Live data from Hacker News

Researcher links mass extinctions to 'Planet X'

phys.org

41–50 of 66 posts

Re: Researcher links mass extinctions to 'Planet X'

#41

Would it be possible to see this planet X with optical telescopes if we knew where to look at? (Assuming the figures given in article, mass 10 times earth, distance from sun 1000 times earth's distance)

In short, if we could it would already have a name.

XKCD did a great chart to explain this potential 9th planet: https://xkcd.com/1633/

Re: Researcher links mass extinctions to 'Planet X'

#42

Would it be possible to see this planet X with optical telescopes if we knew where to look at? (Assuming the figures given in article, mass 10 times earth, distance from sun 1000 times earth's distance)

If its mass is 10 times Earth but it has similar density, its diameter would be 10^1/3 times Earth's, or 2.75 x 10^7 m. 1000 AU is 1.50 x 10^14 m. Their ratio is equal to the angular size in radians, since atan(x) = x to within our desired precision, giving 2.75e7/1.5e14/2pi36060*60 = 0.0378 arcseconds.

The Keck observatory has angular resolution of 0.04 arcseconds at best, according to Wikipedia. So, by this back of the envelope calculation, the answer is "theoretically, but probably not".

Re: Researcher links mass extinctions to 'Planet X'

#43
post #32

Earlier quoted context omitted.

That's fine. We still have a thousand years or two. We should be off this planet by then.

It's weird how we seem to understand exponential growth of technology but have a hard time grasping the exponential build-up of excess greenhouse gases due to the exponential growth of human population and economy. I wonder how these thousand years might look if currently there have been temperature difference of extremes by 20 degrees, with average already raised by 2. For example, mass extinction of oceanic ecosyst…

Presuming, we don`t have some AI that bio-upgrades whole ecosystems via DNA-update. Your seahshell of 2050 might be made of carbonfibre. Still its a race..

Re: Researcher links mass extinctions to 'Planet X'

#45

Would it be possible to see this planet X with optical telescopes if we knew where to look at? (Assuming the figures given in article, mass 10 times earth, distance from sun 1000 times earth's distance)

They have been looking for Kuiper planet X on the cover of Scientic American last year. They ruled out a gas giant planet because it would have been bright enoungh in infra red from the heat of self gravitation to already have been seen.

The kuiper planet x modeling can only constraint to about a quarter of the sky, which is large search.

By Keplers Law a highly elliptical planet x orbit would spend most of its time far out when itbis dimmest and slowest. This planet x could be 40 times further away than pluto where it could a thousand times dimmer and a hundred times slower motion across thevsky than hard to see pluto.

The extinction planet x is even farther and slower.

Re: Researcher links mass extinctions to 'Planet X'

#48
post #20
post #14

Earlier quoted context omitted.

So in the end, you envision addiction destroying humanity. It's an interesting insight but I can't really see it happening the way you describe. There are already many substances (opiates, crack, meth to name a few), some that have been around for centuries, that give intense dopamine-release rushes. Yet, only a small percentage of people, around 5-10%, seem to have the addictive personality required to completely di…

We now face the danger, which in the past has been the most destructive to the humans: Success, plenty, comfort and ever-increasing leisure. No dynamic people has ever survived these dangers. - John Steinbeck [1] [1]: https://www.goodreads.com/quotes/559551-we-now-face-the-dang...

They are "dangers" only when your neighbors don't have them. When the whole world has success, plenty, comfort and ever-increasing leisure, there's little reason for anyone to become agitated and attack someone.

At least until we run into an agitated alien species with better toys than us.

Re: Researcher links mass extinctions to 'Planet X'

#49
post #25

Earlier quoted context omitted.

We're currently the primary cause of an on-going mass extinction. [1] [1] https://en.wikipedia.org/wiki/Holocene_extinction

That's fine. We still have a thousand years or two. We should be off this planet by then.

The idea that humans can colonize other planets is plausible. You send a thousand smart people to Mars with the right supplies and equipment and they could use it to build a self-sustaining infrastructure that then grows into a community of millions.

The idea that ten billion humans are going to take off in spaceships and abandon the Earth is utterly preposterous. The last human on Earth will die on Earth, not leave it for some other place.

Re: Researcher links mass extinctions to 'Planet X'

#50

Would it be possible to see this planet X with optical telescopes if we knew where to look at? (Assuming the figures given in article, mass 10 times earth, distance from sun 1000 times earth's distance)

If its mass is 10 times Earth but it has similar density, its diameter would be 10^1/3 times Earth's, or 2.75 x 10^7 m. 1000 AU is 1.50 x 10^14 m. Their ratio is equal to the angular size in radians, since atan(x) = x to within our desired precision, giving 2.75e7/1.5e14/2pi 360 60*60 = 0.0378 arcseconds. The Keck observatory has angular resolution of 0.04 arcseconds at best, according to Wikipedia. So, by this back…

In your above calculation, you're assuming that an object needs to be resolved to be visible. To the contrary, telescopes are able to see un-resolved objects (objects whose angular size is below the angular resolution of the telescope) all the time -- they are called "stars". The relevant parameter here isn't angular size, but flux[0] (brightness).

[0] https://en.wikipedia.org/wiki/Radiative_flux

Post reply on HN