“A rose by any other name…”

In my last post, “It seems the sky is falling…”, I talked about the Russian meteor event and flyby of asteroid 2012 DA14, both of which occurred on Friday, February 15, 2013. In that post I talked a lot about the various terms of things in space that can enter the Earth’s atmosphere and ultimately cause an “impact”. But there are a lot of terms and some of them have very minute differences, so I figured I’d devote a post just to explaining these terms. Specifically, I’d like to look at a few differences.

“Meteoroid” vs. “Meteor” vs. “Meteorite”

These words all share the same root, the Greek word meteōros, meaning “suspended in the air”, and look very similar, but they do mean different things. To start off, let’s think of a small piece of rock in space. We don’t care what kind of rock it is or where it comes from, let’s just call it a small rock. Now, let’s say that small rock is happily zipping around the solar system, obeying the law of gravity as it orbits the Sun, when suddenly it gets too close to Earth and the gravitational pull of the planet sends tugs it out of its original orbit and towards our planet. Now, that small piece of rock that’s on it’s way into the Earth’s atmosphere, that’s a “meteoroid”. Once that “meteoroid” hits the Earth’s atmosphere travelling at high speed it’s going to heat up and leave a trail in the sky. That heating up and the resulting streak in the sky is a “meteor”- commonly referred as a “shooting star”. If you get a whole bunch of associated “meteoroids”, say a whole bunch of little pieces of rock left over from an asteroid or comet that passed by, that enter the atmosphere at the same time, creating meteors, that’s called a “meteor shower”. So, the “meteoroid” is the small rock that causes streak of light and the “meteor” is the actual visible streak we see. Now as that “meteoroid” is hurtling through the atmosphere and heating up, it can literally blow up. That huge flash that’s caused by the disintegration of the “meteoroid” is known as a “fireball” and really bright “fireballs” are known as “bolides”. That huge flash of light is usually associated with a large deposit of energy into the atmosphere that causes a pressure wave like to ones seen in Tunguska and Chelyabinsk.

A meteor or “shooting star” streaking across the sky is really a piece of debris burning up in the atmosphere. Credit: Wikipedia

The solar system is full of little pieces of debris moving really fast and without the atmosphere that debris would constantly be pummeling the surface of the planet…and us. So the atmosphere protects us. Things are constantly entering the atmosphere and burning up, creating “meteors”. Most of these “meteoroids” are about the size of a pebble- much to small to reach the Earth’s surface. But it does happen occasionally. When large objects enter the atmosphere and make it down to Earth, that remaining piece of rock that reaches the ground is known as a “meteorite”. So yeah, if you’re one your way to work in the morning and see that there’s a huge piece of rock sitting on your car, that’s probably a “meteorite”…or there’s someone who really doesn’t like you. Don’t worry though, as Bad Astronomer Phil Plait writes, only one person has ever been hit by a meteorite and that occurred in Alabama in 1954.

This Canyon Diablo meteorite was part of the 50-meter asteroid that formed the mile-wide Meteor Crater in Arizona. Credit: Wikipedia

Now, not all “meteors” and “meteorites” are caused by natural objects in space. Think about all of the satellites and “space junk” orbiting the Earth. If any of that space junk were to re-enter the atmosphere it would burn up, just like a space rock, and cause a meteor. And another, less appealing example is astronaut waste. On the now-retired Space Shuttles, the urine was expelled out into the upper atmosphere to burn up/evaporate– this actually created a visible glow. Solid waste on the Space Shuttles was collected and removed once the Shuttle returned to the ground, unfortunately that’s not really an option on the International Space Station (ISS), where astronaut waste is stored, then loaded into a disposable space probe and ejected out to burn up in the atmosphere. So yeah, next time you wish on a shooting star, just think that it might actually be astronaut poop.

“Comet” vs. “Asteroid”

Okay so now we’ve talked about the differences between the things that enter the atmosphere. But beyond man-made sources, where do those “meteoroids” come from? Many of them are from rocky, metallic objects in the solar system known as “asteroids”. What are asteroids? According to NASA:

“Most asteroids are made of rock, but some are composed of metal, mostly nickel and iron. They range in size from small boulders to objects that are hundreds of miles in diameter. A small portion of the asteroid population may be burned-out comets whose ices have evaporated away and been blown off into space. Almost all asteroids are part of the Main Asteroid Belt, with orbits in the vast region of space between Mars and Jupiter.”

Most asteroids are actually leftover bits and pieces of planets that weren’t able to coalesce under gravity. As the NASA page describes, most asteroids live in the Asteroid Belt that orbits between Mars and Jupiter. However, as those asteroids travel around the Sun, they can bump into each other, causing a rogue asteroid to leave the Asteroid Belt and traverse the solar system. Sometimes those asteroids fall into the Sun, sometimes they collide with Earth or other planets.

