Each in a class of their own…

Ever wonder what makes stars different from one another? Lots of factors can come into play: size, composition, temperature, and age to name a few. Thankfully many stars are similar and can be grouped together by similarities. So here let’s talk about the history and science of stellar classification.

Shedding some light on spectra

In the middle of the 19th century, a German physicist by the name of Gustav Kirchhoff was doing a lot of research into the field of spectroscopy; collaborating closely with Robert Bunsen, inventor of the best piece of scientific equipment high schoolers are allowed to use. Kirchhoff in his research, came to the conclusion that spectroscopy was governed by three basic laws. These are known today as “Kirchhoff’s laws of spectroscopy” (not to be confused his circuit lawslaw of thermochemistry, or law of thermal radiation– basically this guy made more laws than Congress). Kirchhoff’s laws of spectroscopy dictate that:

  1. A solid (or liquid or gas under high pressure) will give off a continuous spectrum.
  2. A gas under low pressure (i.e. most gases we know of) will produce bright, discrete lines known as an emission spectrum.
  3. If you look at a source of a continuous spectrum from behind a source of an emission spectrum, you will see what looks like a continuous spectrum with black lines missing from it; think of if you took the emission spectrum and subtracted it from the continuous spectrum. This is called an absorption spectrum.

An example of Kirchhoff’s laws of spectroscopy. On the left you see an example of a continuous spectrum (Law 1) and an emission spectrum (Law 2) on the right. In the middle is an example of an absorption spectrum (Law 3), basically the removal of the emission line from the continuous spectrum. Credit: Penn State

Kirchhoff asserted that the wavelength or location of these emission or absorption lines was determined by what atoms or molecules were present in the source. This is true because each element or molecule has a unique atomic spectrum or signature. At the time that Kirchhoff came up with these laws scientists had yet to crack the secret of the internal structure of the atom. Meaning Kirchhoff made these laws based on purely on experimentation. It took another half a century for Niels Bohr to come up with a correct model of the atom that concluded the existence of discrete energy levels that successfully explained Kirchhoff’s emission and absorption lines (and later led to the formulation of quantum mechanics).

Enter the Harem

So back towards the end of the 19th century, a man by the name of Edward Pickering was the director of the Harvard College Observatory. Mr. Pickering decided to take it amongst himself to obtain spectra of as many stars as he could and then index and classify them. So Pickering did what any good scientist would do, he began to collect data. But as you well know, there are a lot of stars in the sky, so before he knew it he was inundated with tons of photographic plates (if you thought film was bad, its predecessor was worse- these plates were usually large heavy pieces of glass mixed with silver salts) containing stellar spectra. Legend has it that Pickering was getting so aggravated by the incompetence of his male research assistants that he exclaimed that his maid could do a better job. So he hired her. Her name was Williamina Fleming and along with Pickering she helped to publish the Draper Catalogue of Stellar Spectra (named in honor of Henry Draper, the first man to take the spectrum of a star on a photographic plate), which had classifications for 10,351 different stars. Once Fleming left Pickering’s service, he hired several other women assistants. Out of this group of women, which became known officially as the “Harvard Computers”, but commonly as “Pickering’s Harem”, came some of the greatest early female astronomers, including Annie Jump CannonHenrietta Swan Leavitt, and Antonia Maury. The initial version of this catalog, published from 1918 to 1924 in 9 volumes, included the positions, magnitudes, and spectral classifications of over 225,000 stars.

Edward Pickering and his “harem” outside a Harvard building in 1913. Annie Jump Cannon stands two to the right of Pickering. Credit: UC- Berkeley

Differentiating the spectral classes

Alright, so how does that help astronomers? Well, in essence a star is a gas under high pressure, meaning it should give off a continuous spectrum according to Kirchhoff’s first law. But the outer layers of a star’s “atmosphere”, called the corona, is a gas under low pressure- meaning we actually see an absorption spectrum (Law 3). (In fact, it was the unexpected discovery of this absorption spectrum that helped us to realize that our Sun had an “atmosphere” or outer layer of hot gas surrounding it.) Since stars of the same size and mass are made up of pretty much the same stuff, they have similar spectra. In fact, this is how astronomers classify stars, by their spectral class. The different stellar spectral classes are O, B, A, F, G, K, and M. Type O stars are the hottest and Type M stars are the coolest. Each spectral class or spectral type has a unique spectrum.

