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Earth-like planet a result of a gas giant getting swallowed?

12 Jan

Some interesting questions have been brought up by these recent Kepler discoveries. Stars like our sun usually expand to become red giants and then become compact again as helium fusion begins in their cores. Sometimes, the hydrogen is stripped off of the star (by another star for example), leaving just the helium-fusing core behind, compact and very hot. A star in this state has been observed (a hot B subdwarf), where the hydrogen was stripped off, except there is no companion star to have taken the hydrogen away. It’s a cosmic mystery: What happened to the hydrogen?

This star system has several recently-discovered small, (presumed) rocky planets orbiting it. The emerging theory is that when the star expanded to become a red giant, it consumed several gas giants with orbits close enough to be swallowed. When the star contracted again to enter the helium fusion phase, the planets reemerged as small, rocky planets, stripped of their gaseous exteriors. The disruption resulting from the planetary collisions with the star could have stripped the star of some of its hydrogen, causing it to be in the state we now find it: very hot, with several small, rocky planets locked in a tight orbit. Time will tell if this theory is correct. There is so much we don’t understand about the birth and evolution of stars and planets.

Article here.


More earth-sized planets discovered

11 Jan

Scientists have spotted 2 earth-sized planets in an extremely tight orbit around a star very like our own sun.

Article here.

First habitable-zone planet discovered

3 Jan

Observing planets outside our solar system has always been a challenge. The only way to spot one is when a planet crosses in front of its star and causes a fluctuation in the light emitted from that star. Such small fluctuations are difficult to observe from earth, where conditions have to be just right and atmospheric effects accounted for. In the past, we have been able to spot mostly large, Jupiter-sized planets. So, in 2009, NASA launched the Kepler spacecraft, whose only purpose is to observe planets outside our solar system from space, free from atmospheric troubles.

The data are flowing back fast. In fact there have been over 200 earth-sized planets spotted that are waiting to be confirmed by earth-based telescopes before announced. Forty-eight of the planetary candidates lie in the “habitable zone” of their solar systems, which means that the temperatures are right for liquid water to be sustained on the surface. That doesn’t mean they do have liquid water; it just means that it is a possibility. We are waiting on the ground telescopes to confirm these planetary candidates. And then we can get to work on determining their densities, and therefore what they’re made of.

Kepler 22-B is the first confirmed habitable-zone planet discovered outside our solar system. It is on the inside of the habitable zone. Were it in our solar system, it would be somewhere between Earth and Venus.

You may remember the discovery of a planet closely orbiting a double-sun (Kepler 16-B), confirmed by ground telescopes in Septemberish of 2011. Stay tuned for more exciting planetary discoveries from Kepler (there were several exciting ones over Christmas break).

Sense of scale and Saturn’s storm

18 Nov

It’s difficult to comprehend the size of objects when they are very large or very small. Check out this site that gives you a sense of the size of cells, viruses, and other biological bits and bobs (you must be flash enabled).

Also, there are some very cool photos of a giant storm on Saturn here. To be honest, I’m not exactly sure what it means to be a storm on a gaseous planet where there are large-scale currents and violent swirling eddies in the different layers of gas all the time. But the pictures are very cool. It looks just like the experiment you see at science centers where you have a big flat circle full of a colored liquid, and you spin it in different directions to see the chaotic motion.

Russian probe stranded in earth orbit

11 Nov

The Russian probe Phobos-Grunt was intended to go to Mars, orbit it for awhile, then land on Mars’ moon Phobos, where it would have collected soil samples and then returned to earth in 2014. But the probe is currently stranded in orbit around the earth. The craft experienced engine failure very soon after launch. The Russian Space Agency says that they have 3 days to remotely get the engine running again and the probe back on track before its batteries die. Russian has had 3 failed attempts to land on the moon Phobos in the last 25 years, and all hopes are riding on this probe. Hopefully they will get this thing working again.

Phobos-Grunt is also carrying a Chinese satellite, and an experiment being conducted by the Planetary Society trying to see if extremophiles can survive in the low pressures of space.

Image courtesy of Russian Space Agency

Volcanoes on other planets

22 Oct

To wrap up Volcano Week at Physics Fascination, I just want to note that there are volcanoes on planetary objects other than earth. Check out this photo of the massive Tvashtar volcano on Jupiter’s moon, Io. Or watch a video of images here. Amazing.

Surfacing volcanoes made the air we breath

20 Oct

The earth didn’t always have oxygen in it’s atmosphere. Oxygen appeared in earth’s atmosphere at about the same time that blue-green algae appeared in the earth’s oceans, which makes sense since the algae takes in carbon dioxide and spits out oxygen. We’ve known that bit for a while–but as we learned more about the exact times that these events occurred, we started to scratch our heads a bit. The ocean algae actually appeared quite a bit earlier than the oxygen in the earth’s atmosphere.

So why the time lapse? It turns out that the atmosphere became oxygenated at the same time that much of the continental crust formed and the ocean receded. Volcanoes that were once under water became exposed to air. When volcanoes are exposed to air, the gas they spew is a bit different from what comes out of an underwater volcano. It turns out that underwater volcanoes spew a lot more H2S than land volcanoes, and that H2S traps oxygen and removes it from the atmosphere. So when the volcanoes were all underwater and spitting out this oxygen-trapping substance, the atmosphere of the earth could not become fully oxygenated. When the volcanoes emerged from the oceans, they no longer impeded the building up of oxygen in our atmosphere and we got our ozone layer. At least that’s the theory. It corresponds pretty well with other evidence from that time period. Read more here.

We really understand so little about our earth and how it was formed.