Exosolar planets are planets outside our solar system. They are planets that are hundreds of light-years away. These are planets that are usually discovered by the way they distort the light of the stars around them--no clear photos here.
So, how do scientists determine what a planet is made of?
The answer involves a little math. To get the density of a planet, one must know the mass and volume, since the formula for density is mass divided by volume.
Determining an exosolar planet's mass involves observing the star it orbits. Because of their gravitational pull on one another, the star will "wobble" slightly. By measuring how much the planet makes the star "wobble", it's then possible to determine an accurate mass for the planet.
Volume calculations involve making observations while one celestial body eclipses another. The degree to how much the light of one is dimmed by another makes for a good estimate of volume.
Knowing both of these figures allows for the calculation of density.
Furthermore, the general atmospheric makeup can be determined, if one has a spectrograph and light filtering past the observed planet. If certain frequencies are missing, then that's a sign they have been absorbed by the planet's atmosphere, and thus are present.
Citations:
Holladay, April. (2006). How scientists determine the composition of each planet. Retrieved February 6 2009, from: http://www.usatoday.com/tech/columnist/aprilholladay/2006-09-25-measuring-planets_x.htm
Strobel, Nick. (2007) Planetary science. Retrieved February 6 2009, from: http://www.astronomynotes.com/solarsys/s2.htm
Friday, February 6, 2009
Thursday, February 5, 2009
A new type of planet
To pick up from yesterday, what was the planet that was discovered?
As it's sometimes said, one instance is an anomaly, two might be coincidence and three is a pattern. The planet that was discovered by the HATnet, HAT-P-1, was the second of the type of planet that has been termed the puffy planet, a type of gas giant. A third was discovered in 2007.
Puffy planets are huge. They are larger than even Jupiter. But surprisingly, they are less dense than even Saturn, which is often said famously to be able to float in a bathtub. To quote Bakos in the official press release, ""This planet is about one-quarter the density of water. In other words, it's lighter than a giant ball of cork!"
The mystery involved with these planets, now, is to discover exactly how they are formed. Within current astronomical theories, there is no explanation for them. There is yet another mystery, as well: they are what is often term as "hot Jupiters", or very hot gas giants. How they have remained so large and hot--given they are not by any means young planets--remains puzzling.
Tomorrow, the methodology used to determine the characteristics of the puffy planets, or, "how can they tell how dense something so far away is, anyway?"
Citations:
Chang, Kenneth. (2006). Puzzling puffy planet, less dense than cork, is discovered. Retrieved February 5 2009, from: http://www.nytimes.com/2006/09/15/science/space/15planet.html?ex=1315972800&en=3646d4e6a10ec036&ei=5089&emc=rss
European Space Agency. (2007). COROT discovers its first exoplanet and catches scientists by surprise. Retrieved February 5 2009, from: http://www.esa.int/esaCP/SEMCKNU681F_index_0.html
Harvard-Smithsonian Center for Astrophysics. (2006) Strange new planet baffles astronomers. Retrieved February 5 2009, from: http://www.cfa.harvard.edu/press/2006/pr200624.html
As it's sometimes said, one instance is an anomaly, two might be coincidence and three is a pattern. The planet that was discovered by the HATnet, HAT-P-1, was the second of the type of planet that has been termed the puffy planet, a type of gas giant. A third was discovered in 2007.
Puffy planets are huge. They are larger than even Jupiter. But surprisingly, they are less dense than even Saturn, which is often said famously to be able to float in a bathtub. To quote Bakos in the official press release, ""This planet is about one-quarter the density of water. In other words, it's lighter than a giant ball of cork!"
The mystery involved with these planets, now, is to discover exactly how they are formed. Within current astronomical theories, there is no explanation for them. There is yet another mystery, as well: they are what is often term as "hot Jupiters", or very hot gas giants. How they have remained so large and hot--given they are not by any means young planets--remains puzzling.
Tomorrow, the methodology used to determine the characteristics of the puffy planets, or, "how can they tell how dense something so far away is, anyway?"
Citations:
Chang, Kenneth. (2006). Puzzling puffy planet, less dense than cork, is discovered. Retrieved February 5 2009, from: http://www.nytimes.com/2006/09/15/science/space/15planet.html?ex=1315972800&en=3646d4e6a10ec036&ei=5089&emc=rss
European Space Agency. (2007). COROT discovers its first exoplanet and catches scientists by surprise. Retrieved February 5 2009, from: http://www.esa.int/esaCP/SEMCKNU681F_index_0.html
Harvard-Smithsonian Center for Astrophysics. (2006) Strange new planet baffles astronomers. Retrieved February 5 2009, from: http://www.cfa.harvard.edu/press/2006/pr200624.html
Wednesday, February 4, 2009
On types of planets
Basically, there are two broad categories of planets. There are rocky, or terrestrial planets, and there are gaseous planets, which are also termed gas giants. An example of the former in our solar system would be Mars, and of the latter, Jupiter.