Recreated stellar spectra of each spectral type (from top to bottom): O, B, A, F, G, K, M. Credit: ESA

With a name like that…

Now, like a lot of things in astronomy, this naming scheme is totally absurd and illogical. I wish I had a better explanation for why we have this naming scheme, but basically it’s a historical holdout from back when astronomers started classifying stars without really understanding them. Remember the Harem? Well in the first publication of the catalog in 1890, Williamina Fleming did most of the classification. She used a classification system that had been developed a few decades earlier by the Italian astronomer Angelo Secchi. Since she had so many stars, she took Secchi’s five classes and stretched them out to encompass fourteen classes from A to N. Then she added three more categories (O, P, Q) to encompass stars that would not have fit Secchi’s scheme. A through Q made sense. But then in 1897, Antonia Maury was working on a different set of stars and decided to reclassify what Fleming had done. So she scrapped the letters and made 22 classes from I to XXII…still made sense. Unfortunately, in her rearranging of Fleming’s classes, she wasn’t paying attention to the letters and moved some around, hence O and B moving towards the front.

Finally in 1901, Annie Jump Cannon (probably the most famous and accomplished of the Harem) was cataloging and decided to go back to the letter system and dropped all the letters except O, B, A, F, G, K, and M in that order. Why? I have no idea. For some reason after Ms. Jump Cannon came up with her system they had had enough reclassification and no one suggested, “Hey maybe we should have these make some kind of logical sense.” Astronomers can be infuriating sometimes.  The final crazy product is known today as the Harvard Spectral Classification. So, if you need a way to try to remember Ms. Jump Cannon’s crazy archaic classes, try “OBA Fine Gal (or Guy), Kiss Me!” Of course, the cockamamie lettering system wasn’t enough, Ms. Jump Cannon then needed to add ten subclasses from 0 to 9 for each letter. Meaning not only is a B-type star hotter than a K-type star, but a B1 star is hotter than a B5. Our star, the Sun, is a G2, meaning it’s pretty much right in the middle of the stellar pack.

Digging even deeper

But somehow the crazy letter and number combination still wasn’t quite exact enough. In 1943, three astronomers from the Yerkes Observatory in Wisconsin came up with another classification system that focused not only on the surface temperature of a star (which the Harvard Classification does), but also on the luminosity (or brightness). Basically, you can have a really big red giant star and a teeny tiny white dwarf star that are the same temperature and therefore have similar emission lines. However, you can look at how sharp those emission lines are and determine the surface gravity or pressure that that star must have. When introducing this new factor into the equation, the Yerkes astronomers came up with seven (I-VII) new classes that basically help to dictate what stage of life a star is in.

To try to help this make some visual sense, astronomers have developed a graph called the Hertzsprung-Russell diagram that correlates how bright a star is, how hot it is, and what spectral class it’s in. This pretty ingenious and very common graph helps to simplify a vast amount of knowledge. It’s really pretty obvious how the groups appear when looking at a filled out H-R diagram. Most stars, like our Sun (which is a G2V), are in class V, meaning they are still on the “Main Sequence” and are still fusing hydrogen into helium. As stars live and evolve, they move off of the main sequence and into other branches of the H-R diagram. Can you pick out where the Sun would be on this H-R diagram below?

A Hertzsprung-Russell diagram showing the major classes of stars. The temperature (and spectral classes) run from hottest to coldest, left to right. Generally size decreases from top to bottom. The “Main Sequence” is the diagonal line running through the middle, with the other evolutionary branches around it. Credit: Wikipedia

Advertisements

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…]

————————————————————

Related Posts:

