Archive for the ‘Not Mars’ category

HP dv6t Select Edition Notebook Review: First Impressions

July 24, 2010

Please excuse me while I geek out about my new laptop…

My work now involves some really significant number crunching, to the point that I was regularly using all the CPU and RAM of my previous laptop, and was then struggling to get anything else done while the calculations were running. And then they would crash. It also helps that I will soon need to renew the license on one of the programs that I use, and the student price is only available for a given CPU once. And of course, there’s a game coming out on Tuesday that I really wanted to be able to play.

I decided from the outset that I was going to aim for a high-end system this time. I spend a ridiculous amount of time in front of my laptop, for both work and fun, so I wanted a quality machine. After lots of web-searching and comparing, I decided on the HP dv6t Select Edition. It had impressive specs, and there was a $400 coupon to sweeten the deal. Here are the full stats:

  • Processor: Intel Core i7-840QM processor (1.86GHz, 8MB L3 Cache) with Turbo Boost up to 3.2 GHz
  • Windows 7 Home premium 64 bit
  • Hard Drive: 500 GB 7200 RPM
  • RAM: 8 GB
  • Screen: 15.6″
  • Resolution: 1366×768
  • Approximate weight: 5.5 lbs
  • Graphics: 1GB ATI Mobility Radeon(TM) HD 5650 Graphics + HDMI and VGA ports – For Quad Core Processors

The computer arrived on Thursday, so I’ve had a little time to get it set up and get used to it. Here are my first impressions:

First of all, this is the sexiest computer I’ve ever owned. I really like the (mostly) metallic case and the subtle texture on the lid and hand rests. I saw somewhere that similar HP designs had a “pinkish” hue to the metal, but the dv6t SE definitely does not.The computer also feels solidly built, with no “wiggle” in the screen hinges and no flexing when picked up by the corner.

Click for a closer view of the lid texture.

Also, I love the “chiclet” keyboard. It just feels good to type things on it, and it is big enough that I don’t feel cramped at all. If you’re considering this laptop, I highly recommend paying the $25 more for the backlit keyboard. I didn’t realize how useful this feature would be, but I have used it quite a bit.

I do have a few complaints. The biggest problem is the track-pad. For some reason, HP decided to forgo having separate buttons to click and instead made the lower left and right corners of the track-pad clickable. This would be ok, except that those areas also still work as a tracking surface. When I’m using the track-pad I like to have one hand pointing and the other clicking, but this doesn’t work so well when the buttons also act as the pointing surface. Also, you have to push the corner “buttons” down a lot harder than I’d like. The track-pad is also supposedly multi-touch sensitive. I haven’t played with this feature much, but have found it to be pretty unresponsive and therefore useless for scrolling around web-pages and documents.

The trackpad is the worst feature. Click to see its weird all-in-one buttons and the nice texture of the hand-rests.

Basically what I’m saying is that if you get this computer, be prepared to use a wireless mouse. That’s what I normally do anyway so the trackpad is not that big a deal for me.

Another very minor complaint is the row of keys on the far left side of the keyboard. I am used to the control button being the lowest left one, but on this laptop, to the left of ctrl is a button that brings up a calculator program. I find myself occasionally hitting the wrong button and having a calculator pop up instead of, say, copying text with ctrl+C.

One other downside is that it does come with quite a bit of HP crap-ware. But most computers come pre-loaded with software that you’ll never use. Once you get the worst offenders uninstalled or at least turned off, it’s fine.

I really like the keyboard, though I sometimes hit the calculator button instead of Ctrl.

Other factors that might be a problem for some users are heat and battery life. I sprang for a very fast Intel i7 Q840 processor, which puts out a lot of heat when it is working hard, and eats up battery life. I haven’t formally tested the battery, but I wouldn’t count on more than 2 hours. Again, that’s not a big deal for me because I almost always use my laptop near an outlet. And my previous laptop’s battery life had dwindled to about 7 minutes, so this is luxury for me! There is a larger battery than the one I have, so there’s always that option if you’re considering this laptop and want more battery life. The computer itself is very sleek but I was surprised at how chunky the power adapter is. Both the cord and the brick are pretty hefty. Again, this might be an issue for some but not a big deal for me: I’m used to my slightly-heavier Toshiba with a less-bulky AC adapter so the total weight will be similar.