Vesta, one of the largest asteroids in the solar system, was recently studied by NASA’s Dawn mission. Dawn was the first spacecraft ever to go into orbit around an asteroid. Credit: Wikipedia

So what’s the difference between an asteroid and a comet? A “comet” is an icy body that lives out in the farthest regions of the solar system. There is belief by scientists that many comets primarily live in a region at the edge of the solar system known as the Oort Cloud. As these icy bodies come into the inner solar system and approach the Sun, they increase in brightness as the heat from the Sun causes the ice to melt and reflect sunlight. Comets are generally much easier to view than asteroids due to the high reflectivity of the water vapor it releases as they travel through the inner solar system. Generally comets that pass by the orbit of the Earth leave a debris trail in their wake. When the Earth’s orbit takes it through one of those debris trails, it causes a meteor shower.

Comet West made a spectacular show for skywatchers in March 1976. This image shows a great example of the two types of tails that comets often have. One tail is caused by water vapor coming off from sunlight and the other is ionization caused by the solar wind of particles streaming off of the Sun. Credit: APOD/NASA

So comets are mostly icy bodies that live out at the very edge of the solar system and asteroids are rocky, metallic bodies that generally live in the Asteroid Belt in the region between Mars and Jupiter.

So what did we learn?

So let’s review in this handy table made by the great folks at NASA’s Near-Earth Object Program:

Asteroid A relatively small, inactive, rocky body orbiting the Sun.
Comet A relatively small, at times active, object whose ices can vaporize in sunlight forming an atmosphere (coma) of dust and gas and, sometimes, a tail of dust and/or gas.
Meteoroid A small particle from a comet or asteroid orbiting the Sun.
Meteor The light phenomena which results when a meteoroid enters the Earth’s atmosphere and vaporizes; a shooting star.
Meteorite A meteoroid that survives its passage through the Earth’s atmosphere and lands upon the Earth’s surface.

The Cosmic Distance Ladder, part 2…

Let’s continue our explanation of how astronomers are able to gauge the distances to celestial objects. In my first post on this topic, we talked about how radar ranging and stellar parallax are used to determine distances in the solar system. Now we’ll continue working our way up the Cosmic Distance Ladder.

Beyond our solar system

As we leave our local planetary neighborhood, our solar system, we can still use stellar parallax up to a point. In fact, I received an email from Scott in Placentia, CA, asking “What maximum distance an object can be reliably determined by parallax measurement using the latest  technology?” As I explained to Scott in my response, it’s hard to answer that question with a single number. Ideally, stellar parallax should always work, because the stars close to us will always move at least a little bit with respect to the background stars. Unfortunately as we look at stars farther and farther away, the angle that the near-ground star moves gets smaller and smaller. As you can imagine there is going to be a point where that slight angular movement is almost imperceptible. However, technology is always improving. In 1989, the European Space Agency (ESA) launched the Hipparcos mission which was specifically designed for astrometry- determining the position and location of stars. The Hipparcos mission found the positions of nearly 100,000 stars as far away as 1,600 lightyears. Expanding on that mission’s success with new technology, another mission named Gaia is slated to launch this summer and claims to have the ability to find distances to stars tens of thousands of lightyears using stellar parallax. Some sources claim that stellar or trigonometric parallax is limited by current technology to around 1,000 parsecs or roughly 3,260 lightyears.

Examining other Suns

Once we reach that upper limit for the use of stellar parallax, where we can no longer accurately measure the angular shift of the star with reference to the background stars, we have to turn other methods for determining distances. The next technique we need to rely on is called spectroscopic parallax. Now, confusingly this new type of parallax is totally different from and unrelated from actual (stellar) parallax, it just uses the word “parallax” because it’s a technique used to find distances, like parallax. (That’s not confusing at all…) Okay, so how does this spectroscopic parallax work? Well you might remember in The Cosmic Distance Ladder, part 1… I talked about an important instrument used by astronomers called a spectrometer (a.k.a. “spectrograph” or “spectroscope”). These extremely useful devices break white light up into all the colors of the rainbow- this resultant array of colored light is called a spectrum. You’ve probably seen this phenomenon before. Well spectroscopic parallax, as the name implies, is all based on being able to take a good spectrum of a star. This is what sets the upper limit on the maximum distance of objects that we can determine using this technique; with current technology, spectroscopic parallax is limited to roughly 10,000 parsecs (1 parsec = 3.26 lightyears = 19.2 trillion miles). For distances where both spectroscopic and stellar (trigonometric) parallax can work, we generally use stellar parallax because it’s more precise- you’ll see why in a bit.