More precisely, a terrestrial planet may or may not possess an atmosphere. They have a definite solid surface somewhere, unlike gas giants, and always have some sort of metallic core. There are finer subdivisions of terrestrial planets into types depending on their composition, whether they are considered a planet proper or a dwarf (remember the argument about Pluto's status a few years back?), their temperature and so forth.
A gas giant generally lives up to its name. They are large; Space.com lists Jupiter as being able to contain around 1,500 Earths. Most noticeably, they possess a thick atmosphere which makes up the majority of their mass. The surface of a gas giant is not easily detectable, and may not be solid.
They are generally divided into two types. There are the "normal" gas giants, which mostly consist of hydrogen and helium, such as Saturn and Jupiter in our Solar System. Then there are "ice giants", which consist mainly of water, methane and ammonia. These are represented by Neptune and Uranus in our Solar System.
But they're not the only types of planet. So what did Gáspár Bakos' network discover? That'll have to wait until tomorrow.
Web Resources:
Arnett, Bill. (2009). Jupiter. Retrieved February 4 2009, from: The Nine Planets
Solar System Tour: http://www.nineplanets.org/jupiter.html
Arnett, Bill. (2009). Jupiter. Retrieved February 4 2009, from: The Nine Planets
Solar System Tour: http://www.nineplanets.org/mars.html
Arnett, Bill. (2009). Jupiter. Retrieved February 4 2009, from: The Nine Planets
Solar System Tour: http://www.nineplanets.org/neptune.html
Comments: Worth browsing. Good overview of the Solar System.
Space.com. (2009) Virtual Space Tour. Retrieved February 4 2009 from:
http://www.space.com/php/popup/virtualspacetour/noad_astropedia.php
Comments: Also not a bad starting point; this one's more interactive. Space.com in general is a good go-to for space and astronomy news.
More precisely, a terrestrial planet may or may not possess an atmosphere. They have a definite solid surface somewhere, unlike gas giants, and always have some sort of metallic core. There are finer subdivisions of terrestrial planets into types depending on their composition, whether they are considered a planet proper or a dwarf (remember the argument about Pluto's status a few years back?), their temperature and so forth.
A gas giant generally lives up to its name. They are large; Space.com lists Jupiter as being able to contain around 1,500 Earths. Most noticeably, they possess a thick atmosphere which makes up the majority of their mass. The surface of a gas giant is not easily detectable, and may not be solid.
They are generally divided into two types. There are the "normal" gas giants, which mostly consist of hydrogen and helium, such as Saturn and Jupiter in our Solar System. Then there are "ice giants", which consist mainly of water, methane and ammonia. These are represented by Neptune and Uranus in our Solar System.
But they're not the only types of planet. So what did Gáspár Bakos' network discover? That'll have to wait until tomorrow.
Web Resources:
Arnett, Bill. (2009). Jupiter. Retrieved February 4 2009, from: The Nine Planets
Solar System Tour: http://www.nineplanets.org/jupiter.html
Arnett, Bill. (2009). Jupiter. Retrieved February 4 2009, from: The Nine Planets
Solar System Tour: http://www.nineplanets.org/mars.html
Arnett, Bill. (2009). Jupiter. Retrieved February 4 2009, from: The Nine Planets
Solar System Tour: http://www.nineplanets.org/neptune.html
Comments: Worth browsing. Good overview of the Solar System.
Space.com. (2009) Virtual Space Tour. Retrieved February 4 2009 from:
http://www.space.com/php/popup/virtualspacetour/noad_astropedia.php
Comments: Also not a bad starting point; this one's more interactive. Space.com in general is a good go-to for space and astronomy news.
Tuesday, February 3, 2009
On HATnet
Gáspár Bakos' major contribution to the astronomical sciences is the creation of HATnet, which is short for Hungarian-made Automated Telescope. This system, as described in the previous link, originated to track certain bright variable objects (which includes both stars and planets, among others) in the northern hemisphere's sky, without any direct assistance necessary from humans.
Bakos developed the prototype of the telescopes currently in use while an undergraduate student in Hungary. Interestingly, it was home-made; it was built using camera components.
Through this telescope network, which now includes locations in Israel, Hawaii and Arizona, an entirely new class of planet was detected in 2006.
So what's the big deal about the planets? For the next three days, I'll try to cover the basics of astronomy, the planet his network discovered, as well as the difficulty involved with detecting extrasolar planets.
Bakos developed the prototype of the telescopes currently in use while an undergraduate student in Hungary. Interestingly, it was home-made; it was built using camera components.
Through this telescope network, which now includes locations in Israel, Hawaii and Arizona, an entirely new class of planet was detected in 2006.
So what's the big deal about the planets? For the next three days, I'll try to cover the basics of astronomy, the planet his network discovered, as well as the difficulty involved with detecting extrasolar planets.
Monday, February 2, 2009
Hi, this is my blog for LS.556.W1, Bibliography of the Sciences. In these entries, I plan to write about a brilliant young scientist, Gáspár Bakos. Popular Science named him, among several others, one of the most promising young scientists of 2007. He build his own telescope network, and through it, discovered a new type of planet.
More to come later.
More to come later.
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