Famous Scientist Profile: Nikola Tesla…

Think about your favorite scientist. Okay, so realistically you probably don’t have an actual “favorite” scientist, but most of you probably thought Einstein, right? Not surprising. Albert Einstein is without a doubt the most notable and famous scientist of the last century, having reached a celebrity status that no scientist before him and very few after have even come close to. Now some of you more hip, savvy science-minded cats out there may have said Carl Sagan or Neil deGrasse Tyson or Richard Feynman or others, but those guys are more famous for being science popularizers than scientists (well Sagan and deGrasse Tyson at least), and I’d say any of those three is perhaps in the parking lot of the same ballpark as Einstein. Einstein’s kind of a big deal, people know him. You have to be pretty “nerdy” to know Feynman. In any case, some might say that Einstein was simply a character that was created by the popular media of the day (photography, radio, magazines, early TV, etc.) which allowed a greater spread of information (the same way TV and the internet have helped Sagan and deGrasse Tyson), but the bottom line is that Einstein basically became the personification of genius. His name become synonymous with superior intelligence. Now that my friends, that’s notoriety.

Nikola Tesla: that mustache can’t hide the genius!

In any case, I guarantee that none of you answered the question of who your favorite scientist is with the man pictured above. That’s Nikola Tesla. And that’s really a shame because he probably had a more significant impact on the development of the modern era than any single person in history. And when you hear “Tesla”, you probably think of loud coil things that shoot out awesome sparks or fancy electric cars. But I’m sure you probably know very little about the actual genius and significance of the man that basically gave birth to modern electricity.

Nikola Tesla was born on July 10, 1856 in Smiljan, a small mountain village in what is now Croatia, but what was then just part of the Austrian Empire. Nikola was born to Milutin Tesla, a Serbian Orthodox priest, and his wife Đuka, who interestingly enough never even learned to read. Nikola was the fourth of five children and the only surviving son (his older brother was killed while riding a horse when Nikola was 5). From very early on, it was clear that Nikola was special. While in school he could supposedly do integral calculus in his head, a feat so astounding that his instructors were convinced that he was cheating. (Note: I don’t know if you’ve ever done integral calculus, but it’s pretty difficult to do with a textbook and a calculator, let a lone doing in your head.) It also didn’t hurt that he supposedly had a photographic memory.

In any case, he attended to the Austrian Polytechnic in Graz, Austria and studied to be an engineer. He never even finished his degree, but was genius enough that he had no problem finding engineering work without it. He ultimately moved to Budapest in 1880 and began working for the Hungarian National Telephone company.

Now around the same time, the guy who we all think of as the father of electricity, you know Thomas Edison (pictured below) was working like a madman in his Menlo Park, NJ laboratory, trying to supply the world with all of his new electrical inventions. By the way, Thomas Edison DID NOT invent the light bulb, in fact, in their book Edison’s electric light: biography of an invention, authors Robert Friedel and Paul Israel compiled a list of 22 inventors who came up with incandescent lamps before Edison. Edison’s light bulb was just way better. And he was able to produce and sell it. It’s similar to Galileo and the telescope: it wasn’t his invention, but he popularized its use for astronomy and history favors the victors, as they say.

Thomas Edison: American inventor & villain

Anyway, Edison was working like a crazy electrical fool in New Jersey, trying to supply the United States and Europe with his amazing new electrical inventions. In 1882, Tesla got a job in Paris working for the Continental Edison Company, basically improving Edison’s designs as they got shipped over to Europe from the States. In 1884, Tesla moved to the U.S. and got a job working for Edison. This must have been similar to Heisenberg working under Bohr in the 1930’s. Edison knew he had a prized asset in Tesla, and he exploited the bejeezus out of him. A perfect example:  In 1885, Tesla told Edison that he could vastly redesign and improve the horribly inefficient Edison motors and generators and Edison offered Tesla $50,000 if he could actually follow through with it. After a few months of work, Tesla succeeded and when he went to Edison to ask for the reward, Edison shrugged him off and said that he was only kidding. Edison did offer him a raise though, an extra $10 on top of his $18 a week salary. Tesla promptly refused and quit.

