It would take a 100 km telescope to resolve planetary features of continental scale. Worth doing before sending a colony ship, but no substitute for exploration.
Let's estimate some numbers. Assume the ship has a 10,000 m^2 frontal area, is moving at 3x10^6 m/s and hits a 10 kg object once an hour.
(3x10^6 m/s) X (3600 s) X (10^4 m^2) -> 10^14 m^3 volume swept out by the ship in an hour
Therefor (10 kg)/(10^14 m^3) -> 10^(-13) kg/m^3 is the density of your Oort cloud
The Oort cloud is estimated to extend from 5000AU to 50000AU so let's assume a sphere of radius 50000AU.
An AU is about 7.5x10^15 m so:
50000AU -> 4x10^20 m so that sphere has a volume of about
(4/3)(3.14)(4x10^20)^3 -> 2.5x10^62 m^3
(2.5x10^62 m^3) X (10^(-13) kg/m^3) -> 2.5x10^49 kg
The mass of the Sun is about 2x10^30 kg. I don't think the Oort cloud masses 10^19 suns.
Current estimates of the mass of the could run around 3x10^25 kg. Thus the risk of hitting something large while passing through it is much closer to once every 10^24 hours than to once per hour. Not much of a risk. The average particle size would need to be on the order of 10^(-20) kg for there to be significant risk of hitting one, but stuff that small is not hard to shield against even at.01C.
There is considerably less to hit in interstellar space, but even if the density there was the same as in the Oort cloud the chance of hitting something large on the whole trip would be on the order of one in 10^18.
Most likely by filing the forms, paying the fee, and selling a product. That's the way it is usually done. I doubt anyone has grounds to contest the ownership of the mark but they might be able to contest its validity. They'd have to show that the mark was in widespread use before he registered it and therefor is generic.
> The GP was talking about establishing a *base* on the moon.
Very useful for research, especially astronomy, but not very useful as a departure point for elsewhere. Why climb out of one gravity well only to dive into another?
> one of the Lagrange points (L4 or L5) would be a very good place to establish a launch > point for the rest of the solar system
Of course it does. You accelerate halfway and decellerate the rest. Takes a bigger ship and either more acceleration or more time, but it's straightforward.
> Anyway, the Oort cloud may well be like the Alps were to Bronze Age man: impassible > except in certain locations and conditions.
That's silly. The density of the Oort cloud is very, very low. It consists mostly of kilometer-size objects seperated by tens of millions of kilometers. It does not form any sort of a barrier.
I don't see that life by age 850M is particularly improbable. There is a good chance that Earth had some sort of life by that age and photosynthesis not much later. It is not a great stretch to assume that things might have happened a bit faster elsewhere, especially if the late heavy bombardment happened earlier (or not at all).
An ecosytem compatible with Earth life, on the other hand, seems extremely unlikely (not that it would be necessary, as long as there was an oxygen atmosphere).
> Slashdot appears to lock up as an advertising banner is slow to load from its > unresponsive web site. A faster Javascript engine isn't going to fix this.
No, but blocking ads fixes it quite thoroughly (not that I see any need to enable Javascript for/. anyway).
> And any occasional star getting ripped apart by the black hole would create a burst of > radiation that would keep the vicinity of the black hole clear of gas and dust.
So the growth doesn't come to a complete and absolute halt: it just becomes imperceptibly slow.
Even a ten-billion-sun black hole probably emits more than a lollipop's worth of Hawking radiation in a hundred years. Thus fed only on one-a-century candies your black hole might actually shrink.
But that is the awful, terrifying, COMMAND LINE! Only a geek could possibly comprehend such horrific complexity! Typing two entire words! How could you ever expect any normal person to remember all of those cryptic commands?
Slashdot Mirror
> Halfway puts you in interstellar space.
I would never have guessed.
> That gives you zero sunlight...
You seriously expect to run a starship engine on sunlight?
> ...or particles to power your ion engines.
"Particles"?
It would take a 100 km telescope to resolve planetary features of continental scale. Worth doing before sending a colony ship, but no substitute for exploration.
See my comment above. Your assumptions lead to the conclusion that the Oort cloud has the mass of a galaxy.
Let's estimate some numbers. Assume the ship has a 10,000 m^2 frontal area, is moving at 3x10^6 m/s and hits a 10 kg object once an hour.
(3x10^6 m/s) X (3600 s) X (10^4 m^2) -> 10^14 m^3 volume swept out by the ship in an hour
Therefor (10 kg)/(10^14 m^3) -> 10^(-13) kg/m^3 is the density of your Oort cloud
The Oort cloud is estimated to extend from 5000AU to 50000AU so let's assume a sphere of radius 50000AU.
