Hacker News new | past | comments | ask | show | jobs | submit login

At thought at first that the title was clickbait.

" You mean to tell me that we can see light from the edge of the universe, but we can't tell if an object will be bright (or not) when it arrives at earth ? "

Reading the article, it seems that there's materiel that will react with the faint but steady hit of sunrays. Still , with our tech and advancement, you'd think we would be able to give a reasonably accurate prediction of whether a a very large stone will continue to shine bright when it passes by earth at supersonic speeds.




"I have an object composed of unknown materials, jumbled together in an unknown way, with unknown density. I'm going to hold it next to a light and heat source. How bright would it be?"

That sounds like a difficult problem.


Not really. You just need good data or approximations of the data. Then just compute.


The "unknown" part implies lack of data.

We literally don't know what gases, and how much of them, will evaporate off of it until they do evaporate. And that doesn't happen until it warms up more.


We can estimate.


The current data gives estimates between "brighter than stars" and "not visible without instruments".


Yeah, let's just measure the density and composition of a comet that will be here in a few months, and with expectations that it may be releasing new gaseous formations as it gets closer, predict what will happen with those formations.

Let me just code that up real fast.


You can literally measure anything, that’s not the same as being 100% precise. That’s how it works.


The difference is compounding, unstable systems.

In much simpler form, it's similar to the "Where will this satellite in a decaying orbit land?"

The difficulty is not the approximation: the difficulty is that whether drag begins to increase at t=x or t=x+30sec (based on orientation when it first encounters atmosphere) cascades throughout the rest of the equations and dramatically changes the results.


Monte Carlo it


Are you a product manager by any chance? Because I can totally imagine you telling someone to just use some cloud DB because it's infinitely scalable.


That doesn't help if the convergence is a bi+ modal distribution, due to the underlying nature of the problem.


Elon is it you?


it's not the stone that shines, but cloud around it

and we can't even precisely predict cloud formation more than week or two in advance right in our face - on Earth

so no wonder comets are unpredictable


A big part of the question is whether it will still be offgassing enough to produce a bright coma.


It all depends on how much ice is in the comet.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: