With the upcoming transit of Venus, scientists from across the world are coordinating with groups to measure the contact times of the transit and re-measure the distance to the Sun. There are several websites (such as this one, or this one) that detail how to do this, and a nice (math heavy) paper by Mignard in 2004 (PDF file here). Many of these methods, however, require you to get the full duration of the transit or directly measure the parallax with imaging. Here I describe a much more simple method that requires you to measure only the time at ingress interior or egress interior for two locations on the Earth. This method is convenient as you don't need to witness the full transit (only ingress seen from Easter Island, for example). This is a retelling of the information derived by Udo Backhaus in this website with some added explanations.
Sunday, May 20, 2012
Tuesday, May 15, 2012
Book Review: House of Chains by Steven Erikson
I understand that Ian Cameron Esslemont has also written books in the Malazan universe and they both collaborated on the series. I may have to check Esslemont's works later on, but I intend to finish the 10-book series first.
Wednesday, May 9, 2012
A Memory of Light Cover for Kindle
This may be old news for some, but Tor has revealed the cover for the final book of the Wheel of Time, A Memory of Light by Robert Jordan and Brandon Sanderson:
In my opinion, this is one of the best covers to date for the series. It's done by a different artist, Michael Whelan, who is well known in the community and has created many fabulous book covers (for example, see The Stormlight Archives #1: The Way of Kings by Brandon Sanderson). All the prior Wheel of Time covers were done by Darrell Sweet, but sadly he passed away in December before finishing his sketch for the cover:
If you own a Kindle or other e-reader, you may want to use the new Whelan cover as your background/wallpaper/screensaver, so you can pretend you're reading the final book of the series well ahead of everyone! I searched, but couldn't find that anyone had converted the cover (a trivial process), so here you go:
You can download the 600x800 version here (from the Picasa album).
Instructions for how to set it up on your device will vary, but here is some useful information one for the Kindle.
If you prefer Sweet's version (with the title/authors added by Aidan Moher) here you go:
You can download the 600x800 version here. It looks a bit grainier since the original size was smaller than this. I personally prefer the Whelan cover.
In my opinion, this is one of the best covers to date for the series. It's done by a different artist, Michael Whelan, who is well known in the community and has created many fabulous book covers (for example, see The Stormlight Archives #1: The Way of Kings by Brandon Sanderson). All the prior Wheel of Time covers were done by Darrell Sweet, but sadly he passed away in December before finishing his sketch for the cover:
If you own a Kindle or other e-reader, you may want to use the new Whelan cover as your background/wallpaper/screensaver, so you can pretend you're reading the final book of the series well ahead of everyone! I searched, but couldn't find that anyone had converted the cover (a trivial process), so here you go:
You can download the 600x800 version here (from the Picasa album).
Instructions for how to set it up on your device will vary, but here is some useful information one for the Kindle.
If you prefer Sweet's version (with the title/authors added by Aidan Moher) here you go:
You can download the 600x800 version here. It looks a bit grainier since the original size was smaller than this. I personally prefer the Whelan cover.
Tuesday, May 8, 2012
Astronomy: Spitzer Sees Light from Super Earth
The Spitzer Space Telescope is an orbiting satellite that takes data at near and mid infrared wavelengths. It had to be cryogenically cooled, otherwise it would detect its own heat in its instruments! Right now, the cryogen has run out so it only operates at the shortest wavelengths (3.5 and 4.6 microns), but is still useful for a lot of science ranging from brown dwarfs to exoplanets to dusty galaxies.
Today, NASA has revealed that Spitzer has detected the light from a distant super-Earth; the first ever such observed. At first I was surprised, since I had heard about Spitzer imaging a planet before (HD 209458b and TrES-1, see here), but it turns out that these were gas giant planets, not a super Earth.
Today, NASA has revealed that Spitzer has detected the light from a distant super-Earth; the first ever such observed. At first I was surprised, since I had heard about Spitzer imaging a planet before (HD 209458b and TrES-1, see here), but it turns out that these were gas giant planets, not a super Earth.
Tuesday, May 1, 2012
Exciting May Book Releases
This month sees the release of several books I'm very excited for. So much so that I almost (but not quite) regret starting House of Chains, fourth book of the Malazan Book of the Fallen rather than waiting to read these titles.
May 1
The Drowned Cities by Paolo Bacigalupi
This young adult novel is set in the same post-apocalyptic universe of Ship Breaker, which I recently finished reading. Despite being categorized as "young adult," I'm sure this book, like Ship Breaker before it, is far more complex than meets the eye and engaging for audiences of all ages. io9 has a magnificent book trailer here, just watching it makes me want to go buy the book and start reading it now.