An AU is about 7.5x10^15 m so:
50000AU -> 4x10^20 m so that sphere has a volume of about
(4/3)(3.14)(4x10^20)^3 -> 2.5x10^62 m^3
(2.5x10^62 m^3) X (10^(-13) kg/m^3) -> 2.5x10^49 kg
The mass of the Sun is about 2x10^30 kg. I don't think the Oort cloud masses 10^19 suns.
Current estimates of the mass of the could run around 3x10^25 kg. Thus the risk of hitting something large while passing through it is much closer to once every 10^24 hours than to once per hour. Not much of a risk. The average particle size would need to be on the order of 10^(-20) kg for there to be significant risk of hitting one, but stuff that small is not hard to shield against even at .01C.
There is considerably less to hit in interstellar space, but even if the density there was the same as in the Oort cloud the chance of hitting something large on the whole trip would be on the order of one in 10^18.
Most likely by filing the forms, paying the fee, and selling a product. That's the way it is usually done. I doubt anyone has grounds to contest the ownership of the mark but they might be able to contest its validity. They'd have to show that the mark was in widespread use before he registered it and therefor is generic.
> We'll certainly do something of the kind at some point.
Unfortunately, I don't think it is at all certain that we will.
> The GP was talking about establishing a *base* on the moon.
Very useful for research, especially astronomy, but not very useful as a departure point for elsewhere. Why climb out of one gravity well only to dive into another?
> one of the Lagrange points (L4 or L5) would be a very good place to establish a launch
> point for the rest of the solar system
Yes.
> ...doesn't offer you any way to stop...
Of course it does. You accelerate halfway and decellerate the rest. Takes a bigger ship and either more acceleration or more time, but it's straightforward.
> Anyway, the Oort cloud may well be like the Alps were to Bronze Age man: impassible
> except in certain locations and conditions.
That's silly. The density of the Oort cloud is very, very low. It consists mostly of kilometer-size objects seperated by tens of millions of kilometers. It does not form any sort of a barrier.
> ...we'd get to that star in 100 years. So you're talking either a probe or at best a
> multi-generational starship.
Assuming lifespans continue to be limited by aging.
> And good luck getting data back over such distances!
That's what lasers are for.
> IMHO first step should be the moon.
Um, we've already done that. It would be interesting to go back and we should do it, but it would be nothing new.
> Plus we also have a platform for further reaches into space.
It isn't a particularly useful platform.
> Short of putting a nuclear reactor on this ship to get us there...
Yes, of course a starship would carry a nuclear reactor.
> I don't understand why not use nuclear reactors to propel us to relativistic speeds.
Mostly because we don't know how yet. We will.
> It's the only possible way to do it, unless there is a major physics breakthrough.
There are other ways (at least for the launch) such as laser rockets. Any starship will certainly carry a nuclear reactor (possibly fusion), though.
I don't see that life by age 850M is particularly improbable. There is a good chance that Earth had some sort of life by that age and photosynthesis not much later. It is not a great stretch to assume that things might have happened a bit faster elsewhere, especially if the late heavy bombardment happened earlier (or not at all).
An ecosytem compatible with Earth life, on the other hand, seems extremely unlikely (not that it would be necessary, as long as there was an oxygen atmosphere).
> Slashdot appears to lock up as an advertising banner is slow to load from its
> unresponsive web site. A faster Javascript engine isn't going to fix this.
No, but blocking ads fixes it quite thoroughly (not that I see any need to enable Javascript for /. anyway).
> ...not everything is being jitted.
And not everything ever will be, but I bet they will still eventually drop the interpreter.
Not centralized: no single point of failure. That is evidently a required feature of "middleware".
> And any occasional star getting ripped apart by the black hole would create a burst of
> radiation that would keep the vicinity of the black hole clear of gas and dust.
So the growth doesn't come to a complete and absolute halt: it just becomes imperceptibly slow.
Even a ten-billion-sun black hole probably emits more than a lollipop's worth of Hawking radiation in a hundred years. Thus fed only on one-a-century candies your black hole might actually shrink.
An electron and a positron usually react to produce two photons (never just one). Sometimes other particles such as neutrinos are produced.
n/t
Users expect to shut down the computer, plug in the new hardware, boot, and have the new hardware work. How does an md5sum help with that?
But that is the awful, terrifying, COMMAND LINE! Only a geek could possibly comprehend such horrific complexity! Typing two entire words! How could you ever expect any normal person to remember all of those cryptic commands?
What does Flashblock do that NoScript doesn't?
> They become over night best sellers, most of the time.
Yes, but do they earn enough to remain profitable after the vendor has paid her off?