Posts in Category: investigations
motion analysis: rolling
I love to do this lab or one similar to it in person, but you can also conduct an investigation about motion on your own. I’ve created some videos that you can use to collect data (and maybe these will inspire you to setup a situation from which to collect your own data) and I’ve also given you a little bit of video instruction to help out.
Here’s the basic idea: You want to figure out how to characterize motion, but all we can really measure directly is a position (“where”) and a time (“when”). We look for changes in these two things to describe motion.
I’ve just found a pool ball and a smooth table that the ball will roll on. (Like I said, you could do this as well, but it turns out I have a really nice setup for this.) You will want to compile some data about when (time) the ball is in different locations (positions). By getting this motion of the ball on video, you have the ability to repeat the same motion over and over and collect whatever data you need. In this case, I’m suggesting that you collect data for the time it takes to go from the start position of 0cm to another given position. I’ve marked increments of 10cm, so you can get the time it takes to get to the 10cm mark, the 20cm mark, the 30cm mark, and so on. The biggest distance I have marked on the video is 120cm. By replaying the video and running your stopwatch 12 different times, you can get 12 different data pairs of position and time.
I explain this here:
Then, you can jump into collecting data. Start with this video of the pool ball on a flat table. There’s two different versions of the motion, one in real time and the other in slow motion. Just pick one of these.
Like I said, you can pause and go back over and over, each time finding the time it takes the ball to go from 0cm to another mark on the table. Record those times with their corresponding positions in your notebook.
Then, you can do the same with this video of a ball rolling on a sloped table:
Once you’ve made all your measurements, your data can go into a spreadsheet or another table, and then from this you can create a graph. By tradition, and so that we can all compare our graphs to one another, your graph should have the positions on the vertical axis (“y-axis”) and the times on the horizontal axis (“x-axis”). So, a blank version might look like this:
But you’ll be filling this in with your own data. You can do this by hand, of course, but it’s also straightforward to have a spreadsheet (Excel, Google Sheets, etc.) make the graph for you as you input your data. To give you an idea of what I mean and to get you started, here’s a template for a spreadsheet that you can copy or download. You can then edit your own version to your heart’s content. I’ve set this up so that as you input data in the appropriate columns you should see the graphs form magically, all by themselves. You’re also welcome to change the settings for the graph, although I’ve tried to make it so you don’t have to.
Enjoy! I’m excited to see your data and the patterns your data create. You’ll be thinking about why it looks this way and we’ll talk about what this all means. Your assignment will tell you what I’m looking for in your report.
intro to hot chocolate
For your lab, you’ll be investigating what’s known as the “hot chocolate effect.” You don’t need to know anything about this effect and you certainly don’t need to try to look it up or read about it. (This usually just makes things worse.) Instead, take a look at my intro and then use this as a starting point for your own investigation:
Truly, I hope you always tap the bottom of your mug from now on when you stir hot chocolate.
(I created this other post for the general public about this effect, too. I think the effect worked better in this video.)
getting into the swing of data collection
One of our first tasks has been to collect some data on an object known as a “simple pendulum.” There’s no perfect simple pendulum, but instead this term is used to describe something that swings back and forth with all of its mass stuck to the end that’s swinging. A yo-yo swinging back and forth is a good example, or maybe a tetherball at the end of its cord; but lots of things are really close to a perfect simple pendulum. In fact, I was counting on the fact that you could find something that would work, likely right there in front of you.
Here are the instructions I gave for setting this up:
Then, you each collected data from your own objects: keys at the end of a lanyard, the adapter at the end of an electrical cord, a weight at tied to the end of a string, etc. These all work — though you might wonder if it’s okay to all be using different things if we’re going to share the data with one another. That’s a good question, and we’ll get to this.
After everyone reported data for the length of their pendulum and the time it took to swing 10 times, I took all of that and made a graph. Here’s an example:
I love this graph for a few reasons. First and foremost, you each collected ONE piece of data, and that single piece of information didn’t tell you very much. But now we have it in the context of all the other data. You can see how yours compared to others. More important, you can see if there are any patterns in these data. To me, it looks like there are. I tried to sketch some of what I’m seeing right on the graph:
MOST of the data show that the shorter strings take the least amount of time to swing, and the longest strings take the greatest amount of time. In addition, it looks like those times change most drastically when we change the shortest strings, and they change less for the longer strings. This makes a kind of curve that seems to be getting flatter and flatter as you go from left to right (shorter to longer strings). There’s a pattern here, and your data likely fits right into it. But we needed lots of these experiments in order to see the bigger picture. In fact, now we can even imagine that this curve could be described mathematically. Nature actually abides by this mathematical relationship — or maybe it even invents the mathematical relationship for which we needed to invent the mathematics!
