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A Second Planet May Orbit Earth's Nearest Neighboring Star

25 points by headalgorithm 8y ago

acqq 8y ago
> Midway in mass and size between Earth and giant worlds like Neptune, such worlds may either be mostly gassy worlds offering slim chances for life as we know it, or instead super-sized versions of our own habitable, rocky world. However: > Astronomers say they may have detected a second planet ... with a minimum mass roughly six times that of our planet’s. If it's a planet 6 times more massive than Earth, it's a gaseous planet, and nothing like Earth: https://www.forbes.com/sites/startswithabang/2016/11/08/is-earth-our-solar-systems-missing-super-earth/ https://www.forbes.com/sites/startswithabang/2016/11/08/is-e... So don't expect that humans will ever land on that, even if they reach it once (for it rotating around the nearest star). Apparently "super-sized versions of our own habitable, rocky world" can be just slightly bigger than Earth.
- gassyEarth 8y ago
  Doesn't 6 times the mass get ~6 times the gravity, if we're talking about a rocky planet of comparable density? If I weigh 600 Kg on a super-sized version of earth, it doesn't matter what amount of water or atmosphere is present. It's not habitable, even if it's a temperate 30 degrees celsius, with refreshing sun showers and a briney primordial soup.
  - acqq 8y ago
    "6 times the mass get ~6 times the gravity, if we're talking about a rocky planet of comparable density?" There's no such thing, apparently, see the link I've already posted. According to the latest research, six times the Earth mass the planet is gaseous (Neptune-like). The limit over which the planet is Neptune-like is just two times Earth mass, which corresponds to just a little bigger radius than Earth's: "a world that's 2.0 Earth masses and rocky will only be about 25% larger in radius than Earth; larger than that and you're probably Neptune-like, with a massive hydrogen/helium envelope." https://www.universetoday.com/22070/surface-of-neptune/ https://www.universetoday.com/22070/surface-of-neptune/ "In short, there is simply no way one could stand on the “surface of Neptune”, let alone walk around on it."
jcims 8y ago
From my stubby pencil work it seems that the apparent diameter of this planet would be within an order of magnitude of the black hole image from earlier this week (~120 vs 40 micro arcseconds), which is 3+ orders of magnitude smaller than the resolving power of even our largest optical telescopes. I have a feeling ill never see an image of another planet in this life. :(
- hansjorg 8y ago
  https://en.m.wikipedia.org/wiki/List_of_directly_imaged_exoplanets https://en.m.wikipedia.org/wiki/List_of_directly_imaged_exop... https://en.m.wikipedia.org/wiki/Methods_of_detecting_exoplanets#Direct_imaging https://en.m.wikipedia.org/wiki/Methods_of_detecting_exoplan...
  - jcims 8y ago
    I guess what I'm hoping for is something akin to Hubble's photo of Pluto. A blurry blob with patches of color. In the animated image at the top right of the page you linked, those planets are between 14 and 69 AU from their star. Let's pick the one at about 5 o'clock, it's the second most distant at about 25AU, or ~2.5 billion miles from the little yellow star. Wikipedia says its ~1.3 times the radius of Jupiter, so let's round up to get even numbers and say it's 125,000 miles in diameter. That means the actual scale size of that planet is 1/20,000th the distance between those two dots in the image, meaning that blurry dot is about 2,000 times as large as the planet itself. We have a long way to go.
- jessriedel 8y ago
  The telescopes of the Event Horizon Telescope were all within an Earth diameter of each other. There's nothing but a bit of money stopping us from doing the same trick with multiple telescopes dispersed around the Sun, say, around the Earth's orbital path. That would increase the resolution by the ratio of 1 AU to Earth's radius, a factor of over 20,000.

25 points by headalgorithm 8y ago

acqq 8y ago

> Midway in mass and size between Earth and giant worlds like Neptune, such worlds may either be mostly gassy worlds offering slim chances for life as we know it, or instead super-sized versions of our own habitable, rocky world. However: > Astronomers say they may have detected a second planet ... with a minimum mass roughly six times that of our planet’s. If it's a planet 6 times more massive than Earth, it's a gaseous planet, and nothing like Earth: https://www.forbes.com/sites/startswithabang/2016/11/08/is-earth-our-solar-systems-missing-super-earth/ https://www.forbes.com/sites/startswithabang/2016/11/08/is-e... So don't expect that humans will ever land on that, even if they reach it once (for it rotating around the nearest star). Apparently "super-sized versions of our own habitable, rocky world" can be just slightly bigger than Earth.

gassyEarth 8y ago
Doesn't 6 times the mass get ~6 times the gravity, if we're talking about a rocky planet of comparable density? If I weigh 600 Kg on a super-sized version of earth, it doesn't matter what amount of water or atmosphere is present. It's not habitable, even if it's a temperate 30 degrees celsius, with refreshing sun showers and a briney primordial soup.
- acqq 8y ago
  "6 times the mass get ~6 times the gravity, if we're talking about a rocky planet of comparable density?" There's no such thing, apparently, see the link I've already posted. According to the latest research, six times the Earth mass the planet is gaseous (Neptune-like). The limit over which the planet is Neptune-like is just two times Earth mass, which corresponds to just a little bigger radius than Earth's: "a world that's 2.0 Earth masses and rocky will only be about 25% larger in radius than Earth; larger than that and you're probably Neptune-like, with a massive hydrogen/helium envelope." https://www.universetoday.com/22070/surface-of-neptune/ https://www.universetoday.com/22070/surface-of-neptune/ "In short, there is simply no way one could stand on the “surface of Neptune”, let alone walk around on it."

jcims 8y ago

From my stubby pencil work it seems that the apparent diameter of this planet would be within an order of magnitude of the black hole image from earlier this week (~120 vs 40 micro arcseconds), which is 3+ orders of magnitude smaller than the resolving power of even our largest optical telescopes. I have a feeling ill never see an image of another planet in this life. :(

hansjorg 8y ago
https://en.m.wikipedia.org/wiki/List_of_directly_imaged_exoplanets https://en.m.wikipedia.org/wiki/List_of_directly_imaged_exop... https://en.m.wikipedia.org/wiki/Methods_of_detecting_exoplanets#Direct_imaging https://en.m.wikipedia.org/wiki/Methods_of_detecting_exoplan...
- jcims 8y ago
  I guess what I'm hoping for is something akin to Hubble's photo of Pluto. A blurry blob with patches of color. In the animated image at the top right of the page you linked, those planets are between 14 and 69 AU from their star. Let's pick the one at about 5 o'clock, it's the second most distant at about 25AU, or ~2.5 billion miles from the little yellow star. Wikipedia says its ~1.3 times the radius of Jupiter, so let's round up to get even numbers and say it's 125,000 miles in diameter. That means the actual scale size of that planet is 1/20,000th the distance between those two dots in the image, meaning that blurry dot is about 2,000 times as large as the planet itself. We have a long way to go.
jessriedel 8y ago
The telescopes of the Event Horizon Telescope were all within an Earth diameter of each other. There's nothing but a bit of money stopping us from doing the same trick with multiple telescopes dispersed around the Sun, say, around the Earth's orbital path. That would increase the resolution by the ratio of 1 AU to Earth's radius, a factor of over 20,000.