Here's a close-up of the light-up HP logo and texture on the back.

Coming back to heat: yes, this computer runs hot. For normal use it’s warm but not uncomfortable to use on your lap, but if you’re doing anything CPU-intensive, this computer (and any notebook really) should be on a hard surface to allow plenty of air-flow. When I was running work programs, it got mighty toasty.

But holy cow is it fast. It’s noticeably zippy at basic usage tasks, like installing and opening programs, but what really blew me away was using it for work. Not only is it faster, but since I got the 64-bit Windows 7 with 8 gigs of RAM, it easily was able to load my entire dataset for work without breaking a sweat. My previous laptop had to break the data into chunks and half the time would crash if I tried to load too much of it at once.

Bottom line, I am really loving this computer. It looks and feels really nice and has awesome performance to match. The only major downside is the trackpad, and I typically use a mouse anyway so it isn’t a big deal for me. There are some other nitpicks, but overall it is very nice. If you’re looking for a powerful, good-looking notebook computer, I recommend the HP dv6t Select Edition. Especially if you can find any special offers from HP (the coupon I used has expired, but they seem to do a lot of coupons, so look around if you’re considering buying from HP!)

And finally, here is a view of the bottom, which is black plastic rather than metal. I had a hard time finding bottom views when I was shopping for laptops, so hopefully this will be helpful for others:

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The Science of Starcraft: Creepy Slime Molds

July 23, 2010

My second article is up over at my new Science of Starcraft blog! This one is about the weird substance in the game called “creep” and its similarities to real-world slime-molds. Check it out! Even if you don’t play Starcraft, slime molds are really cool/weird.

(PS – I swear I’ll be posting some real Martian Chronicles content soon instead of just pointing to articles elsewhere! But I’m trying to get the Starcraft blog on its feet before the Starcraft 2 release date next week, so I’ll be using this blog to publicize it a bit.)

Branching Out

July 5, 2010

I have a confession to make: sometimes I don’t feel like posting about space. I know, this a shocking admission from a graduate student in Planetary Science. After all, grad students are supposed to live and breathe their topic of interest, right? Well, I still am really interested in space, but I’m also really interested in other stuff. For a long time now, I’ve struggled with the sometimes conflicting goals of posting stuff to the blog and posting stuff that I happen to think is really cool and interesting at the moment. For example, I’ll read a good fantasy novel that I want to tell people about, but then I’ll think: “But the blog is supposed to be about space exploration, isn’t it?” And then it doesn’t get posted.

It’s entirely possible, and I daresay likely, that you, my loyal readers, wouldn’t mind reading about non-space stuff if I posted it. But I’ve always felt a little guilty about straying from the nominal topic of the blog. Well, no more of that. With this post, I hereby give myself permission to post about whatever I please. This is the Martian Chronicles, not the Mars Chronicles, and this Martian sometimes wants to chronicle more than space news.

I’ll still post about space, of course. But don’t be surprised if you see an uptick in posts about other topics, especially sci-fi, fantasy, writing and other sciences.

What is the Best Dinosaur?

June 25, 2010

This is the funniest, most well-informed rant about dinosaurs I have ever witnessed (warning, NSFW language). I was a dinosaur freak as a kid, and I still remember a ridiculous amount about them. Can I just say how much I loved watching him shoot down people who thought plesiosaurs and pterodactlys were dinosaurs? Everything he says is correct except for one thing: Brontosaurus was (I believe) either a diplodocus head or a model of a head (no skull was ever found) on an apatosaurus body.

This picture of a Utahraptor is a combination of the scale drawing and artist's rendition on Wikipedia.

His rant about raptors is almost correct, but the velociraptors in the movie are actually a bit smaller than the real-world Utahraptor, which he mentions in passing. Deinonychus was about 4 feet tall, and was awesome until Jurassic Park came along. And yes, the real Velociraptor was about the size of a goose. Around the same time as the movie, a novel called Raptor Red came out, about a Utahraptor. I loved that book. It was written by a paleontologist (Robert Bakker), and brought the cretaceous to life for me.