A prism is an example of a very simple spectrometer. Also known as “spectrographs” or “spectroscopes”, these instruments break down white light into its component colors and are integral to astronomers. Credit: Montana Space Grant Consortium

You might also remember in my recent post about stellar classification, that I explained how each stellar class has a spectrum that is unique to that class.So that means that if you look at a nearby B-type star and a far away B-type star, they should have the spectra that are nearly identical. The difference between the two measured spectra will be their intensity, which correlates to the brightness or luminosity of a star. But now we have to be careful because there are two types of brightness: apparent magnitude and absolute magnitude. Absolute magnitude is how bright an object actually, intrinsically is, while apparent magnitude is how bright it appears to be at Earth if you ignore the atmosphere. So basically absolute magnitude is how bright an object would be if you were at it and apparent magnitude takes into account how far away you might be from the object. Think about a lightbulb: absolute magnitude would be the physical amount of light that the bulb puts out and apparent magnitude is the amount of light you measure from the bulb when you stand on the opposite side of the room. As you can imagine, the bulb will appear less bright the farther away from it you are. Same with stars.

Now, once you’ve measured the apparent magnitude (using some sort of light collecting device) to see how bright the star appears to be, you have to figure out the absolute magnitude. This can be a little tricky and involve some guesswork, but the main tool we use is the Hertzsprung-Russell diagram.

A Hertzsprung-Russell diagram like this makes it easy to determine the absolute magnitude range of each stellar class. Credit: Swinburne University

As you can see, when you plot the H-R diagram, you can easily determine a range of absolute magnitudes that apply to each spectral class. Unfortunately that means there isn’t one right answer, so you can’t get an exact distance for the star…but you can get a pretty good range. Once you determine an appropriate value of absolute magnitude (M), you need to use some math and a mathematical formula known as the distance modulus.

Yay math!

Now that we have the apparent magnitude (m), which we measured, and the absolute magnitude (M), which we inferred from the H-R diagram because we know the star’s spectral type, we can now use both to get the distance modulus: m – M. You might ask, “How does that help?” Well if you think about it, the difference between the absolute brightness and apparent brightness of a star is determined by distance; naturally then there is a mathematical relation that proves that.

Distance Modulus formulaWoah, that probably seems like a lot of math…but it’s not so bad. The lefthand-side of the equation is our distance modulus (m – M), that gives us a dimensionless number (since neither m or M has a unit of measurement like feet or grams) that’s the difference between the absolute and apparent magnitudes. Since the lefthand-side has no units, then that means the righthand-side can’t have them either, that works out as long as we say that the 10 in the denominator is in the unit of parsecs, hence the “pc“. Then our distance (d) will be in units of parsecs and everything is balanced out correctly. So rearranging this equation to solve for the distance, we get:

Distance formulaAnd calculating that gives us the distance to the star, d. Now granted, we might need to do that for a high and low value of M, based on how we read the H-R diagram, meaning we’d get a range of distances and not a single answer, but it still gives us a much better idea than we had about these far away stars. This is why we’d choose trigonometric parallax over spectroscopic parallax for distances where both can work, but for distances beyond the reach of stellar parallax, then spectroscopic parallax is better than nothing! Somewhere “between A and B lightyears away” is much better than “really far”!


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The world will not end today…

Okay, this is really getting pretty infuriating. I have friends, family, and strangers messaging me about when the planets will align tomorrow.

So let’s set the record straight…or at least as much as we can by answering a few simple questions regarding this Mayan end-of-the-world who-hah and why the world will NOT end today.

Where did this idea of the world ending even come from?

The ancient Maya civilization (aka the Mayans), that lived in Central America from roughly 1800 BC until the Spanish wiped the last of them out around 1700 AD were great astronomers. They had their own constellations, pre-telescopic knowledge of the Orion Nebula as a fuzzy object in the sky, and some of their sites are oriented to astronomical objects such as the Pleiades star cluster. Like many advanced cultures, the Mayans used a calendar. They didn’t invent the calendar, but they used it, like most Central American civilizations previous to Columbus coming to the New World; however, they did add on to it.

A view of a Mayan calendar wheel. Credit: www.epicpodquest.com

The Maya came up with a very different calendar from what we use. They have what we call “the Long Count”, which is made up of 13 “baktun”. Each “baktun” is comprised of 20 “katun”. Each “katun” is 20 “tun”, each “tun” is 18 “unial”, and each “unial” is 20 “kin”. What the heck does that mean? Well, we can easily make the metaphor that the Mayan “Long Cycle” is like a year in our very own modern day Gregorian calendar. Now, a “kin” to the Maya is equivalent to a modern day, so a Long Cycle is MUCH longer than a Gregorian year- it’s actually roughly 5,125 years. But here I’m using the analogy just to make a point.

