This is a short post to let you know that the results of the Hetu'u Global Network have been officially published in Astronomy Education Review (AER)! You can see the article here.
More details after the jump.
Showing posts with label Transit of Venus. Show all posts
Showing posts with label Transit of Venus. Show all posts
Thursday, December 6, 2012
Hetu'u Global Network Results Published
This is a short post to let you know that the results of the Hetu'u Global Network have been officially published in Astronomy Education Review (AER)! You can see the article here.
More details after the jump.
Wednesday, June 20, 2012
The Transit of the Earth... from Mars!
Several weeks ago we were witness to one of the rarest, yet predictable, astronomical events known: the transit of Venus. The next such transit will be in the year 2117. You can always catch the next transit of Mercury, though. These are far more common with 13-14 events per century: the next one is May 9, 2016. However, you do need a telescope to see it as Mercury is much smaller.
Perhaps you are now hooked on transits and want to catch an even more exciting event. You may actually have already seen the November 2006 Mercury transit. How about a (near) simultaneous transit of both Venus and Mercury? Good luck: the next one will be around September in the year 13,425 AD.
Perhaps it's best to focus on something that may happen sooner? Enter the transit of the Earth!
If you think Mercury and Venus transiting is exciting, then check out this simulation of transit of the Earth (and Moon!)... from Mars!
Perhaps you are now hooked on transits and want to catch an even more exciting event. You may actually have already seen the November 2006 Mercury transit. How about a (near) simultaneous transit of both Venus and Mercury? Good luck: the next one will be around September in the year 13,425 AD.
Perhaps it's best to focus on something that may happen sooner? Enter the transit of the Earth!
If you think Mercury and Venus transiting is exciting, then check out this simulation of transit of the Earth (and Moon!)... from Mars!
Tuesday, June 12, 2012
Easter Island: Transit of Venus (2/3)
This is the second of a three part post series on our recent trip to Easter Island. Previously I wrote about the outreach activities we did on the days leading up to the transit. In this post I describe the main event itself: the transit of Venus.
I've previously talked about the transit of Venus (here) and described the math involved in determining the distance (here). Hence, I'll skip the overview and jump right into the details.
I've previously talked about the transit of Venus (here) and described the math involved in determining the distance (here). Hence, I'll skip the overview and jump right into the details.
Sunday, June 10, 2012
Easter Island: Outreach Activities (1/3)
This past week I've been with a group of astronomers on Easter Island to do outreach, observe the transit of Venus, and do some tourism. This is the first of a 3 post series describing our adventures. Part 1 is a description of the outreach activities we did at Easter Island. Part 2 describes our viewing of the transit of Venus along with our distance estimate, and Part 3 is about the places we visited.
Tuesday, June 5, 2012
The Day of the Transit of Venus
Today is June 5, 2012 (for me, for others it will be June 6). This is the day that Venus passes in front of the Sun in a rare alignment resulting in a transit. This is similar to an eclipse, though Venus will only block ~1/30th of the Sun's disk. Unlike an eclipse, a transit of Venus is an extremely rare event. The next one will be more than a century from now: December 2117.
I had previously written about the transit (here) and detailed some of the math (here) involved in estimating the distance to the Sun. My prior post details one of the outreach activities I created as part of the event.
Today, this post is short and intended only to say one thing: WATCH IT!
This is a scheduled post so hopefully it goes out on time (regardless, the transit lasts for 6 hours).
If it's cloudy or you otherwise can't see the event, here's a short list of websites that will provide live webcasts so you can watch this unique event online (unfortunately, Team Hetu'u will not have a live web feed):
If one link doesn't work, try another! For a larger list, see the Bad Astronomy post here.
Clear skies!
I had previously written about the transit (here) and detailed some of the math (here) involved in estimating the distance to the Sun. My prior post details one of the outreach activities I created as part of the event.
Today, this post is short and intended only to say one thing: WATCH IT!
This is a scheduled post so hopefully it goes out on time (regardless, the transit lasts for 6 hours).
If it's cloudy or you otherwise can't see the event, here's a short list of websites that will provide live webcasts so you can watch this unique event online (unfortunately, Team Hetu'u will not have a live web feed):
If one link doesn't work, try another! For a larger list, see the Bad Astronomy post here.
Clear skies!
Saturday, June 2, 2012
The Solar System at Easter Island
By now, you've probably heard about the transit of Venus on June 5-6, 2012. I wrote a short post (here) describing it and a second one (here) describing one method to estimate the distance to the Sun using the transit. Although Chile won't see the transit, a group of us will be traveling to Easter Island to watch it from there (technically *have* travelled since this post was scheduled in advance).
We've created a whole outreach plan for our time at Easter Island, which includes a two-day workshop at the local museum (with talks by the astronomers), school visits the following day, observing the partial lunar eclipse, and the transit of Venus itself on June 5.
One of the things I prepared was an activity on the scale of the solar system specifically for the residents of Easter Island.
We've created a whole outreach plan for our time at Easter Island, which includes a two-day workshop at the local museum (with talks by the astronomers), school visits the following day, observing the partial lunar eclipse, and the transit of Venus itself on June 5.
One of the things I prepared was an activity on the scale of the solar system specifically for the residents of Easter Island.
Sunday, May 20, 2012
Measuring the Distance to the Sun with the Transit of Venus
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.
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).
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