May 1
The Killing Moon by N.K. Jemisin
This is the first book in the Dreamblood duology (so, two books). The next book comes out in June, so you don't have to wait years and years for the conclusion. Jemisin has proven herself as a great author with The Inheritance Trilogy (check out my review of book 3, The Kingdom of Gods). The setting and magic for this duology is said to have come from Jemisin's fascination in ancient Egypt, Freudian dream theory, and Jung's ideas about the collective unconscious. Sounds very interesting and I'll be sure to check it out.
May 15
Railsea by China Mieville
On board the moletrain Medes, Sham Yes ap Soorap watches in awe as he witnesses his first moldywarpe hunt: the giant mole bursting from the earth, the harpoonists targeting their prey, the battle resulting in one’s death and the other’s glory. But no matter how spectacular it is, Sham can't shake the sense that there is more to life than traveling the endless rails of the railsea–even if his captain can think only of the hunt for the ivory-coloured mole she’s been chasing since it took her arm all those years ago. When they come across a wrecked train, at first it's a welcome distraction. But what Sham finds in the derelict—a series of pictures hinting at something, somewhere, that should be impossible—leads to considerably more than he'd bargained for. Soon he's hunted on all sides, by pirates, trainsfolk, monsters and salvage-scrabblers. And it might not be just Sham's life that's about to change. It could be the whole of the railsea.
Mieville is a great story teller and a master of language. You can see he's drawn from Melville's Moby-Dick for this novel. I have no doubt that this book will be an amazing ride into yet another fantastical world. Unlike Bacigalupi and Jemisin, Mieville has less of an online presence (ie, twitter, blog, etc), but he doesn't need it: his works are of such quality that people all over keep talking about it. You've probably heard of the numerous awards that his last book, Embassytown, has been nominated for (this just in: Embassytown among the 2012 Locus Award finalists).
All these books have free previews available online, either through ebook stores like Amazon, or through the author's own websites. I personally have not read any of the previews: I trust these authors enough to buy their works without any prior glimpses.
Right now I'm about a third of the way through my current book and will probably start The Killing Moon next. Though I have a few other sci-fi novels queued up, it looks like those will have to wait. Why does my to-read list increase faster than I can read?
Did I miss any notable May releases? I'm sure there are plenty of books being released every month, but in the realm of sci-fi and fantasy, these are the ones I personally am looking forward to reading.
Update (May 2):
It looks like I did forget one exciting release!
May 1
Soldier boys emerged from the darkness. Guns gleamed dully. Bullet bandoliers and scars draped their bare chests. Ugly brands scored their faces. She knew why these soldier boys had come. She knew what they sought, and she knew, too, that if they found it, her best friend would surely die.
In a dark future America where violence, terror, and grief touch everyone, young refugees Mahlia and Mouse have managed to leave behind the war-torn lands of the Drowned Cities by escaping into the jungle outskirts. But when they discover a wounded half-man--a bioengineered war beast named Tool--who is being hunted by a vengeful band of soldiers, their fragile existence quickly collapses. One is taken prisoner by merciless soldier boys, and the other is faced with an impossible decision: Risk everything to save a friend, or flee to a place where freedom might finally be possible.
This young adult novel is set in the same post-apocalyptic universe of Ship Breaker, which I recently finished reading. Despite being categorized as "young adult," I'm sure this book, like Ship Breaker before it, is far more complex than meets the eye and engaging for audiences of all ages. io9 has a magnificent book trailer here, just watching it makes me want to go buy the book and start reading it now.
May 1
In the desert city-state of Gujaareh, peace is the only law. Along its ancient stone streets, there is no crime or violence. Priests of the dream-goddess, known as Gatherers, maintain order: harvesting the dreams of the citizens, healing the injured, and guiding the dreamers into the afterlife. . .
When Ehiru-the most famous of the city's Gatherers-is sent to harvest the dreams of a diplomatic envoy, he finds himself drawn into a conspiracy that threatens to drag the dreaming city into war.
This is the first book in the Dreamblood duology (so, two books). The next book comes out in June, so you don't have to wait years and years for the conclusion. Jemisin has proven herself as a great author with The Inheritance Trilogy (check out my review of book 3, The Kingdom of Gods). The setting and magic for this duology is said to have come from Jemisin's fascination in ancient Egypt, Freudian dream theory, and Jung's ideas about the collective unconscious. Sounds very interesting and I'll be sure to check it out.