Anyway, my vote for best dinosaur is the Utahraptor. Intelligent, social, fast and strong, and the real inspiration for the “velociraptors” in popular culture. Also? Probably warm-blooded, had feathers, and is closely related to birds.

What’s your favorite dinosaur?

Solar System Tour: Mercury

May 31, 2010

Mercury is the smallest planet in the solar system. It is 4,879 kilometers across. Compare that with our moon, which is 3456 km across, and you can see that Mercury is not very big. In fact, Jupiter’s moons Ganymede and Callisto and Saturn’s moon Titan are bigger! Even though those moons are bigger, Mercury weighs a lot more than they do because it is made of mostly metal and rock. In fact, Mercury has the most metals for its size of any planet in the solar system. Mercury is also the closest planet to the sun: it goes around the sun in 88 days. Mercury rotates on its axis (like a top) two times for every three times it goes around the sun. This means that days on Mercury are really weird! Since it rotates so slow and goes around the sun so fast, if you were standing on the surface of Mercury (I wouldn’t suggest it!) you would see the sun rise in the east for a while, then dip back down towards the horizon, then zip over to the west to set! The sun would be above the horizon for about 60 days. Check out this great simulation of a Day on Mercury to learn more.

Notice how the sun is slightly off-center because Mercury's orbit is more elliptical than most.

Mercury has an unusual orbit. It is more elliptical than most planets, which means it is more of an oval. For a long time, nobody could quite explain the way that Mercury orbited. Many astronomers thought there might be a smaller planet even closer to the sun that was tugging on Mercury and making its orbit disagree with their calculations. It turned out that they weren’t using the right physics! When Einstein came up with his theory of General Relativity, which was an improvement on Newton’s law of gravity, it gave exactly the right answers to explain Mercury’s orbit!

Mercury’s elliptical orbit means that its distance from the sun changes a lot. At the closest, it is 46 million kilometers from the sun. At the farthest point, it is 70 million km away. Even though the distance changes, no matter where it is in its orbit, Mercury is pretty darn close to the sun. On the daytime side, the temperature gets up to 400 degrees C (752 degrees Fahrenheit!). On the night side of the planet, the temperature falls down to -170 degrees C (-274 degrees F). That means that during the day on Mercury, a block of lead would melt into a puddle, and at night it is almost cold enough for oxygen to be a liquid (-182 Fahrenheit)!

Mercury is one of the rocky inner planets. It has a crust a lot like the earth, except mercury is not as geologically active. This means that the crust you’re seeing has not been “recycled” by erosion, volcanos, or plate tectonics. Below the crust is probably a mantle hot, almost-melted rocks. Because mercury is so heavy for its size, scientists think that it has a very large, metal core. By carefully studying how Mercury spins, scientists have figured out that Mercury’s core must be at least partially liquid.

Mercury is one of the most cratered objects in the solar system. The more craters something has, the older its surface is. (What does this tell you about the Earth’s surface?) You can also tell which craters are older than others. If there are craters on top of another crater, the one on the bottom is the oldest. Also, “fresh” craters have bright streaks coming out of them. These bright rays are debris that was blown into the sky when the crater was formed, and then fell back down onto the planet.

The largest crater on Mercury is called the “Caloris Basin”. This huge crater is 1300 kilometers (800 miles) across! It shows up clearly in this false-color view of Mercury:

Caloris means “heat” in latin. The basin got that name because it is near the place on Mercury that is pointed at the sun when the planet is closest to the sun. That means it gets really hot! The shock waves from the giant Caloris impact were so strong, that on the other side of the planet, the ground is all wrinkled and bunched up.

Until recently, there had only been one probe sent to Mercury, Mariner 10. It only got a chance to photograph half of mercury’s surface. For a long time, half of the planet was a complete mystery. But a probe called MESSENGER flew by Mercury a few times recently and took some beautiful pictures to fill in the missing information. It will go into orbit around Mercury in 2011, and we will finally be able to study mercury in detail!

A photograph from one of Messenger's flybys of Mercury.

