "We already know what the rover looks like. It's almost like he's taking a picture of himself for Facebook!"  There is good reason for Curiosity to take pictures of itself, and that is to make sure that everything is functioning properly. We want to make sure that nothing broke during Curiosity's trip, and we also need to make sure that camera, levers, wheels, etc. are all working as they should. Once we trust that everything is working properly, we can start to move the rover and do experiments. So we expect to see many more close ups of Curiosity on Mars, just as a sort of "check-up". Below is an image of almost the entire rover sitting on the Martian surface. Everything looks good to me!

Image credit: NASA/JPL-Caltech

Is Today Affecting Yesterday?

I came across an article this morning, that’s more about quantum physics than astronomy, but it was so fascinating that I just had to share it with you all. Physicists may have discovered a way that the future can alter the past! Yup, you read that right, what you do today could affect what you did yesterday! How can this happen? Quantum physicists are studying the ideas of non-locality and causality. Non-locality is the idea that two particles can be entangled such that an action on one automatically affects the actions of another. Kind of like two train carts tied together, if I move one the other moves as well. Causality is the idea that tiny particles exist with unknown properties until someone makes a measurement of one of those properties, and these measurements can be strong (I know for sure this is true about the particle) or weak (I think this might be true).

For example, lets say you glance super quickly at an unknown street sign, then look away. You might notice that the sign had a reddish color to it (weak measurement). You look quickly again, and notice there is also some white (weak measurement). Repeat the process and eventually you might figure out that you are looking at a stop sign. Then you stare directly at it for a few seconds (strong measurement) and for sure decide that it is a stop sign. The idea of causality states that the street sign’s properties are unknown (what type of sign is it?) and the signs location is unknown (where is it?) until you look at it and decide it’s a certain one in a certain spot. So how can observing an object properties today affect it yesterday? Try this thought experiment below

A friend and I live in Upstate New York, and we live 50 miles apart. You don’t know where exactly we live, but only that our houses are 50 miles apart and that our bodies are always 50 miles apart no matter what (we are entangles that way). Now you decide you want to figure out where I currently am. You can’t do this by calling or asking me, you have to put tiny bits of information together to figure out where I am (weak measurements). Ok, so you know that I just posted this blog, and therefore, I must be somewhere where there is wifi. You just made one tiny measurement of where I am, without defining exactly where I am. There are tons of place with wifi, so I could be at any one of those places. Measurement number 2, again I’m writing this blog post , so I must be at a computer (for the sake of argument, lets assume it must be a desktop computer). So now, with two measurements, you’ve narrowed down where I am (somewhere with wifi and a desktop computer), but still don’t know exactly where I am. Let’s pretend you were able to make a whole bunch of other measurements and finally figure out that I am at the local library, 10 miles from my house. Now that you’ve made a solid measurement of where I am, you have fixed me in place, and thus fixed my friend in a place exactly 50 miles away from me. Since I am 10 miles from my house, my friend must also be 10 miles from her house (because we are always 50 miles apart). But how did she get there? Sometime in the past, she must have drove from her house, to a point 10 miles away from her house. But we didn’t know or decide that she was 10 miles from home until we figured out where I was located, just now. The act of deciding that I am 10 miles from my house right now, put my friend 10 miles from her house, and thus altered the past in such a way that caused her to drive 10 miles away from her house sometime in the past. So my action of being at the library today, had an affect on what my friend did in the past, or in other words, the future (today or tomorrows actions) had an affect on what happened yesterday!

So what does this all mean? Are your actions today changing the past? Well, physicists aren’t really sure. They think they see this occurring for special particles that are entangled together and have certain kinds of properties. It doesn’t necessarily work on a human scale. But if we understand what’s going on in the quantum world, we may someday be able to use it in the “real” world…

Here is a link to a nice article explaining this in more detail: http://physicsworld.com/cws/article/news/2012/aug/03/can-the-future-affect-the-past

Discovery of the Higgs Boson!

Back on July 4th of this year, physicists working at the Large Hadron Collider (LHC) at CERN announced that they may have a found the much sought after particle called the Higgs Boson. One of the main reasons scientists built the LHC was to look for and hopefully find evidence of the Higgs. But what exactly is the Higgs boson and why is it so important?

To put it simply, the Higgs boson and the accompanying Higgs field are the reason why objects have mass, or in other words, why we take up space. For example, an astronaut in outerspace weighs nothing, as no large body is gravitationally attracting him. But the astronaut still has mass, he still takes up space. But what entity gives him mass, since it's not gravity that is responsible.  The theoretical answer to this is the Higgs field. Physicists think that a Higgs field pervades all of empty space, and Higgs bosons fill this field. When a particle enters the Higgs field, the Higgs bosons crowd around it, making it difficult for the particle to move and thus it feels heavy or massive. Think of it like a celebrity walking into a party. Everyone at the party crowds around the celebrity, making it hard for them to move through the room and thus they feel more massive. The Higgs field interacts with different types of particles in different ways, and the reason for this is not very well understood. But, if we have evidence that the Higgs boson does exist, then we can study it and hopefully answer this and many other questions associated with its discovery!