May 15
On board the moletrain Medes, Sham Yes ap Soorap watches in awe as he witnesses his first moldywarpe hunt: the giant mole bursting from the earth, the harpoonists targeting their prey, the battle resulting in one’s death and the other’s glory. But no matter how spectacular it is, Sham can't shake the sense that there is more to life than traveling the endless rails of the railsea–even if his captain can think only of the hunt for the ivory-coloured mole she’s been chasing since it took her arm all those years ago. When they come across a wrecked train, at first it's a welcome distraction. But what Sham finds in the derelict—a series of pictures hinting at something, somewhere, that should be impossible—leads to considerably more than he'd bargained for. Soon he's hunted on all sides, by pirates, trainsfolk, monsters and salvage-scrabblers. And it might not be just Sham's life that's about to change. It could be the whole of the railsea.
Mieville is a great story teller and a master of language. You can see he's drawn from Melville's Moby-Dick for this novel. I have no doubt that this book will be an amazing ride into yet another fantastical world. Unlike Bacigalupi and Jemisin, Mieville has less of an online presence (ie, twitter, blog, etc), but he doesn't need it: his works are of such quality that people all over keep talking about it. You've probably heard of the numerous awards that his last book, Embassytown, has been nominated for (this just in: Embassytown among the 2012 Locus Award finalists).
All these books have free previews available online, either through ebook stores like Amazon, or through the author's own websites. I personally have not read any of the previews: I trust these authors enough to buy their works without any prior glimpses.
Right now I'm about a third of the way through my current book and will probably start The Killing Moon next. Though I have a few other sci-fi novels queued up, it looks like those will have to wait. Why does my to-read list increase faster than I can read?
Did I miss any notable May releases? I'm sure there are plenty of books being released every month, but in the realm of sci-fi and fantasy, these are the ones I personally am looking forward to reading.
Update (May 2):
It looks like I did forget one exciting release!
May 4
The King's Blood by Daniel Abraham
WAR AND MADNESS CAST SHADOWS
OVER THE LANDS DRAGONS ONCE RULED.
Geder Palliako's star is rising. He is a hero of Antea, protector to the crown prince, and darling of the court. But storms from his past are gathering, and with them, a war that will change everything.
Cithrin bel Sarcour founded a powerful bank on stolen wealth, forged papers, and ready blades. Now every move she makes is observed, recorded, and controlled. Unless Cithrin can free herself from her gilded cage, the life she made will be for naught; war may provide just the opportunity she needs.
An apostate priest sees the hidden hand behind all: a long-buried secret of the dragon empire threatens everything humanity has built. An age of madness and death is on the way, with only a few doomed heroes to stand in its way.
This is the second book in The Dagger and The Coin series. I read the first book of that series (The Dragon's Path) and considered it to be one of my top 5 books I read in 2011. This is traditional epic fantasy, but with some cool elements in it. The author claims he borrowed ideas from multiple sources and yet he managed to meld everything together so it feels new and fresh. I like it! I'm looking forward to this book and I can't believe that it slipped under my radar.
Saturday, April 28, 2012
Transit of Venus: June 2012
On June 5/6, 2012 we will witness one of the rarest, yet predictable, astronomical phenomena: the transit of Venus.
What is a transit?
Just like the Moon will sometimes pass between the Earth and the Sun (causing a solar eclipse), so too do the planets on inferior orbits. In other words, Mercury and Venus, which orbit closer than the Earth, will sometimes appear to cross the disk of the Sun. Since the planets are farther away than the Moon and orbits are not perfectly aligned, these events are much rarer than solar eclipses.
Venus transited the Sun back in June of 2004, here's what that looked like:
The cycle continues 8 years later on June 2012. After that, though, you'd have to wait 105.5 years for the next transit: on December 2117, and then again 8 years later on December 2125. After that it's 121.5 years until the next one and then the cycle repeats (121.5, 8, 105.5, 8). Add up the numbers and you'll see this is a 243-year cycle. It is unlikely that anyone reading this blog today in 2012 will be alive on 2117 given the current human lifespan, so you do NOT want to miss this event.
Note that as the planet crosses the Sun it blocks out a tiny portion of the stellar disk. We're close enough to the Sun (93 million miles) that we can see the transit easily. It turns out that we can apply this same technique, though, to far more distant stars. For distant stars we can't see the disk of the star or the planet (it all just looks like a tiny point of light), but we can see how the brightness of the star changes with time. If the planet is big enough, when it crosses the star it will make the star appear just a little bit dimmer. With careful monitoring of a star's light, we can spot this change in brightness and, if periodic, infer that a planet is in the system. This can then be used to determine properties like the orbit of the planet and the planet size. This is called the transit method for extrasolar planet searches and is the way in which the Kepler spacecraft has found over a thousand candidates exoplanets.