Solar System Tour: The Sun

May 28, 2010

Everyone knows about the sun, it’s that really bright thing that rises every morning and sets every evening. Not everyone knows much about it though. For example, did you know the sun is actually a star? Ok, so maybe you knew that. But if you’re so smart, what’s it made of? The sun is almost entirely hydrogen, with a bit of helium mixed in and a tiny amount of all the rest of the elements, just to spice things up. You might think that a bunch of gas floating around in space wouldn’t hold together very well, but the sun is HUGE! It weighs 300,000 times as much as the earth! Because it is so big, gravity holds it together very nicely. In fact, gravity squeezes the center of the sun together so hard that the hydrogen atoms stick together to form helium in a process called fusion. Here’s a diagram of what happens during fusion:

It looks sort of complicated, but the important thing to know is, four hydrogen atoms get turned into one helium atom, and in the process a LOT of energy is released. All the energy being released in the center of the sun has to go somewhere, and it goes into heating up the center of the sun. The center of the sun is 15 million degrees Kelvin (that’s 27,000,000 Fahrenheit!!)!

At really high temperatures, matter is no longer a solid, liquid, or gas. It becomes a plasma, which means the electrons aren’t attached to the nucleus anymore, and both can just go flying around. Energy from the core of the sun makes its way toward the surface in two ways. The first is radiation, which means it travels as photons (light) through the dense plasma. After traveling by radiation for a while, the energy starts to travel by convection. Convection is what happend when you heat a blob of gas. Hot gas is less dense, so it starts to float upward. Once it floats to the top, the hot blob cools down and begins to sink again. This rising and sinking is called convection. Convection is what causes weather on earth, hot air rises and cooler air rushes in beneath it, making wind. On the sun, we can see convection happening right at the surface. The blobs of hot plasma are called granules. Each granule is about 1/10 the size of the earth! Check them out in this picture:

The bright parts in the center of the granules is hot gas rising, the dark edges are the cool gas sinking back down. This layer of the sun (with all the granules) that you can see is called the photosphere. It has an average temperature of about 5800 K. Most people think of the photosphere as the “surface” of the sun. Above the photosphere is a thin layer called the chromosphere. You normally can’t see this layer because the photosphere below it is much brighter, but sometimes when the moon passes in from of the sun and blocks most of the light (a solar eclipse), you can see the chromosphere glowing red. (Never look directly at the sun, even during an eclipse!!) The chromosphere is hotter than the photosphere, at around 7000K. At this temperature, hydrogen glows red, giving the chromosphere its color.

Above the chromosphere is a wispy layer that extends off into space called the corona. The corona is really hot (more than a million degrees!) but not very dense. It is made of gas and bits of atoms that are getting blown off the sun. These particles are called the solar wind. When they hit the earth’s atmosphere, they make the very highest layers of air glow, causing the northern and southern lights (also called aurora). Telescopes have shown that Jupiter and Saturn also have aurora, so the solar wind keeps going a very long way.

Spots and Loops and Flares, Oh My!

The sun isn’t just a boring ball of plasma, there’s some really amazing stuff going on up there. We said before that plasma is when the bits of atoms can move around however they want, but that’s not the whole story. When things that have a charge (like electrons and protons) start moving around, they create magnetic fields. Those magnetic fields force the plasma to follow them, and end up making some really interesting features on the surface of the sun. Sunspots are the most well known result. What happens is, a bunch of magnetic field lines cluster together and keep the blobs of gas from convection from rising up in that place. The gas that is in the sunspot gets stuck and cools off, so it looks darker. Check out this movie of sunspots forming! (Note: Unfortunately all the movies in this post are .mov format, which I can’t embed. But they are truly awesome, so I recommend clicking the links!)

The powerful magnetic fields on the sun force the plasma to follow them, and make beautiful glowing loops that extend into the corona. The loops can grow to be extremely large. When they are seen in front of the photosphere, they are called filaments, when they are seen at the edge of ths sun in front of space they are called prominences.

These loops contain a lot of energy stored in the magnetic fields. Sometimes the filaments “let go” and plasma goes flying either away from the sun, or is attracted to other magnetic fields on the sun. Check this out! A blob of gas goes flying off and hits some loops, making them shake back and forth. Sometimes, when the loops get crossed or twisted, a huge amount of energy is released in what is called a flare. During a flare, a patch of the sun heats up VERY quickly because of all the energy released. Sometimes this causes huge clouds of hot gas to go flying off the sun.