For now, I’ll leave you with a few questions:
- Seeing that there’s a pattern here, what do you think a shorter pendulum would do? A longer pendulum? In other words, does this graph/pattern tell us about other pendulums we didn’t collect data for?
- I never told you to use a specific kind of object, so people probably used objects that had different masses (or weights). They probably also had bigger and smaller swings. Since we didn’t account for those variations, what might that mean?
- Not everything fits the pattern perfectly, and there are definitely a few outliers. Why? What do you think happened? What does this tell us about collecting data, conducting experiments, and creating investigations? Or, maybe more broadly, what does this tell us about science? Can we trust it?
raisins in soda
For some people in my family, there’s no good use for a raisin. I happen to disagree. I love them mixed in with nuts and candies, and I also discovered that they make for a great science investigation. When someone set aside all of their raisins, I decided to take video of what happens when I put them in soda water:
When you watch this, you probably have some observations, ideas, and questions. What makes the raisins go up and down? Why are some stuck on the bottom? Why doesn’t my family like raisins? For me, the more closely I look, the more questions I have and the more different things I’d like to try out.
While you’re thinking about this, here’s another video of the same raisins. This one is up close, and most of this video is shown in slow motion so that you can look really closely at some things going on.
You might want to look at this a few times closely, but maybe this is just the first step. If someone in your family doesn’t like raisins and shares them with you, maybe you’ll put them in a favorite drink and see what happens. There could be other liquids and other objects that could do similar things.
ice melting
On hot summer days you might really enjoy a glass with ice, just because you like a cold drink. But have you watched the ice in your glass up close?
I like investigations just watching ice melt. By taking some video and speeding it up, you get to see the whole process in just a few seconds. Here’s an example where we take ice that’s made from water with red dye. This way, as the ice melts you get to trace where that new liquid goes.
When you watch the ice melt, it’s funny that it goes from the top of the glass and falls to the bottom. What makes it do this? Why did it float in the first place? What would make it sink?
There are other liquids besides water that we can’t drink, but we can still put ice in them (as long as we’re very careful and label these liquids so we don’t accidentally put them in our mouths). I decided to compare what regular (water) ice does when it melts in water compared to when it melts in rubbing alcohol (isopropyl alcohol) that you can get at a pharmacy or grocery store.
Here’s a fast timelapse of these two, side-by-side. We think there’s a lot of interesting things going on, even at the beginning before any melting has happened. We added some salt at the bottom of the isopropyl alcohol to make it a little easier to see and to make some salt water as the ice melted.
I really enjoy making these videos because then we can replay these episodes really quickly and make comparisons. But it’s also great just to see how ice melts in different ways in real time. You could make videos; or, you could write notes or take pictures or just observe and talk to others about what you’re seeing. You might think of other variations on this theme.
light in gelatin
Some science investigations are especially fun to do at home. Playing with light and playing with jello are each great activities for indoors. This investigation prompt puts these two things together.
Here’s a video that I made at home, with no fancy lab or equipment — the perfect setting for most science-in-the-making. This is just to give you some ideas of where you can start, but there’s lots more you can play with and do.
In summary, all you need to do is make a gelatin dessert in your choice of flavor/color. Plain gelatin works great, too, but it doesn’t smell as good. When we make it, we just use half as much water (or don’t add any chilled water) and let the gelatin set in the refrigerator overnight. Then, cut out any shapes you’d like and put them on a surface like wax paper, a cutting board, or even just a clean table. Use a small flashlight or laser pointer to shine through the jello from the side, and observe what the light looks like as it goes into, through, and out of the jello. In my investigation in the video, I discovered some new things about how the light gets bent and focused; and I learned that my yellow jello lets through certain colors of light, but not others. I thought this was all really surprising and interesting, especially knowing that it was all caused by my 99 cent box of generic, lemon dessert.