Where can I watch the transit of Venus?
The transit will be visible from the majority of the planet, however the best place to look is in the middle of the Pacific ocean or in East Asia. People in North America can see the start of the event until the Sun sets, people in Europe and the Middle East can see the end of the event after sunrise.
Here in Chile, things don't look to promising but we have a plan (see below).
Note that it is dangerous to look directly at the Sun! You want to make sure you have proper gear: eclipse viewing glasses, solar filters for telescopes, or project the image of the Sun to a piece of paper. You can create a simple pinhole camera with a few sheets of paper and a pin (to make the hole). Here is a PDF file with some instructions on how to do that. You can find more information on how to safely observe the Sun here.
One of the best ways to experience the transit, though, is with a locally hosted star party so you can share good equipment. Here is a good website to get additional information on the transit. You can also check out this website to find out the exact times for the transit event at any location on Earth.
Why are transits so important?
Since the invention of the telescope only 6 transits of Venus have been observed. A 7th, the first one predicted using the Laws of Gravitation, took place in 1631, but was not visible from Europe and went unobserved. The 2012 transit will be the second in this new era of rapid global communications (the prior one to 2004 was in 1882). Besides the historical importance of this rare event, there's also useful science that can be carried out, such as studying the atmosphere of Venus or characterizing the transit for extrasolar planet searches. One of the coolest (and simplest) things one can do with the transit, however, is calculate the distance between the Sun and the Earth- the Astronomical Unit (AU, see my post on distance here). The precise timing of the transit in various places on the Earth, combined with some very simple geometry, can be used to estimate this distance. The basic idea is that of parallax, just like for the definition of the parsec. Once you have that down, you get the scale of the solar system and can figure out how far away the different planets are.
UPDATE: I describe the basic math and the required measurements here.
Here is a neat video about the transit, determining the distance to the Sun, and how this all relates to the search for extrasolar planets with facilities like the Kepler Space Telescope:
What about Chile?
Our own team of Chilean astronomers will be hosting a viewing event and outreach activities (including star gazing as there's a partial lunar eclipse on June 4). This will be at Easter Island since the Chilean mainland will not be able to see the transit. I encourage you to join a viewing party, either ours in the exotic Easter Island or one close to your home. You do not want to miss this!
Details for the Easter Island event can be found here (Spanish) or here (English).
Be sure to share this (and our Facebook page) with anyone you know that might be travelling to Easter Island!
What is a transit?
Just like the Moon will sometimes pass between the Earth and the Sun (causing a solar eclipse), so too do the planets on inferior orbits. In other words, Mercury and Venus, which orbit closer than the Earth, will sometimes appear to cross the disk of the Sun. Since the planets are farther away than the Moon and orbits are not perfectly aligned, these events are much rarer than solar eclipses.
 |
| Transits are rare since the orbit planes and planet positions do not always line up. |
Venus transited the Sun back in June of 2004, here's what that looked like:
 |
| The June 2004 transit of Venus |
The cycle continues 8 years later on June 2012. After that, though, you'd have to wait 105.5 years for the next transit: on December 2117, and then again 8 years later on December 2125. After that it's 121.5 years until the next one and then the cycle repeats (121.5, 8, 105.5, 8). Add up the numbers and you'll see this is a 243-year cycle. It is unlikely that anyone reading this blog today in 2012 will be alive on 2117 given the current human lifespan, so you do NOT want to miss this event.
Note that as the planet crosses the Sun it blocks out a tiny portion of the stellar disk. We're close enough to the Sun (93 million miles) that we can see the transit easily. It turns out that we can apply this same technique, though, to far more distant stars. For distant stars we can't see the disk of the star or the planet (it all just looks like a tiny point of light), but we can see how the brightness of the star changes with time. If the planet is big enough, when it crosses the star it will make the star appear just a little bit dimmer. With careful monitoring of a star's light, we can spot this change in brightness and, if periodic, infer that a planet is in the system. This can then be used to determine properties like the orbit of the planet and the planet size. This is called the transit method for extrasolar planet searches and is the way in which the Kepler spacecraft has found over a thousand candidates exoplanets.
 |
| A planet transits in front of a distant star. |
Where can I watch the transit of Venus?