These clouds of gas are called Coronal Mass Ejections, and can be enormous! Check out the next picture, with a picture of the earth added for scale.

MarsSed 2010 Field Trip Day 2: Stromatolites, Gypsum and Layers

April 29, 2010

We started off Day 2 of the field trip by driving up onto the eroded rocks of what used to be the tidal flats of the ancient reef, between the shore and the continental shelf. The closest modern-day analog to the rocks that we visited is the Persian Gulf, where you have an arid climate and deposition on the shelf and down into the deeper ocean basin. In the tidal flats and lagoons of the ancient sea where the rocks that we visited formed, the water was only a few meters deep, and was a nice place for blue-green algae to grow. You might think that a bunch of single-celled organisms wouldn’t leave much of a mark in the geologic record, but you would be wrong!

The wavy layers in the carbonate rocks here are stromatolites - fossil backterial mats that grew in the shallow tidal flats and lagoon behind the ancient reef.

In fact, cyanobacteria growing in tidal flats tend to form thick, wavy mats that are then preserved and fossilized, forming “stromatolites”. Stromatolites are among the oldest evidence of life on the Earth. We spent quite a while discussing the stromatolites here, and particularly learning how to tell the difference between wavy layers that are biogenic and those that are due to things like sand ripples or deformed layers that were originally flat. The variation of the layer thickness is the first hint: stromatolites tend to be thicker in low points and thinner in high points. If the waviness was due to the deformation of originally flat layers, there shouldn’t be a change in thickness between highs and lows. Another hint is if you can tell that the waviness forms domes rather than parallel ridges, and especially if you find isolated domes or columns. It’s difficult to form an isolated dome-shaped ripple, but that’s exactly what you get when mounds of cyanobacteria are growing.

Modern stromatolites growing in Shark Bay, Australia. Original image by Paul Harrison.

After looking closely at stromatolites, we drove closer to what was the ancient shore and encountered an abrupt transition to layered gypsum and silt beds deposited as the near-shore pools periodically dried out. This area was used as the “slow-motion” field test for Mars Science Laboratory in 2007. The science teams essentially practiced by sending someone out here to take pictures and samples, and the team tried to understand the site without any other information. For our field stop, we took a look at some infrared maps of the minerals in the area, and then climbed a nice exposure of them.

We climbed "Tepee Hill", a nice exposure of gypsum and mudstone layers deposited in the evaporative shelf lagoon.

In the afternoon, we drove to “Last Chance Canyon” to admire an excellent exposure of the inclined beds that characterize the transition from the continental shelf to the ocean basin. The curves of the canyon let us see the tilted layers from different angles to get a good three-dimensional feel for the stratigraphy. We spent a while sitting up on one side of the canyon and sketching the opposite side and then hearing from our expert guides about all the subtle details that we amateurs had missed in our sketches.

The upper layers here are flat-lying, but below them, the layers begin to dip down to the right. These dipping beds were deposited on the slope of the shelf margin. Don't be fooled by the diagonal dark green vegetated stripes that go from upper right to lower left - those are fractures in the rocks where plants have taken hold.

It started to rain while we were studing the outcrop, but lucky for one member of our group, he was carrying the large canvas print-out of the Burns formation, a well studied section of rocks on Mars. Turns out it makes a decent cloak.

Our penultimate stop of the day was not listed in the guidebook but was pretty interesting. We took a look at some of the carbonate layers that had curious features called “tepee structures”. The leading theory for how these structures form is that, when carbonate deposits dry out, new minerals form and cause the layers to expand, causing them to buckle upward. There’s still a lot of debate about how they formed, however. They’re interesting to us martians because in an overhead view, the buckled zones form polygons, and there are polygonal features all over on mars.

A good example of a "tepee structure" is visible in the rocks here, just right of center. Geologists aren't completely sure how they form but the leading theory is that it has something to do with the rocks expanding as they dry out and new crystals form.

Our final stop was also not listed in the guidebook. We decided that since we had been talking about the ancient reef so much that we should take a look at it. Within the carbonates of the reef we found a lots of interesting fossils, including a texture that looked like miniature stromatolites, large spiral shells, and crinoid remains.

That concludes Day 2 of the field trip! Day 3 was a visit to Carlsbad Caverns – stay tuned for lots of pretty pictures!