Mayan: 1 Long Cycle = 13 baktun = 260 katun = 5,200 tun = 93,600 unial = 1,872,000 kin

Gregorian: 1 millennium = 10 centuries = 100 decades = 1,000 years = 12,000 months = 365,250 days

When you get a Gregorian calendar for your desk or wall, it usually only has a single year in it, for instance, your current calendar probably doesn’t extend into 2013. Of course that doesn’t mean that 2013 doesn’t exist, you just need a new calendar. Well, the same thing happened with the Maya, they stopped generating calendars beyond this current baktun, which would end in our modern Gregorian time at December 21, 2012 at 11:11 GMT. But like I said, this doesn’t mean the world is going to end. It’s this “reset” of the Mayan calendar that has fueled the plethora of end-of-the-world scenarios.

Looking at this another way, imagine if there WAS a cataclysmic end of the world tomorrow and then far in the future an advanced civilization found what was left our world and realized that there were no calendars that existed beyond 2013…what might they conclude? Oh no, the human calendar must have ended after January 31, 2013!? We all know that’s not true, but one could imagine how an ignorant futuristic civilization might be confused.

Based on this “end of the Mayan calendar”, people across the world and across the internet have tried to come up with ways and reasons that the world might end on December 21, 2012. Some of these catastrophes are minutely based on real things, many are not, and almost all of them are ridiculous. On top of that, the movie 2012 didn’t help the commotion.

What is a planetary alignment and is there going to be one?

A planetary alignment, or conjunction, is when planets appear to lineup in the sky from Earth and they occur fairly frequently. There are a lot of hoaxes related to the alignment of the planets and how that will impact Earth. There’s also another idea that the Earth and Sun will align with the center of the Milky Way galaxy and something cataclysmic will happen to destroy the Earth. This isn’t going to happen. Here’s an article by Francis Reddy of NASA Goddard Space Flight Center that explains why an alignment with the galactic center won’t mean the end of days. So no, don’t try to go outside and look for an alignment of planets in the sky, you won’t see anything.

Now, there was some more baloney going around the internet about a planetary alignment over the pyramids at Giza on December 3, 2012. That was also a hoax… aka NOT REAL!

This photo of a supposed December 3 planetary alignment of the pyramids quickly made the rounds all over the internet. Too bad it’s not real. Credit: Bad Astronomy

Is a rogue planet or asteroid going to crash into the Earth?

NO! Of course not! NASA has a whole division of scientists, in the Near-Earth Object Program, who work to identify and track objects that could pose potential danger to Earth. So far, they have no indication that anything will impact the Earth. There are stories of a rogue world called “Nibiru” that is supposedly going to crash into the Earth. This false claim of a rogue planet-destroyer has been warped and somehow now been misconstrued even further to include an actual dwarf planet, called Eris, that lives out in the Kuiper Belt. This planet was originally referred to as “Planet X”- another claimed possible bringer of Earth’s destruction. So recap: Eris is real, was once called Planet X, Nibiru is not real…and NONE OF THEM WILL IMPACT THE EARTH.

Although it might be a nice excuse to get out of work, don’t expect a killer planet to crash into Earth and obliterate it anytime soon. Credit: www.londonlovesbusiness.com

Is the Earth’s magnetic field or a polar shift going to kill us all?

Again, no. Scientists know from rocks on the floor of the oceans that the Earth’s magnetic field, which protects us from the harmful energetic particles that come streaming off the Sun, actually reverses fields. Now, generally the field of Earth does shift every 400,000 years and we’re sort of overdue for one. However, when the magnetic field does reverse (referred to as a polar shift), it won’t be instant- at least we don’t think so- and it probably won’t happen for a couple more millennia.

So there you have it, no the world will not end. Yes, scientists are pretty sure- here’s an official website from NASA addressing these issues and concerns in case you’re not convinced. And finally, yes, people on the internet are crazy. So I guess all that’s left to say then is happy new Long Cycle everyone!

The Cosmic Distance Ladder, part 1…

For the past few months, I’ve been spending a lot of time in my position as Manager of the UNH Observatory, in helping to prepare for the 2012 New England Fall Astronomy Festival. The event, lovingly known as NEFAF, is a family-friendly astronomy-related event that will be hosted by the UNH Physics Department in partnership with the New Hampshire Astronomical Society. As you can imagine, this is quite an undertaking, but in an incredibly exciting turn of events, we just found out that Dr. Alex Filippenko, noted astronomer from UC-Berkeley and member of the research team that won the 2011 Nobel Prize in Physics, will be giving the keynote talk at NEFAF 2012! In addition to being a highly acclaimed professor, Filippenko is also the co-author of an extremely popular astronomy textbook and a frequent contributor to the documentary series The Universe on The History Channel.