The transit will be visible from the majority of the planet, however the best place to look is in the middle of the Pacific ocean or in East Asia. People in North America can see the start of the event until the Sun sets, people in Europe and the Middle East can see the end of the event after sunrise.
Here in Chile, things don't look to promising but we have a plan (see below).
 |
| June 2012 transit visibility |
Note that it is dangerous to look directly at the Sun! You want to make sure you have proper gear: eclipse viewing glasses, solar filters for telescopes, or project the image of the Sun to a piece of paper. You can create a simple pinhole camera with a few sheets of paper and a pin (to make the hole). Here is a PDF file with some instructions on how to do that. You can find more information on how to safely observe the Sun here.
One of the best ways to experience the transit, though, is with a locally hosted star party so you can share good equipment. Here is a good website to get additional information on the transit. You can also check out this website to find out the exact times for the transit event at any location on Earth.
Why are transits so important?
Since the invention of the telescope only 6 transits of Venus have been observed. A 7th, the first one predicted using the Laws of Gravitation, took place in 1631, but was not visible from Europe and went unobserved. The 2012 transit will be the second in this new era of rapid global communications (the prior one to 2004 was in 1882). Besides the historical importance of this rare event, there's also useful science that can be carried out, such as studying the atmosphere of Venus or characterizing the transit for extrasolar planet searches. One of the coolest (and simplest) things one can do with the transit, however, is calculate the distance between the Sun and the Earth- the Astronomical Unit (AU, see my post on distance here). The precise timing of the transit in various places on the Earth, combined with some very simple geometry, can be used to estimate this distance. The basic idea is that of parallax, just like for the definition of the parsec. Once you have that down, you get the scale of the solar system and can figure out how far away the different planets are.
UPDATE: I describe the basic math and the required measurements here.
Here is a neat video about the transit, determining the distance to the Sun, and how this all relates to the search for extrasolar planets with facilities like the Kepler Space Telescope:
What about Chile?
Our own team of Chilean astronomers will be hosting a viewing event and outreach activities (including star gazing as there's a partial lunar eclipse on June 4). This will be at Easter Island since the Chilean mainland will not be able to see the transit. I encourage you to join a viewing party, either ours in the exotic Easter Island or one close to your home. You do not want to miss this!
Details for the Easter Island event can be found here (Spanish) or here (English).
Chile After the Rain
Yesterday we had a lot of rain in Santiago. The day started foggy and cold:
It then started raining, with thunder and lightning, and eventually even hail.
Getting that much rain in Santiago all at once is rare, but it was necessary given that the Metropolitan Region has been in drought for the past few years. The amount of rain thus far this year (7.3 mm, including a brief rain shower in early April) still is less than the yearly average up to this date of 11.5 mm.
The news today is reporting that last night we saw flooding in some sectors with a few minor landslides. The main problem is traffic jams or "tacos" that were an hour longer than usual. The metro was very crowded and apparently also suffered from some technical problems near Manquehue that caused delays, but it's not clear if it was due to the rainy weather.
Today, however, the day is expected to be clear or partly cloudy.
I woke up this morning to see a beautiful sunrise over mountains that are now capped with snow:
Winter is truly coming...
It then started raining, with thunder and lightning, and eventually even hail.
Getting that much rain in Santiago all at once is rare, but it was necessary given that the Metropolitan Region has been in drought for the past few years. The amount of rain thus far this year (7.3 mm, including a brief rain shower in early April) still is less than the yearly average up to this date of 11.5 mm.
The news today is reporting that last night we saw flooding in some sectors with a few minor landslides. The main problem is traffic jams or "tacos" that were an hour longer than usual. The metro was very crowded and apparently also suffered from some technical problems near Manquehue that caused delays, but it's not clear if it was due to the rainy weather.
 |
| The lack of proper drainage in Santiago causes flooding very quickly. Credit: instagr.am/ maritesanz |
Today, however, the day is expected to be clear or partly cloudy.
I woke up this morning to see a beautiful sunrise over mountains that are now capped with snow:
Winter is truly coming...
Wednesday, April 25, 2012
Astronomy: Observing at APEX
Last week, I went to San Pedro de Atacama in Northern Chile to participate in service observations at APEX Observatory. APEX stands for the Atacama Pathfinder Experiment and is a modified ALMA prototype 12-meter antenna located at the Chajnantor Plateau at a 5100-meter (16,000-feet) altitude. Like ALMA, APEX observes at submillimeter wavelengths and so requires such a high and dry site to observe.
 |
| The 12-meter diameter APEX radiotelescope |
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