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Four Earth-sized planets detected orbiting the nearest sun-like star

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Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#131

Post by ExactoKnight »

2845197541 wrote: post #125
ExactoKnight wrote: post #101

I am flabbergasted that as a society we aren't rushing to build a 100 metre wide telescope mirror large enough for us to directly image the spectra of the potentially habitable exoplanets around us. A telescope this large could tell us whether any of these potentially habitable planets contain oxygen, and thus, biological processes. Yet thanks to funding cuts in science the biggest telescope we have in the pipeline r…

>Why are we here? What do you mean by this?

Finding the existence of life on another planet holds MAJOR implications for many organized and unorganized religions. It would tell us whether abiogenesis and life is common, or something truly unique.

So while discovering life on another planet wouldn't answer exactly "why we are here", it would go a hell of a long way in shaping our answers to that question.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#132

Post by Balgair »

saganus wrote: post #105
ExactoKnight wrote: post #101

I am flabbergasted that as a society we aren't rushing to build a 100 metre wide telescope mirror large enough for us to directly image the spectra of the potentially habitable exoplanets around us. A telescope this large could tell us whether any of these potentially habitable planets contain oxygen, and thus, biological processes. Yet thanks to funding cuts in science the biggest telescope we have in the pipeline r…

Isn't building a 100m telescope incredibly hard? does that kind of technology exist already? (I genuinely don't know). Also, what would the effect of the atmosphere be in such a large telescope? would a bigger mirror increase or decrease the effects of Earth's atmosphere for these kind of observations?

Noise is noise. If you put gain on the signal in general, you'll put gain on the noise too. That's why James Webb is in space and the 30 Meter Telescope (TMT) is in Hawaii, less atmosphere and clear air means less noise inputted. Still, the TMT is pretty darn good. So yes, you are correct, bigger telescope means more noise (in gestalt) while in atmosphere. THe reason bigger is better is because you can resolve smaller angles. The Fourier treatment of optics is useful here. The radius of your lenses/reflectors sets the limit of the higher spatial frequency. Low spatial frequencies pass through small lenses/refectors and high spatial frequencies pass through larger ones. Therefore the bigger the telescope, the more higher order spatial frequencies you can collect. https://en.wikipedia.org/wiki/Fourier_optics

Why not a 100 Meter Telescope? Cost and engineering. With these retro reflectors getting so big, you have to worry a lot about thermal expansion and differential levels of it across the whole surface. Also, the structure to hold it has to be monitored really closely in real time to make sure the calculations are accurate. It's not easy. Also, with modern adaptive optics, you'll have apply all the little piezo-motors across the entire surface which goes as the square of the radius, so costs go up geometrically (plus about 15% more for each doubling in surface area due to cabling, power issues, larger facilities with thicker steel beams, more janitors, etc.). If the TMT costs X, then the 100-MT should cost about 11X, and with the 15% doubling factor, its ~15X for only a 3X increase in radius.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#133

Post by cetalingua »

ExactoKnight wrote: post #101

I am flabbergasted that as a society we aren't rushing to build a 100 metre wide telescope mirror large enough for us to directly image the spectra of the potentially habitable exoplanets around us. A telescope this large could tell us whether any of these potentially habitable planets contain oxygen, and thus, biological processes. Yet thanks to funding cuts in science the biggest telescope we have in the pipeline r…

>Why are we here, and are we alone

How about we first at least try to understand life on Earth? We are definitely not alone, there are other conscious beings on this planet. After decades of studies we still have no idea what a humpback whale's song means. Bottlenose dolphins have at least 2 if not 3, sound generating mechanisms that could work simultaneously. The amount of information that can be encoded is enormous. Yet, we are still to learn what a single dolphin's call means. We know the function of some meercats' calls or praire dogs' calls, but despite 60 years of research we are yet to decode a function of at least one dolphin call, let alone something more complex like beluga chatter or a humpback song.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#134

Post by Zitrax »

tadfisher wrote: post #65
hinkley wrote: post #28

Earlier quoted context omitted.

Seems like it would have to be. If you've worked out from the wobble what the mass and orbit are it would stand to reason you've either calculated or at least stated an assumption regarding the inclination.

You can put a lower bound on both, but inclination introduces an unknown upper bound.

But shouldn't they have _some_ upper bound ? I guess for example that it's unlikely they are larger than 100 Earth masses since they call them Earth-sized.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#135

Post by ExactoKnight »

rsync wrote: post #130
baron816 wrote: post #37

Ok, let's assume we find a warm, watery planet like Earth's within ~20 light years, and we figure out a way to travel >= 50% the speed of light, making it somewhat reasonable to get there. If the planet's gravity is greater than 10% different from Earth's, or its Day/Night cycle is much different from Earth's, wouldn't it still be a nightmare to live on. Anatomically modern humans have lived on Earth for 200,000 year…

"Anatomically modern humans have lived on Earth for 200,000 years, and the creatures we descended from have lived on Earth for 541 million years. Stuff as dumb as the moon cycles affect us. How are we going to live somewhere that isn't exactly Earth?" To further your (good) point about gravitational and diurnal differences, it is worth also considering the experience of native americans in the face of novel (to them)…

It depends wouldn't it? If the biology and chemistry of those organisms prove to be completely different (e.g, by not being carbon based), then couldn't their bacteria prove to be utterly inert in relation to our bodies?

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#136

Post by goatlover »

saganus wrote: post #105
ExactoKnight wrote: post #101

I am flabbergasted that as a society we aren't rushing to build a 100 metre wide telescope mirror large enough for us to directly image the spectra of the potentially habitable exoplanets around us. A telescope this large could tell us whether any of these potentially habitable planets contain oxygen, and thus, biological processes. Yet thanks to funding cuts in science the biggest telescope we have in the pipeline r…

Isn't building a 100m telescope incredibly hard? does that kind of technology exist already? (I genuinely don't know). Also, what would the effect of the atmosphere be in such a large telescope? would a bigger mirror increase or decrease the effects of Earth's atmosphere for these kind of observations?

A quick search shows that the largest optical telescope is only 10.4m, and we would probably want to put it in space, free of atmospheric distortion.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#137

Post by Steko »

baron816 wrote: post #37

Ok, let's assume we find a warm, watery planet like Earth's within ~20 light years, and we figure out a way to travel >= 50% the speed of light, making it somewhat reasonable to get there. If the planet's gravity is greater than 10% different from Earth's, or its Day/Night cycle is much different from Earth's, wouldn't it still be a nightmare to live on. Anatomically modern humans have lived on Earth for 200,000 year…

Adaptation isn't a great issue imho, the main issue is whether the 20th century sci-fi trope of colonizing space is a good idea in the first place and I'm pretty skeptical it is. These threads always strike me as incredibly naive in just assuming we would want to go anywhere/everywhere.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#138

Post by moonbug22 »

ExactoKnight wrote: post #124
moonbug22 wrote: post #106

Earlier quoted context omitted.

You know about the SKA, right?

Could the Square Kilometre Array, by measuring in the radio frequency of the electromagnetic spectrum, actually be capable of directly imaging the nearby spectroscopic signatures of exoplanets? I thought you needed to be capable of directly imaging the light of an exoplanet in other wavelengths in order to do that.

Here ya go http://skatelescope.org/cradle-life/

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#139

Post by bachaco »

lmm wrote: post #18
chrismealy wrote: post #7

The fastest spacecraft ever built would take 4000 years to travel one light year.

If we wanted it badly enough, we could get to tau Ceti with current technology. The Orion designs are sound, and could carry a population capable of sustaining itself for the 100-odd years it would take to get there.

I wouldn't mind dying of old age inside a space ship. As long as I have internet connection / computer / private room, I am all good.

Re: Four Earth-sized planets detected orbiting the nearest sun-like star

#140

Post by kuschku »

afterburner wrote: post #107
ExactoKnight wrote: post #101

I am flabbergasted that as a society we aren't rushing to build a 100 metre wide telescope mirror large enough for us to directly image the spectra of the potentially habitable exoplanets around us. A telescope this large could tell us whether any of these potentially habitable planets contain oxygen, and thus, biological processes. Yet thanks to funding cuts in science the biggest telescope we have in the pipeline r…

They did plan one (maybe you were thinking of it), but passed in favour of a 39m one: https://en.wikipedia.org/wiki/Overwhelmingly_Large_Telescope We certainly can't visit these places for quite some time though.

And the 60 or 100m OLT will likely still be built over the next decades.

ESO is not going to give up, and they don't have to fight with science-deniers for funding, so there's not much to worry about yet.

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