Dr. Alex Filippenko, the newly announced keynote speaker for the 2012 New England Fall Astronomy Festival to be held at the UNH Observatory.

That extremely exciting news has inspired me to do a couple of posts about the expansion of the universe, the area of research that Dr. Filippenko works on. But before we can really get into talking about that, we need to cover a very basic aspect of astronomy, but something that most non-astronomers don’t really know about. I was at a public session at the Observatory this weekend when a guest who had never studied astronomy before asked me what she thought might be an “ignorant” question: she wanted to know how exactly astronomers knew the distances to objects in space. This is by no means an ignorant question, in fact it’s a very fundamental and very involved question that really gets at the very nature of astronomy.

Astronomy by definition is an observational science. Unlike many other scientific disciplines, astronomers can’t really do experiments in a laboratory (although some do). But the stereotypical astronomer can’t throw his subject (a star or galaxy) on a lab bench and dissect it or set up an experiment to test it, so astronomers need to observe and record data. Okay, so we observe light, that tells us what something looks like, where it is, and how bright it is. Big deal, is that really that helpful scientifically. Well, not really. So we have to come up with ways to get more information from observing the light. The main way we do that is by breaking the light up in a spectrometer, an instrument that breaks light down into a spectrum of colors. This breakdown of light can reveal an abundance of new information including what the object is made up of, how hot it is, how fast and in what direction it’s moving, how old it is, and more.

The question of how astronomers calculate the distance to an astronomical object varies depending on how far away the object is. Because most of these techniques only work up to a certain distance, there is actually a progression of different approaches that astronomers use to measure distance to celestial objects. This list of methods of measuring astronomical distances is known as the Cosmic Distance Ladder (or less poetically, the extragalactic distance scale).

A graphical representation of the distance-measuring techniques that make up the Cosmic Distance Ladder. “1 A.U.” is 1 astronomical unit or approximately 93 million miles, the distance from the Earth to the Sun. A “pc” is a parsec, equal to 3.2 lightyears (206,265 A.U.) or about 20 trillion miles. “Mpc” stands for “Megaparsec” or millions of parsecs. Credit: University of Rochester

In our solar system

The first step in our exploration of the universe was to our own celestial neighborhood. The first step was precise measurement of the size scale of the solar system, which started with the determination of the distance between the Earth and the Sun. As I’ve explained before, this measurement was originally calculated via observations of transits of the planet Venus across the disk of the Sun. Early on in the 20th century, observations of asteroids also played an important role in this measurement. But today the distance from the Earth to the Sun, defined as 1 Astronomical Unit or “AU”, is measured with high precision using radar ranging. By bouncing a radar beam off another planet, usually Venus, and measuring the time that beam takes to return to Earth, scientists can very accurately determine the difference in the size of the two planets’ orbits. Using that difference and the ratio of the two orbital sizes, we can very easily calculate the distance the Earth must be from the Sun. We use a similar process even closer to home. During the Apollo missions of the late 1960s-early 1970s, astronauts deployed the lunar laser ranging experiments, arrays of mirrors that allowed scientists to measure the distance to Earth’s only natural satellite with extreme precision using lasers. This radar ranging is how we’ve calculated the distance to most of the objects in our solar system. More recently, we can also use spacecraft in orbit around other planets as a tape measure by measuring the time it takes for a signal to travel from the spacecraft to its controllers on Earth.

Another  way we can get measure the distance to the planets and to nearby stars is a phenomenon known as stellar parallax. This method is less accurate than radar ranging for planets, but is very good for stars in our local stellar neighborhood. Parallax is something you experience almost every day. Hold your thumb up at arm’s length. Close one eye, then open that one and close the other. Notice how your thumb appears to shift with respect to the objects far off in the distance? That’s parallax! Astronomers take measurements of a planet or star a two points in Earth’s orbit (6 months apart) and measure the angular shift of an object with respect to the background stars between those two measurements. Then, because we know the distance the Earth is from the Sun, we can use some basic geometry to calculate the distance to that star or planet in the foreground.