After that Tesla bounced around from electric company to electric company and for stints had to work as a ditch-digger to make ends meet. He partnered up with George Westinghouse and for awhile worked at Westinghouse Electric & Manufacturing Company. In fact, it was while partnering with Westinghouse that Tesla helped to supply electricity to the 1893 World’s Columbian Exposition in Chicago. The success of that feat was huge because the pair were able to successfully demonstrate the safety and reliability of alternating current (AC) to Americans who were being lied to about it by Edison. Oh right, so here’s where you find out about the other side of Thomas Edison, the side the history books and encyclopedia articles don’t tell you. Edison was totally the villain in this story. In the “War of Currents”, Edison became a fierce rival of Tesla and Westinghouse because he was trying to sell/promote the direct current (DC) system of supplying electricity, as opposed to the alternating current system that Tesla came up with. You can click here to get a quick explanation of the differences in AC and DC currents, but it basically boiled down to the fact that AC was more efficient because it operates with a lower current, so there is little power and energy dissipation, even over exceptionally long distances. Anyways, Edison, with his crazy fame, power, and influence over the American people, began a huge smear campaign against Tesla and alternating current, even going so far as to electrocute puppies as a “demonstration” of how dangerous AC power could be. Even though Tesla’s AC system was more efficient (and is now what we all use in our homes today), Edison’s smear campaign took its toll and is probably one of the biggest reasons why Americans have very little idea who Tesla even is, let alone the impact he had on the world.

Nikola Tesla would often run alternating current (AC) through his own body to demonstrate to the public that it was not as unsafe as Thomas Edison claimed.

In addition to the invention of alternating current (which in itself was amazing), Tesla is also recorded having come up with the idea of the radio before Guglielmo Marconi and radar before Robert A. Watson-Watt. He also supposedly discovered X-rays before Wilhelm Röntgen, theorized the electron before J.J. Thomson found it, built the first hydroelectric plant at Niagara Falls, experimented with cryogenic engineering way before anyone else, was the first person to record radio waves from outer space, discovered the resonant frequency of earth a half-century before anyone else, etcetera, etcetera, etcetera…the list of amazing accomplishments goes on and on. Basically what it boils down to is that Nikola Tesla was AMAZINGLY BRILLIANT and super ahead of his time AND BARELY ANYONE EVEN KNOWS ABOUT HIM!! Oh and I almost forgot, he also died alone in a NYC hotel room, in love with a pigeon. I mean if that story doesn’t scream Academy-Award-winning caliber movie, I really don’t know what else does. I can see Robert Downey, Jr. playing an amazing Tesla.

Which is why I proudly celebrate Nikola Tesla Day every July 10 (you can still celebrate it belatedly), in memory of this truly awesome man. Oh and if you want a really amazing little recap of why Nikola Tesla is so awesome, I point you to possibly my favorite comic from The Oatmeal, entitled “Why Nikola Tesla was the greatest geek who ever lived.” or the Tesla post on bad***oftheweek.com, with the disclaimer that both have some adult language.

<I apologize that these links here at the end have adult language, but I can’t censor them. And apparently people just get very emotional when talking about Nikola Tesla. In any case, I definitely feel that their benefits outweigh the negative of them including bad language.>

————————————————————

Related Posts:

A glimpse of the transit…

Here’s a screen capture from the live NASA webcast of  visible (white) light image of the surface of the Sun. That black spot at about 3 o’clock is Venus. The other small black features are sunspots on the surface of the Sun. Some sunspots can be larger than the Earth. Credit: NASA

Hey everybody! So I hope all of you are watching the NASA live feed of the transit of Venus and seeing cool things like above.

So here is a mid-transit update of some very cool transit things.

First off, you should check out helioviewer.org a very cool website that allows you to make your own compilation of solar images or videos from a multitude of satellites and data from NASA, NOAA, ESA, and more!

Here’s another great shot in the extreme ultraviolet (EUV) from NASA’s Solar Dynamics Observatory (SDO). Again you can see the dark spot, Venus, about halfway across the Sun’s disk. You’ll notice that the EUV allows you to see a lot different detail than the visible light image above. Here we can see the solar corona, or atmosphere, as well as flux tubes (hot plasma trapped along magnetic field lines). That extremely bright region just below Venus with the massive flux tubes flowing out of it is associated with the sunspot you see in the same location on the visible light image above. Sunspots are caused by magnetic field lines on the surface of the Sun that cause a drop in surface temperature (from ~6000 K to only ~3000 K). That temperature drop causes the cooler region to seem dark compared to the rest of the Sun’s surface– hence, sunspots.