Many other people do jello optics as well. Our friends at the Exploratorium in San Francisco showcase jello optics as one of their “science snacks.” Once you get started you’ll probably find other experiments to create on your own; or if you’re in a course I’m teaching you may be crafting lenses or other light bending and bouncing shapes with jello at home or in the lab.
looking up at the night sky
When the weather gets clear, it’s not only great for going out in the day, but also for going outside at night. There’s a lot of great science happening both during light and dark hours. In fact, observing dark skies is a scientific study all by itself!
Sometimes we take it for granted, but the reason why the sky is dark at night is not only because our side of Earth rotates away from the Sun, but because there’s a lack of other light as well. This tells us something about everything else in our Universe and how far away all sources of light must be and what they must be doing. (This is related to something called “Olber’s Paradox,” and it’s fun to read and think about, especially before you go outside to look at stars.) It’s also important that our own light from our neighborhoods and cities are not flooding our skies with their own light. If the canvas of the sky isn’t dark, then we aren’t able to see it contrast with dim stars.
You can measure how much extra light is in our sky by counting how many stars you can see — the more stars you see, the darker the sky must be. This is easier to do than you might think, and we’ve left some instructions below the break on this page that you can use to do this. You can compare your star counts on different dates and in different locations to see what happens to your star counts. We’ll record your star counts on this form as part of a project to analyze our dark skies locally. (Or, if you want to follow the instructions and only record the data for yourself, that’s a great project, too.)
If you’d like to share your data with an even bigger project, you can take a look here at the Globe At Night program . They have their own program and form to report your view of the sky by looking at specific constellations that they help you find. Then, this data gets compiled with other observations from all over the world. You can see some of their results here.
This is an exciting project for a few reasons. First, it’s a way to see how our own lighting affects what we see at night, which can have big implications that you might not even realize. The International Dark Sky Association shows examples from right here in Utah that you may have visited:
There’s a full list of designated “Dark Sky Parks,” here, and they include this gem in Weber County.
How familiar you are with the night sky, navigation, and even culture is dependent on being able to see stars against a dark background. But most of all, we think that it’s awe-inspiring to see a dark sky, maybe even with a view of our own Milky Way Galaxy stretched across the sky.
The first step to seeing any of this is simply to go outside in a comfortable place, let your eyes adjust, and look up on a clear night. Even if you do nothing else, just look up an imagine. You’ll start to see more than you might expect.
The other thing we love about star counting projects is that these are part of a larger collection of work called “Citizen Science” projects. These are scientific pursuits that you can help with by reporting your own data. Besides the Globe At Night program and the International Dark Sky Association’s own promotion of the program, there are completely different projects you can help with. We might highlight some of these in the future, but here are a few examples:
- Our own National History Museum of Utah features a collection of citizen science projects that could be especially relevantto you here in Utah.
- The projects showcased at Zooniverse extend more globally and even throughout the universe! (You can help categorize galaxies, observe ocean life, record migration patterns, etc.)
Whatever you do — even if it’s just for yourself — recognize that the observing and appreciating is a big part of how science gets started. Let us know what you start to see, and let us know if you have questions along the way!
Instructions for counting the stars in your sky
On a clear, dark night, go outside at a location of your choice — your backyard is great — and count the stars! Instead of counting all of them, however, you will count them as you look through a toilet paper tube. (Maybe this is why people are buying so much toilet paper these days?)
After your eyes are adjusted to the dark, hold the tube to your eye and point it in a random direction and count how many stars you can see in that part of the sky. This is a sample of the sky. Do this 8 times, each time pointing in a different, random part of the sky. Write down your counts so that you can analyze them when you go back inside.
Once back inside, you can also get your location’s approximate star count by:
- Adding up your 8 counts all together, and then
- multiplying that sum by 9 (assuming you use a toilet paper tube, because this factor describes how much of the sky you were sampling with this device).
For comparison, if you had a completely dark sky and well-adjusted eyes, you could be able to see almost 5000 stars with the unaided eye. How did your measurement compare? How do you think it would be different in different locations? (You should try other places , too, when you have the chance!)
You can also do more research on dark skies and light pollution. A good place to start is here:
where the International Dark Sky Association provides other information and tools for doing more star counts. They also describe why this is an important issue — but you might think about this yourself before you read more.
hot chocolate effect
We often imagine that good science is the kind of thing that studies the dynamics of distant stars and a cure for disease. Sure, it does work on these big problems. But it is just as focused on and important to our everyday experiences.