This diagram shows how parallax is used to find the distance to planets in our solar system and nearby stars. Scientists make two observations 6 months apart, measuring the angle that an object (the red dot) makes with regard to the background stars between the two observations. Then using the distance from the Earth to the Sun (1 A.U.) and some simple geometry, the distance to the object (d) can be calculated. Credit: Hyperphysics

It was using parallax, that Italian astronomer Giovanni Domenico Cassini was able to roughly calculate the distance to Mars in 1672. His calculation was a little bit off though, because instead of taking two measurements 6 months apart, he sent his colleague to Cayenne, French Guiana (on the northern coast of South America) to make observations while he stayed in Paris. Then Cassini could make the same parallax calculation using the known distance between the two observation points (~4400 miles) instead of the distance from the Sun to the Earth. This single direct measurement of the distance to Mars, which is now easily calculated and heavily used by missions such as Curiosity, actually allowed for the calculation of the distances to all the planets. Since geometry and Kepler’s Laws governed the basic ratios the Sun-planet distances, you only needed to measure one Earth-planet distance to be able to easily calculate them all. This major contribution and several others in planetary science (including the discovery of four of Saturn’s moons and joint discovery of Jupiter’s Great Red Spot) prompted NASA to name the Saturn-bound spacecraft mission after the him.

Giovanni Domenico Cassini

[To be continued…]


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Curiosity did not kill the cat…

So as I’m sure you’ve all heard, NASA’s Curiosity rover successfully landed on the surface of Mars in the early hours of yesterday morning (east coast time). In an earlier post, I relayed the video by NASA of the harrowing entry that Curiosity needed to go through to reach the Martian surface safely and highlighted that the entire elaborate landing procedure was 100% automated since it takes double the time the landing would take to occur for information to be relayed back to Earth. And all the taxings of a mission so complicated, despite all the finesse and delicacy needed to execute such a bold attempt, and despite all the things that could go wrong, the scientists and engineers at NASA succeeded. Honestly, if you watch the 7 Minutes of Terror video, realize that scientists built and programmed a machine that could do that all automatically, millions of miles away from Earth (352 million to be exact) while moving at thousands of miles per hour and have it work flawlessly, and aren’t awed and impressed, then well you should probably check your pulse.

The Mars Science Laboratory’s mission is to investigate the interior of the Gale Crater for signs of microbial life. Top left: A profile of Curiosity’s landing site, Gale Crater. Top Right: A simulation of Curiosity’s proposed mission. Bottom: A map showing the distribution of NASA’s missions to the Martian surface. Credit: BBC News

In addition to being the largest rover we’ve ever sent to another world, twice as long (about 10 feet)  and five times as heavy as NASA’s twin Mars Exploration RoversSpirit and Opportunity, launched in 2003, Curiosity also has new equipment that allows it to gather samples of rocks and soil, process them, and then distribute them to various scientific instruments it carries for analysis; that internal instrument suite includes a gas chromatograph, a mass spectrometer, and a tunable laser spectrometer with combined capabilities to identify a wide range of organic (carbon-containing) compounds and determine the ratios of different isotopes of key elements. There’s clearly a reason why the mission is called the Mars Science Laboratory.

This illustration from NASA shows the size and instrumentation of Curiosity that will help it to investigate the possibility of microbial life on Mars. (A) Six independent wheels allowing the rover to travel over the rocky Martian surface. (B) Equipped with 17 cameras, Curiosity will identify particular targets and then zap them with a  laser to probe their chemistry. (C) If the signal is significant, Curiosity will swing over instruments on its arm for close-up investigation. (D) Samples drilled from rock, or scooped from the soil, can be delivered to two hi-tech analysis labs inside the rover body. (E) The results are sent to Earth through antennas on the rover deck. Return commands tell the rover where it should drive next. Credit: BBC News

According to NASA, Curiosity carries with it “the most advanced payload of scientific gear ever used on Mars’ surface, a payload more than 10 times as massive as those of earlier Mars rovers.” All that gear will be important as Curiosity investigates its main science objective: whether or not there is evidence of microbial life (past or present) in Martian rocks. Although both Spirit and Opportunity listed the search for life as among their scientific goals, neither rover was really equipped to search for microbial life; the twin early generation rovers were more specifically looking for water or the evidence of past water on the Martian surface and then whether that water could sustain life. Curiosity, on the other hand, is specifically equipped to look for microbial life (or evidence of it) in the rocks and soil of the Red Planet. More than just the roving explorer that its forebears were, Curiosity is for all intents and purposes a laboratory on wheels.

This image of Curiosity descending to the Martian surface with its parachute was taken by the High-Resolution Imaging Science Experiment (HiRISE) camera on the Mars Reconnaissance Orbiter. The rover is descending toward the etched plains just north of the sand dunes that fringe Aeolis Mons. Credit: NASA

And it’s not just the instrumentation that Curiosity is equipped with that make NASA rover 2.0 better than previous generations, but the technology it used to get to the Martian surface is leaps and bounds ahead of how Spirit and Opportunity landed. If you watch this NASA movie that highlights the landing process for the Mars Exploration Rovers (which only had six minutes of terror), you’ll notice that most of the landing procedure seems similar to Curiosity’s. Extremely high-speed entry into the Martian atmosphere, heat shield, parachute, rocket thrusters, etc. Until you get to the last step, when Spirit and Opportunity wer basically dropped onto the Martian surface at nearly 60 mph, surrounded by huge air bags, and allowed to bounce three or four times until they settled. Compared to the fine precision placement of the Curiosity rover earlier this week, the previous rovers’ landings were downright barbaric, like trying to hunt a deer by throwing rocks.