An extreme ultraviolet (EUV) image from NASA’s Solar Dynamics Observatory (SDO) of Venus transitting the Sun’s disk. Credit: NASA

And just in case that’s not enough, here’s a link to a movie of Venus’s progression during the transit from SDO, care of @Camilla_SDO.

————————————————————

Related Posts:

Today is transit day…

Hello friends, don’t forget that this evening starting around 6pm EST you’ll be able to see Venus transiting the disk of the Sun, a phenomenon that won’t occur again until 2117!!

Remember, DO NOT LOOK AT THE SUN DIRECTLY WITHOUT PROPER PROTECTION! For safe tips on how to view the transit, click here. Or to be super safe (and mobile) you can check out NASA’s live webcast of the transit from the Keck Observatories at Mauna Kea, Hawaii. That broadcast will feature UNH alumnus and thesuntoday.org creator Dr. C. Alex Young of NASA Goddard Space Flight Center.

For more information about the transit, you can visit NASA’s official transit webpage, thesuntoday.org, or transitofvenus.org.

Also, to help you get super pumped about the transit, here are some fun tidbits.

Here’s a link to my friend and fellow grad student, Mark Zastrow from Boston University’s Department of Astronomy, detailing the amazing and harrowing tale of 18th century French astronomer Guillaume Le Gentil‘s trek to observe the pair of Venus transits in the 1760s: The Worst Observing Run Ever

And to prove that Venus is actually going to cross the disk of the Sun, here’s a video from NASA’s SOlar and Heliospheric Observatory (SOHO) satellite. The video is of a series of coronagraph images. Coronagraphs image the corona, or atmosphere of the Sun, and associated flares and coronal mass ejections by blocking out the extremely bright disk of the sun. You’ll notice the big empty blue spot in the middle of the picture, that’s the blocked out part and that white ring indicates the actual outline of the Sun’s circumference. The Sun’s really bright, so you need to block out a lot more than just the disk. You’ll see some big blobs of particles and plasma coming off the Sun, that’s normal solar activity. And finally you’ll see that bright image approaching the Sun from the left, that’s Venus, reflecting the incredibly bright light from the Sun.

Hope you like all that. Enjoy the transit! And if you have any cool transit-viewing pics or experiences, feel free to share them in the comments!

————————————————————

Related Posts:

SpaceX: mission (and history) accomplished…

Here’s SpaceX’s Dragon capsule after it was captured by the International Space Station‘s (ISS) Canadarm2 early this morning. Credit: www.2space.net

It’s official! According to NASA’s official press release, “The International Space Station Expedition 31 crew successfully captured the SpaceX Dragon capsule with the station’s robotic arm at 9:56 AM EDT. The feat came 3 days, 6 hours, 11 minutes and 23 seconds after the mission’s launch. The station was 251 miles over northwest Australia when capture occurred.” This was soon followed by, ” The SpaceX Dragon capsule was securely bolted to the Harmony module of the International Space Station at 12:02 p.m. EDT.” As I’ve mentioned in previous posts, SpaceX has made history and single-handedly ushered in a new era of space exploration. They are now the only private company ever to launch into orbit and return and the only to dock with the International Space Station (ISS). Not too shabby for an endeavor that only started a mere four years ago after President Obama announced the beginning of NASA’s new Commercial Crew Program (CCP). The success of Dragon‘s launch, rendezvous, capture, and docking with the ISS can’t be emphasized enough, this now helps to close the space gap which I have mentioned previously and no longer leaves the U.S. without a viable means to launch astronauts into space. Of course, there will still need to be more test flights and it might still be awhile before NASA okays manned flights of its astronauts on Dragon capsules, but this is definite and exciting progress to say the least!

I think without a doubt though, my favorite tidbit from this whole event was the reaction by NASA astronaut and current ISS resident, Don Pettit who relayed this gem after the ISS’s Canadarm2 (the robotic arm used to grab and move things outside the station) had successfully grabbed hold of the Dragon capsule: “Houston, it looks like we got us a Dragon by the tail.” Classic.

At 12:02pm EST, Dragon successfully berthed (docked) with the ISS’s Harmony module. Credit: NASA

————————————————————

Related Posts:

%d bloggers like this: