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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

#271

Post by dredmorbius »

yoz-y wrote: post #270
spenczar5 wrote: post #129

Earlier quoted context omitted.

Very large telescopes can achieve great resolving power, but they run up against atmospheric turbulence, particularly in many of the spectral regions we care about for checking out exoplanets. Radio light passes right through the atmosphere for the most part, which is why you see very large radio telescopes, but they're not very practical for infrared or visible light scopes. Space-based telescopes are a better avenu…

What is the practical limit for a size and weight of an object that we can realistically put into space now? I imagine that a, for example, 10meter wide lens would be extremely heavy and can not be really split into pieces for shipping. How much smaller space telescopes are for the same performance?

The James Webb Space Telescope is an example of a segmented-mirror optical scope. The deployment video (simulation) is fascinating to watch:

https://m.youtube.com/watch?v=v6ihVeEoUdo

It has a 6.4m (21ft 4in) primary mirror. Which, from a pragmatics standpoint, answers your question.

Though I suspect mission plans could be drafted for a larger scope yet.

https://en.m.wikipedia.org/wiki/James_Webb_Space_Telescope

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

#272

Post by vidarh »

meric wrote: post #262
vidarh wrote: post #255

Earlier quoted context omitted.

From https://www.dawn.com/news/1319157 "ISLAMABAD: Eighty-four per cent of the population does not have access to safe drinking water in a country where commercial banks posted windfall profits exceeding Rs475 billion in three years, the Senate was told on Tuesday. Quoting a study, Provision of Safe Drinking Water, conducted by the Pakistan Council of Research in Water Resources (PCRWR), Minister for Science and Tech…

Ok apparently I have been served unsafe drinking water. "For Pakistan’s majority, the main source of drinking water is groundwater. The most common instrument for extracting groundwater in rural areas are the hand pump and the motor pump. Hand pumps and motor pumps together provide 61 percent of households with drinking water; in rural areas this percentage rises up to 70. " http://nation.com.pk/blogs/13-Jun-2015/pro…

Note that the point was not to criticise Pakistan - it seems like they are putting in quite an effort to modernise the systems. It's just that lot of these things look better on the surface and so are easy to underestimate the seriousness of the challenges.

E.g. if you have a well or running water, and no alternative, you use it, because no water is far worse than bad water. And most of the time chances are it'll be ok.

That makes it easy to conclude that it's probably safe even when there are flaws in the supply that can quickly render it unsafe or that makes it unsafe for sustained consumption.

E.g. arsenic leaking into the supply won't kill you from a drink here and there - arsenic is difficult to kill with, because too high concentrations makes you puke it up - but sustained ingestion of smaller doses may have severe and lasting health effect and may ultimately kill you.

(Arsenic is "interesting" in that a lot of arsenic contaminated water from pumped wells in developing countries is a result of inadequate testing in the rush of upgrading water sources from surface sources prone to bacterial contamination - as such, a lot of those pumped sources may in fact still represent an improvement, but in some cases also still represents a severe health risk)

Overall there's a great deal of progress in securing basic safe water supply. We're just not there yet. Even many developed countries regularly run into water supply issues.

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

#273

Post by rb666 »

paulrouget wrote: post #243
rb666 wrote: post #220

Earlier quoted context omitted.

What is the point of solving hunger and poverty when we are unable to solve climate change? Having more people and more people who can afford luxuries will only make that problem worse. I know it's a tough argument to swallow, but that doesn't make it less true.

What's your argument exactly? Saving more people will worsen the climate situation?

Yes, that's just facts. We thus need to do both, only saving people will be pointless, if there's no livable planet for them.

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

#274

Post by sametmax »

hueving wrote: post #128
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…

>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. This is because most of society is still struggling with day-to-day tasks like getting housing, clean water, reliable food, healthcare and dealing with physical conflicts. Even people rich enough to not be stuck in the s…

The US spent hundreds of billions to attack a country on the false pretense it got weapons of mass destructions. I'd argue that having the resources is not the problem here.

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

#275

Post by kybernetikos »

sametmax wrote: post #274
hueving wrote: post #128

Earlier quoted context omitted.

>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. This is because most of society is still struggling with day-to-day tasks like getting housing, clean water, reliable food, healthcare and dealing with physical conflicts. Even people rich enough to not be stuck in the s…

The US spent hundreds of billions to attack a country on the false pretense it got weapons of mass destructions. I'd argue that having the resources is not the problem here.

Trillions at the last count.

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

#276

Post by dredmorbius »

jamisteven wrote: post #76

I feel like something similar to this is announced every year, and nothing ever comes of it.

The ratte of discovery is accellerating rapidly.

This chart only show through 2014:

https://upload.wikimedia.org/wikipedia/commons/thumb/c/c5/Ex...

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

#277

Post by eulo__ »

gnarbarian wrote: post #29
lmm wrote: post #18

Earlier quoted context omitted.

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.

https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls... Project Orion is awesome and I am a big supporter. Unfortunately people won't stand for the thousand some odd nuclear bombs it would take to get the interplanetary version out of the atmosphere. Because it is so massive, building it in space also poses a problem unless we capture a iron meteorite and bring it back or mine/build it on the moon. Both of wh…

Couldn't we fuck up the tides if we mine the moon?

I realise it's like 4*Australia^3 in volume and mostly iron, but seems like small changes could have huge impacts.

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

#278

Post by weavie »

sametmax wrote: post #274
hueving wrote: post #128

Earlier quoted context omitted.

>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. This is because most of society is still struggling with day-to-day tasks like getting housing, clean water, reliable food, healthcare and dealing with physical conflicts. Even people rich enough to not be stuck in the s…

The US spent hundreds of billions to attack a country on the false pretense it got weapons of mass destructions. I'd argue that having the resources is not the problem here.

It is because of episodes such as this that we do have a problem with resources.

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

#279

Post by [deleted] »

sametmax wrote: post #274
hueving wrote: post #128

Earlier quoted context omitted.

>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. This is because most of society is still struggling with day-to-day tasks like getting housing, clean water, reliable food, healthcare and dealing with physical conflicts. Even people rich enough to not be stuck in the s…

The US spent hundreds of billions to attack a country on the false pretense it got weapons of mass destructions. I'd argue that having the resources is not the problem here.

[deleted]

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

#280

Post by misja111 »

deanCommie wrote: post #5

Key line to mitigate disappointment: "The outer two planets around tau Ceti are likely to be candidate habitable worlds, although a massive debris disc around the star probably reduces their habitability due to intensive bombardment by asteroids and comets."

That debris disc is obviously a Dyson Sphere.
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