This image, one of the first returned by Curiosity, shows the rover’s shadow on the Martian surface and one of the main targets of its mission, Aeolis Mons, on the distant horizon. Credit: CNN

Rather than violently smashing the $2.6 billion rover into the surface and hoping for the best, this descent involved a sky crane and the world’s largest supersonic parachute, which allowed the spacecraft carrying Curiosity to target the specific landing area that NASA scientists had meticulously chosen. That landing area is roughly 12 km (7.5 miles) from the foot of the Martian peak previously known as Mount Sharp. Aeolis Mons, as it’s now known, is the 18,000-foot (5,500-meter) peak at the center of Gale Crater, previously known as Mount Sharp. The stratified composition of the mountain could give scientists a layer-by-layer look at the history of the planet as Curiosity attempts its two-year mission to determine whether Mars ever had an environment capable of supporting life.

Possibly the biggest piece of the NASA Curiosity puzzle has been the enormous PR campaign that NASA has thrown behind the rover. Not only has the rover and it’s 7 Minute of Terror video been all over the internet, TV news, newspapers, and other media outlets, but NASA has even gone out of its way to get high-level stars in the fold. Last week they released this video (above) of William Shatner, most famously known as Capt. James Tiberius Kirk of Star Trek, narrating a preview of Curiosity’s “Grand Entrance” to Mars. There was also another video featuring narration by Wil Wheaton (Wesley Crusher from Star Trek: The Next Generation).


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Ride, Sally Ride…

Sally Kristen Ride (1951-2012) Credit: NASA

Sally Ride, who sadly passed away on Monday from pancreatic cancer, was an American hero. She was a scientist, an explorer, and a pioneer. Not only did she break into a world (or beyond a world really) dominated by men, but she also secretly lived her life as the only confirmed homosexual astronaut. I don’t want to dwell on Ride’s sexual orientation because I feel like that will only put a label on her, but I do feel like it’s an important fact that underlines the impact that Sally Ride had on American society and the magnitude of the obstacles that she must have faced and overcome to achieve what she did. On June 18, 1983, she flew as part of the crew of the Space Shuttle Challenger and became the first American woman in space. She served as an inspiration and role model for millions of young girls to whom science and space seemed an inaccessible “boys club” and spent most of her post-NASA career encouraging young people, specifically girls, to pursue careers in the sciences. As this CNN article reports, Ride’s influence and legacy can be seen in the huge growth in female involvement and success in the sciences. Since Ride, 44 more American women have flown in space (compared to 299 American men)– that’s about 13% of all American spacefarers.

Sally Ride was born on May 26, 1951 in Los Angeles, California. Her father, Dale, was a political science professor at Santa Monica College and her mother, Carol, worked as a volunteer counselor at a women’s correctional facility. Both of her parents were extremely involved in the Presbyterian Church; in fact Sally’s sister, Karen (known as “Bear”), is a Presbyterian minister. After high school, Sally attended Swarthmore College for three semesters, took physics courses at UCLA, and then entered Stanford University as a junior where she double majored in English and Physics. She continued on at Stanford for her graduate education, earning both her master’s degree and Ph.D. in Physics. In 1978, the same year she received her Doctorate, she was selected out of over 8,000 applicants as an astronaut candidate by NASA.

Sally attended flight school as part of her astronaut training. She enjoyed it so much that it became a regular hobby. Credit: Women@NASA

Sally spent the next year in astronaut training, studying parachute jumping, water survival, weightlessness, radio communications, and navigation. In fact, she enjoyed flight training so much that flying became one of her hobbies. During the second and third flights of the space shuttle Columbia, she worked on the ground as a communications officer, relaying messages from mission control to the shuttle crews. She was part of the team that developed the robot arm used by shuttle crews to deploy and retrieve satellites.

Sally Ride, the first American female astronaut, experiencing zero gravity. Credit: Women@NASA

As part of the first-ever five-person Space Shuttle crew for the June 1983 STS-7 mission that made her the first American woman in space and the youngest American in space (at age 32) , Ride participated as the crew deployed satellites for Canada (ANIK C-2) and Indonesia (PALAPA B-1); operated the Canadian-built robot arm to perform the first deployment and retrieval with the Shuttle Pallet Satellite (SPAS-01); conducted the first formation flying of the shuttle with a free-flying satellite (SPAS-01); carried and operated the first U.S./German cooperative materials science payload (OSTA-2); and operated the Continuous Flow Electrophoresis System (CFES) and the Monodisperse Latex Reactor (MLR) experiments. In fact, during the mission Ride became the first woman to operate the shuttle’s robotic arm.