Here’s my prime example. This is me at home, stirring some hot chocolate. It turns out that hot chocolate can demonstrate a very novel effect that you probably have never noticed even if you’ve stirred hundreds of mugs of the beverage. Once you realize it’s right in front of you, you may be forever cursed/blessed with the tendency to tap the bottom of your mug after you’ve stirred the chocolate in.
My hope is that you would want to try this out and think of ways to investigate what’s going on. If you’re in one of my classes, you’ll probably be given this as an assignment or even as the subject of an entire lab. You would consider trying out variations to see if you can find what causes the effect: What if you used something other than hot chocolate? Or different kinds of hot chocolate? Or different mugs? Or other ingredients? By changing the conditions, you might start to narrow down what makes this effect. At the same time it can be really challenging, because changing one variable could change another; and sometimes we don’t even recognize when a variable is changing.
Something I like about this investigation is that it naturally makes you consider your own model about sound and the hot chocolate. When you decide to change something in this system, you naturally have some idea about why that may or may not work, and it’s based on what you’re imagining is happening in the hot chocolate and how you might think that sound works. The results of your test affect your model and give you insight into what test to try next. This is, in essence, how science works.
Studying the hot chocolate effect is one of my favorite science investigations in the whole world. I introduce it to students, teachers, and scientists whenever I can because:
- Once you have experienced the effect, you may be forever cursed/blessed with tapping your mug of hot chocolate to hear this phenomenon, and you hopefully will share it with anyone else around when you are enjoying your beverage. You may even start investigating the effect by honing in on specific variables and testing specific conditions.
- We often think science is about warping space and curing disease. And that’s correct, but those are just a couple of examples. Scientific pursuits are at hand in all kinds of scenarios, and sometimes you just have to look a little more closely. You might have stirred hot chocolate hundreds of times and never noticed this.
- Also, people–especially scientists–often think they know the explanation for this right away. They usually don’t. (I’m speaking for myself as well.) And why should they? There’s a lot going on here, and we should embrace not knowing right away. Simply diving into this human endeavor of science is something we should celebrate.
- And even when you understand an “answer” to this, it usually isn’t finished. One “answer” just leads to more questions, and this effect is a prime example of where this can lead you down lots of rabbit holes.
Enjoy your hot chocolate, and your science.
bubble observations
This narrative describes our first task.
Walking into a first day of a science class, one of the proclamations that we’re conditioned to hear is about the power of the “scientific method.” There are plenty of first chapters of textbooks that devote themselves to describing a bit about what science is for, how it’s both an extension of things we naturally do, and a sharp contrast to other ways of knowing. And then there’s that scientific method. Each text is a little different on this point, but the essence is that we root out truth by testing our explanations against what we actually observe.
But I think we need to start somewhere else, back just a bit. I’m not sure that we really always agree on what it means to “observe.” And, it’s probably good to actually put this into practice. Observation is like any other skill.
For me, a sensible introduction to physical science is to begin with soap bubbles. This could be with a sink full of water and some dish detergent, or it could be some canister of stuff that you have left over from a summer birthday party. There are a few recipes that I like, but the basics of any of them include about 12 parts water and one part simple dish detergent. Put a wand, a straw, or even the end of a pipe or funnel into the solution so that a film stretches across one end, and then blow through the other.
What do you observe?
Get out your science journal. This could be a simple composition notebook, lined or unlined in any fashion you like. For me, the important part is that it’s a notebook that accompanies you and records ideas, observations, questions, and pursuits that may or may not lead to anything else. It’s not necessary that it’s pristine or even particularly well organized. You can display your edited genius in some other way, but this should be something that’s flooded with mistakes, ramblings, and snippets of ideas. It’s your blueprint of potential.
Find a page to start and document bubble observations. Having a partner in this pursuit is useful, not only because one person could be blowing the bubbles and the other could observe something closely, but because one person’s observation can lead to another. That said, there’s something about just sitting with an observation all to yourself. It’s up to you. (Often I’d have you start this in class, with a partner; and then you’d head home armed with your notebook and your bubbles to do more observations yourself.)
One of my favorite photos is this one of a girl playing with a giant soap bubble.
What do you observe?
It’s a good example of the many things that we could find in a soap bubble if we look closely. First, there’s the bubble itself, stuck to her hands. There are colors that are rainbow-ish, but not really the same colors that you see in a rainbow. Then, looking a little more closely, there’s a reflection of the sun at the top of the bubble, as well as another at the bottom of the bubble. There’s a big drop of bubble goo starting to form at the bottom, too. And there are hands — not just those holding the bubble, but reflected images of those hands at different places. Look some more and you’ll see that the photographer is in this image as well, reflected back from the front surface, his camera and hand towards the center, his legs and feet at the bottom. Each time I look at this image, I see something new.
Your first observations might be about how the bubbles form, how they fall or drift, what they do when they hit the ground, how they interact with one another, and on and on.
Keep observing. There’s no rush, and there’s plenty to see.
_____
The following essay, written by Samuel Scudder, was about his first experience in graduate school. He showed up to essentially begin his apprenticeship as a research scientist, ready to study insects. His professor greets Scudder and tasks the student with observing, of all things, a dead fish.
The Student, the Fish, and Agassiz,” by Samuel Scudder (1879).
Give this a read and consider what’s happening to Scudder and how he’s learning to observe. Go back to your own bubbles, again, and observe as Scudder might recommend to an apprentice scientist.
Go ahead, I’ll wait.
_____
What kinds of things do you observe with the bubbles now that you didn’t see before?
In general, we see more details that might seem more elaborate; we might take a pencil (like Scudder did) to start to observe through writing and drawing; and it might occur to you for the first time to note that the bubbles are round, just like fishes are symmetrical.
It should be no surprise that Scudder wasn’t the first nor the last person to observe a fish. Here’s another account:
“The Fish”, by Billy Collins (as published in the New York Times, along with some recipes)
Billy Collins is a notable poet, holding the position of U.S. Poet Laureate from 2001 – 2003. His observation of a fish is quite different — and not just because he’s at a restaurant in Pittsburg, although that’s clearly part of it.
Consider the perspective of a poet. Go back to your bubbles and observe again, still using that notebook, but now looking through the lens of a poet or perhaps even another artist. You don’t need to write your own poems (though no one is stopping you). Just observe from this new perspective.
Now, what do you see?
_____
The point of this exercise is two-fold:
First, observation is something that we take for granted as a practice and a skill. It’s at the very heart of what science does, where it starts. We don’t come up with questions or investigations or models or anything else until we’ve experienced phenomena in some way. Sometimes, the experience is in the mind’s eye, constructed from other things that we know, like with something as exotic as a black hole. Most of the time, though, I suspect that we start with an observation that’s very simple, seen but unobserved until we take the time to really delve into it.
Second, “observation” isn’t an action without context. The observations are different and differently directed if we look at something as a scientist rather than as a poet. As a scientist, we look for patterns that lead to an understanding of how things are put together, why they might move the way they do, how they function. As poets, we probably associate other meanings with what we see. Empathy and metaphors, statements about the human condition and how we can relate these to one another — these are all outside of scientific reach, but they’re still valuable in their own way and with their own purpose. The work of the scientist might impact the work of the poet (or the painter or the philosopher or the writer or anyone else), but it’s important to be clear about which of these lenses we’re wearing. Throughout this course, we’ll refine the lens we use as scientists, but this doesn’t mean the other lenses are less valuable. They just have different goals.
Astrophotography
Note: This is just a quick tutorial on astrophotography. For other astronomy resources, take a look at this collection I’ve been compiling. (And let me know if there’s something more that you are looking for.)
Disclaimer: I’m not an astrophotography expert. I just get the basic idea and I like to mess around with this. I think that astrophotography is easier than working a telescope and in many ways it’s more immediately rewarding. It also gives you something fun to play around with on even modest cameras. As long as you can keep a shutter open for a few seconds, you can do astrophotography.
You can read my basic description below. In addition:
- You’re welcome to pull up this Astrophotography Presentation that I use for workshops.
- Here’s a collection of photos taken by people at one of these workshops.
- There are plenty of other tutorials like this that are more detailed than what I’m providing here.
- Many of us carry phones around not for calling people but for taking pictures. They aren’t ideal for astrophotography because they have small sensors and apertures, but there are some apps that can add multiple exposures together. Here’s one example that I’d like to play with more.