For a great explanation of the Higgs boson, check out this Ph. D. Comics movie!

Image Credit: Ph.D. Comics

Asteroid Eros as Real Estate?

Eros

Since the only other astronomical body that humans have set foot on is the moon, few laws have been put into place governing who can own what in outer space. Believe it or not, people have tried to claim full ownership of astronomical objects. A man by the name of George W. Nemitz actually tried to claim the near-Earth asteroid Eros as his property! Here's the story: Nemitz worked for a company which helped construct the Near-Earth Asteroid Rendezvous Probe Shoemaker, which landed on Eros in 2000. Nemitz claimed that since he helped build the spacecraft, he could claim ownership of whatever body it landed on, under the Homestead Principle. This principle states that if you discover a new piece of land that is not owned by another person or government (and I'm sure law makers were implying a piece of land on Earth), and you make use of it in some way, you can claim ownership. Thus, Nemitz dubbed Eros as a "spacecraft parking facility" and mailed NASA a $20 parking ticket for landing their spacecraft on "his" asteroid! Can you believe that? To Nemitz's dismay, NASA refused to pay the parking ticket, and a court judge dismissed his case. 

Image Credit:NEAR PRoject, NLR, JHUAPL, Goddard SVS, NASA

How Big is the Universe?

To put it bluntly, the universe is absolutely huge! The study of Cosmology, or how the universe was created and how it has evolved, has revealed some very interesting facts. We now know that the universe is expanding at an increasing rate, and that the universe seems to be roughly uniform. The approximate size of the visible universe is 10^24 miles wide! That's 1,000,000,000,000,000,000,000,000 miles! The image below represents what we believe the universe looks like. Every white spec in the image represents a galaxy, and there are over 350 billion of them! But notice how uniform it looks; there doesn't appear to be any distinct clumps of matter, its all equally spread out. This is somewhat expected  via the current cosmological theories, but also curious. Why should the universe be uniform? What properties of the beginning of the universe lead to this result, and how precise must they have been produce a uniform universe? Cosmologists are working hard on answering these questions, as astronomers continue to probe the most distant parts of the universe!

 Image credit: atlasoftheuniverse.com

Galaxy Superclusters

We live in the Milky Way Galaxy, a beautiful spiral armed galaxy filled with hot gas and young stars.

Did you know that many galaxies, including the Milky Way, actually formed in clusters? Galaxy clusters are groups of 30 or more galaxies that are all gravitationally bound to each other. Galaxy clusters nearby one another can form a supercluster of galaxies, though they may not all be gravitationally bound, just spatially coincident with each other. The Milky Way is part of the Local Group, which contains roughly 40 galaxies. This group is a sub-portion of the Virgo supercluster, which contains over 2500 galaxies within 100 million light years of us! These clusters contain spiral galaxies, like the Milky Way, but also elliptical galaxies which are disk shaped collections of older stars. Some popular clusters you may have heard of are the Fornax cluster, which also lies inside the Virgo supercluster, and the Coma cluster, which is a separate cluster of over 1000 galaxies located over 300 million light years from us. The image above shows some of the superclusters of galaxies in the Universe, with the Virgo cluster at the center. Each white dot is an entire galaxy, so those white regions throughout the image are collections of hundreds of galaxies! 

Image Credit: R. Powell

What Does An Astrophysicist Do?

Apologies for the hiatus in posts these last few weeks, life and work have been very busy. Since I've been swamped with so much work, I thought I'd take the time in this post to describe what  an astronomer or astrophysicist does on a daily basis.

When you think of life as an astronomer, the first thing that comes to mind is telescopes and star parties. You imagine the scientists out late at night staring through their telescopes and taking notes about what they see. While this part of the job, astronomers have much more to do. Graduate students and professors in astronomy spend most of their time teaching, doing research and applying for grant money. They teach or assistant teach college courses, and are constantly writing proposals to different organizations asking for money to fund their research. But what does "doing research" actually mean? In astronomy, research can mean one of three things: taking images with a telescope  and analyzing them using a computer (observational astronomy), writing computer programs to simulate interactions between objects in outer space (theoretical astronomy), or building telescopes, cameras, and detectors for astronomers to use (instrumentation). The first two require you to sit at a computer most of the day and  write computer programs to perform certain tasks. Observational astronomers also spend a lot of time applying for observation time on both space and ground based telescopes. If their proposals are accepted, they receive images from the telescope that they can then analyze to understand the physics and properties of the objects they are looking at. Theoretical astronomers are more like physicists or mathematicians.  They think of a situation that might occur in outer space, write down all of the physics equations  that govern the system, and write computer programs to simulate what's going on. Then they can compare their results with real observations to see if they are correct! The last group of astronomers spend most of their time in labs, building and testing devices for other astronomers to use. This is a more hands on job, and takes just as much engineering skill as it does astronomy knowledge. If it weren't for these people building nice cameras and telescopes, astronomers would be out of a job!

Aside from doing actual science, astronomers spend a good amount of time writing papers about their findings, doing community outreach, and presenting their work at conferences and colleges around the world. Being an astronomer is a lot of work, but also a lot of fun. It's a fast paced and never ending job, and there is always more to learn about outer space!

How Old is that Star?

Determining the age of a star is not as easy as you might think. Since we can't ask a star how old it is, we have to guess the stars age by its appearance. And just like with humans sometimes looks can be deceiving! 

 

There are many ways to determine the age of a star, and today we will discuss stellar models. Like we've discussed before, stars can be placed on an Hertzsprung-Russel (HR) diagram. To do this, you need to measure the stars brightness, or luminosity, and you also need to know what type of star it is. Is it a big, hot blue star,? A cool, small, red? Somewhere in between? Astronomers can determine this by looking at a star's spectrum, or distribution of light, with a telescope. Once we know these two things, we can place the star at the proper position on the HR diagram. Astronomers have been hard at work modeling how stars form, and how their size, temperature, and brightness changes as they age. They have developed paths or lines that are placed on the HR diagram which show a stars path on the graph as it ages. There are models for before the star has reached the main sequence, and after. Basically what you do, is place the star on the HR diagram, see which line it is closest too, and that tells you the stars size and age. Here is an example of how this works. The graph above shows brightness vs. temperature, and models (solid lines) for stars of different masses. Stars, in theory, follow one solid line path going right to  left as it ages. The star represents the spot on the diagram where some arbitrary star's properties are. Based on its position, the star is probably about 4 times the mass of the sun, and about 200,000 years old! This is before it has started hydrogen burning, and is still a "baby" star. You can follow the same method with different models and estimate the age of a star that is burning hydrogen, or on its way towards death.

Discovery of Uranus' Rings

We have discussed before that all the gas planets in the solar system have rings.  Even through a small telescope Saturn has visible rings, but Jupiter, Uranus and Neptune do not. So how did astronomers discover their rings in the first place?

Hubble image of Uranus and its rings

The rings around Uranus were discovered in 1977. Astronomers knew that Uranus was going pass in front of a distant star in the night sky, from Earth's perspective. They pointed their telescopes to towards the planet each night, and expected to see the planet block the light from the star only when the star was directly behind the planet. What they actually observed was the star flickering right before and right after is passed behind the planet. This meant that there must be some unseen object near the planet blocking the starlight! The only plausible explanation was that Uranus has very thin, dim rings that are not visible from telescopes here on Earth. In 1986, Voyager flew by Uranus and imaged the rings for the first time, proving  their existence. Since then, we have discovered rings around Jupiter and Neptune in similar ways.

NASA Missions Extended

 

Artists conception of Spitzer, Planck and Kepler (left to right)

Astronomers received some great news a few days ago. Three major space telescopes, Kepler, Spitzer and Planck, have had their missions extended! This is great news, as astronomers will obtain more data and hopefully make some big discoveries! But what can we do with these telescopes?

The Kepler Space Telescope is an optical telescope has been actively searching for exoplanets. It looks at the same region of the sky 24/7, and measures the brightness of 150,000+ stars. If one of them dims for a short period of time, it might be due to a planet crossing in front of the star and blocking the light. Kepler has already found over 2000 potential exoplanets in the last 2.5 years of operation, and it's funding has been extended until 2016

The Spitzer Space Telescope is an infrared telescope that has been operating since 2004. For the telescope's detector to work properly, it needs to be kept extremely cold. Unfortunately, the cryogenics which keep it cool have run out, but the detector still functions, and some science can be done with the telescope. Astronomers have used Spitzer to look at young stars, distant galaxies, and many other objects that are "hidden" behind giant clouds of gas.  It will continue to operate for another two years.

Planck is a jointly funded NASA and ESA telescope which has been operational for about three years. It's a space based microwave/radio telescope whose main purpose is the study the cosmic microwave background. This is the first light emitted by the universe after the Big Bang. It will help us understand how the universe began by observing it right after it was born. Astronomers also use Planck to study distant galaxies, and objects in our solar system.

Image Credit:  NASA/JPL-Caltech