“The thing that I’ll remember most about the flight is that it was fun. In fact, I’m sure it was the most fun I’ll ever have in my life.” – Sally Ride on her first flight in space

Sally would go on to fly again with the 13th Shuttle mission, STS 41-G, which launched from Kennedy Space Center on October 5, 1984. She was assigned to fly again in 1986 on STS 61-M, but all mission training was halted in January after the Challenger explosion. Sally served on the Presidential Commission investigating the tragedy. After the investigation was completed, she was assigned to NASA headquarters as special assistant to the administrator for long-range and strategic planning. There she wrote an influential report entitled “Leadership and America’s Future in Space,” and became the first director of NASA’s Office of Exploration. She also served on the panel investigation the Columbia disaster in 2003; she’s the only person to have served on both investigative panels.

After she retired from NASA in 1987, Sally joined Stanford University Center for International Security and Arms Control. She later became a professor of physics at the University of California, San Diego and she served as president of SPACE.com from 1999 to 2000. Driven by her belief and commitment to encourage young people, especially girls, to study science, she started the Sally Ride Science, a science outreach company, in 2001. She also wrote five science-related children’s books: To Space and Back; Voyager; The Third Planet; The Mystery of Marsand Exploring Our Solar System.

It goes without saying that Sally Ride was among the most influential American women of the 20th century. Her excitement about space and dedication to encouraging young people to study science has benefitted our country immensely. She will be remembered and missed. From all the countless children, boys and girls alike, who want to go to space, thank you Sally for boldly going where no American woman went before.

7 Minutes of Terror…

Hello all! So I made it successfully back to NASA Goddard from Snowmass Village, Colorado. The conference went well, but as with all scientific conferences, it was quite daunting. However to help me recover, this weekend I visited the Smithsonian National Air and Space Museum’s Steven F. Udvar-Hazy Center to see the recently retired Space Shuttle Discovery. As I’ve chronicled in the past, Discovery is by far the most accomplished of the five Shuttles that have flown (of which only three survive)– an impressive resume that puts it in the upper echelon of American vessels right alongside the USS Enterprise (that’s the Navy aircraft carrier, not the fictional starship…). Seeing Discovery in person was extremely impressive. Being able to see the scorch marks from reentry on the underbelly of the nose and then realizing that each individual tile is labeled was very cool. Up close, the Shuttle looked much more like a patchwork of different components than the sleek space-faring plane that I’m used to seeing in photos. The size also caught me off guard. I’m not sure why, but I’ve always assumed that the Space Shuttle must comparable in size to a commercial airplane that most of us are used to, like a Boeing 747, but it’s not, it’s much smaller. I guess in a way it was both bigger and smaller than I expected…if that makes any sense. Below are some pictures of Discovery.

Moving on to other cool space things. Have you ever wondered what it would be like travelling to Mars? Well a new short video from the great folks at NASA Jet Propulsion Laboratory (JPL) out in Pasadena, CA shows how harrowing the journey might actually be. The team working on the new Mars rover, Curiosity (part of the Mars Science Laboratory mission) have released a new video, entitled 7 Minutes of Terror, detailing the rover’s planned 7-minute descent through the Martian atmosphere and onto the surface of the Red Planet. If you’ve ever doubted the ingenuity or ability of NASA scientists and engineers then you should definitely watch this short video (it’s much less than seven minutes long). The sheer magnitude of the problem that they are attempting to tackle is impressive enough (aka landing something the size of a couch on an object millions of miles away), let alone the fact that they are doing it without any communication with the spacecraft (the entire landing process will have been completed in the time it takes communication to reach Earth from Mars) and dealing with insanely sensitive and delicate instrumentation. It’s just a great look at how insanely talented and inspiring the folks at NASA are. Kudos to them.

Curiosity will be the third functioning NASA rover on Mars, joining its Mars Exploration Rover brethren Spirit and Opportunity who landed in 2004 (Opportunity is still functioning), and will specifically be investigating the habitability of Mars. Curiosity was specifically designed to study layers in Martian mountains that hold evidence about wet environments of the planet’s early existence and assess whether Mars ever had an environment able to support microbial life forms. The rover, launched on November 26, 2011, is scheduled to land on the Martian surface, near the base of a mountain inside Gale Crater, close to the Martian equator, early on August 6, 2012 (EDT) to begin its two-year prime mission.

NASA’s next Mars rover, Curiosity, on a test drive. Credit: NASA/JPL


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