video of 4 exoplanets orbiting their host star

[oxmixmudd]

A while back when Jorge still trolled these halls we all had an extended discussion with him about the validity of the claim that we were discovering exo-planets orbiting stars. Over time he gradually ceded these were probably planets after all, but at the core of much of his early argumentation was something akin to 'seeing is believing' in that he mocked the reliability of the indirect methods being used to tease the planets out. Radial velocity and transit where key methods of the Early discoveries.

Here is a link to a timelapse 'video' of 4 planets orbiting their host star about 130 light years from here. Keep in mind the observed motions took place back a little before Edwin Hubble was born (the discoverer of the red-shift/distance correlation for galaxies and the pioneer in the use of Cepheid Variables as a distance scale, providing one of the first estimates of the Andromeda Galaxy's distance)


4 planets orbiting their star

Jim

[Sparko]

cool

[Scrawly]

And all the earthlings say: "Amen"!

[shunyadragon]

Fantastic!!!!

That is where the 2000 pound kangaroos came from.

[TheLurch]

Also worthy of note: we've only just passed 20 years since the first discovery of an exoplanet (it was 1995). Now we know of thousands of them. And, assuming our corner of the galaxy isn't unusual, hundreds of billions of them in the Milky Way alone.

We live in amazing times, from a science perspective. Makes me want to find the guy who wrote The End of Science and ask him "seriously?"

[oxmixmudd]

Also worthy of note: we've only just passed 20 years since the first discovery of an exoplanet (it was 1995). Now we know of thousands of them. And, assuming our corner of the galaxy isn't unusual, hundreds of billions of them in the Milky Way alone.

We live in amazing times, from a science perspective. Makes me want to find the guy who wrote The End of Science and ask him "seriously?"

It is a bit interesting to watch Star Trek TOS episodes these days and realize - yes, there are, in fact that many planets out there. When the show aired, the idea that a large percentage of the stars might have planets around them was pure speculation. And we are just beginning to be able to detect what would be 'class M' planets in ST parlance. These are indeed amazing times.

Jim

[tabibito]

Also worthy of note: we've only just passed 20 years since the first discovery of an exoplanet (it was 1995). Now we know of thousands of them. And, assuming our corner of the galaxy isn't unusual, hundreds of billions of them in the Milky Way alone.

We live in amazing times, from a science perspective. Makes me want to find the guy who wrote The End of Science and ask him "seriously?"

Last I heard, the Solar System IS unusual - the gas giants (which should be close to the sun) and the rocky type planets are not in the most common locations. Of course, it's been a couple of years since I last looked at the findings - and it is a fast changing field.

[TheLurch]

Last I heard, the Solar System IS unusual - the gas giants (which should be close to the sun) and the rocky type planets are not in the most common locations. Of course, it's been a couple of years since I last looked at the findings - and it is a fast changing field.

It's unusual in comparison to the exosolar systems that we've characterized. But the fact is that we've barely scratched the surface, purely due to how things are detected. Direct imaging only works for gas giants far from the star. Radial velocity works best for heavy planets close to the star. Kepler required multiple orbits before confirming that a star's dimming was caused by a planet; since it only imaged for a few years, it couldn't pick up anything much further out than the Earth.

Combined, these limits mean that we've primarily looked at exosolar systems with planets closer to their host star than earth is to the sun. So, we don't really have a good perspective on what the full systems look like. It's entirely possible that some of them do look a bit more like our own.

Kinda wish NASA would just send something up that's like Kepler, but with enough backup hardware to let it run for 30 years.

[oxmixmudd]

Last I heard, the Solar System IS unusual - the gas giants (which should be close to the sun) and the rocky type planets are not in the most common locations. Of course, it's been a couple of years since I last looked at the findings - and it is a fast changing field.

We know about very few rocky planets at this point. But just statistically, there should be at least as many as the gas giants we've detected. And as TheLurch pointed out, our detection techniques right now favor gas giants in two positions (1) close to their parent star (radial velocity and transit) (2) very large and far enough from the parent star to be resolved in a telescope (as in this video). With by far the bias being (1) because of the time it takes to tease out longer orbits from the observations (radial velocity) and the likelihood of a transit decreasing with distance.

And then there is the fact that there are a few known star systems with Jupiter sized planets at Jupiter like distances. So, if the current number of finds implies 100 billion stars with planetary systems in the Milky Way, then our solar system being 1 in a thousand means there are likely 100 million solar system analogues out there just in this galaxy alone. If a place like Earth is 1 in a thousand of those, we still are looking at over 100,000 planets similar to Earth in this galaxy.

Though I will admit 1 in a million would seem to make our galaxy a bit sparser in terms of class M planets than what seems implied in Star Trek TOS


Jim