Here’s the basic idea. The stars are very dim from our perspective, since we’re really far away from them and their light is spreading out and sharing that energy all over space, limiting us to only a small fraction of that. In addition, the amount of light collected by your pupils is really small, both because the opening collecting the light is really narrow and because your eye sensors are refreshing what they’re detecting several times per second. Also, your detection system, the retina with its cones and rods, has a limited sensitivity. With a camera, you can adjust these factors. The display on my camera looks something like this for a “normal” photo:
And, it would look something like this for astrophotography:
There are adjustments that can be made for the amount of time that the shutter stays open, and for stars I generally want to adjust this to something like 5 seconds to start, depending on the camera and the conditions. Most of the time that you take a photo in daylight, the shutter stays open for a fraction of a second. Also, I should open up the aperture as wide as possible in most cases. In camera-speak, this means you should make the f-stop be a number that is as small as possible. And, I probably want to play with the sensitivity of the camera’s detector, what’s known as the ISO. (Back in the old days, we used film that we’d say was a certain “speed,” but that was really a measure of the sensitivity of the chemicals in the film.) This is tricky because as you increase the sensitivity, you also allow for a grainier and perhaps even noisy looking background, which is exactly the opposite of what you want in astrophotography. Also, the measure of ISO is something that seems to change with each generation of cameras, and using really high sensitivities on a camera made in the last couple of years would have been unheard of just a few years previous. So, start with something and see how it turns out. For me, I have a 35mm lens (fixed focal length) that I can open up to f-1.8, and to start I’ll open the shutter for 5 seconds and use an ISO of 1600. (I use a Nikon D5300, in case that’s relevant to you.) After that I’ll just play around. If there’s a lot of light pollution, this will be way too long and the photo will be washed out. If I have dark skies, this will show wide variety of stars with a still dark background.
There are a few other important pieces. First, if you’re going to leave the shutter open for several seconds, you need the camera to be absolutely still. A sturdy tripod is important for this … or so everyone says. Honestly, I’ve used a bag of marshmallows propped on a rock with a smaller camera positioned just so, but on the other hand I’m not getting award winning images with that technique (unless it’s in a special marshmallow-propped category). Use what you have and see how it goes. But, probably the most violent time for the camera is when you’re pushing the button to take the photo. So, especially if you don’t have a good tripod, try a setting that makes the camera trip the shutter a few seconds after you’ve pushed the button, or perhaps use some kind of remote shutter button. (More and more often, there are ways to connect your phone to a camera over bluetooth or wifi.) You’ll find these options on most cameras under some menu that gives you choices for delayed shots like this, as well as for rapid-fire exposures. Finally, you need to focus on the stars. It seems like this should be easy, but I see mixed results with every camera I’ve played with. Stars are practically an infinite distance away, so you should set your focus, manually, to infinity. (Autofocus probably won’t work because there’s so little for the camera to “see.”) This always seems to be just a touch off for me, so my suggestion is to play around with it. Most of the time I use the viewfinder while pointing at a distant object on the horizon and get it as sharply focused as possible and then just leave the focus there. Stars that are in focus will look like sharp points. They shouldn’t have any significant diameter to them (unless they’re planets). Depending on your camera, you may find other focusing strategies as well. Some cameras have a digital control of the manual focus, and you can actually select “infinity” on the focus control screen.
I’ve compiled a few modest photos with a compact camera, but here’s one that I think is a good example of what you can do with a simple point-and-shoot camera (before I had a DSLR):
This is one of those photos that was taken from the hood of my car with a table-top tripod. With this photo, you can clearly make out the Big Dipper (centered, bottom third of the frame) and the double star in the handle. Above that you can make out the entirety of the Little Dipper, something that’s hard to do with the naked eye except with the darkest skies. And, at the bottom of the photo you can see a streak of fire-like light. This is actually the tail lights of a car going by, which gives you a sense of the exposure time for this photo.
Here’s a very similar field of view, but taken from a darker location in the Uintas. If your monitor if bright enough, you can make out the outline of trees that block the stars behind.
And finally, here’s a photo taken during a workshop with local teachers. This tripod was set right here on the observatory roof of Tracy Hall Science Center at Weber State. Looking north, we were able to pick up Cassiopeia, a streak from a satellite, countless other stars, and even the Andromeda Galaxy. The light from the latter is 2 million years old! (You can find a full resolution file in the original gallery.)
