It should be noted that the City of London is a tiny part of London, like a square mile. Its the financial district, the Wall Street of London.

It isn't suprising they are taking a pro big business stance.

The EPA guidelines are in line with the level of risk: very, very little. If you want to cut your mercury exposure, don't stop using CFLs, stop eating seafood.

As for the Bridges case, you should read the Maine EPA's account. CFLs were new back then, and they had decided to use her case to learn more about what sort of advice they should give for dealing with broken bulbs. So they sent someone with a meter because they wanted to learn more, not because that's standard practice. The carpet was already intended for removal as part of a rennovation. They took readings all over the room. The only place with "high" levels was right where the bulb broke - not in the ambient air, not anywhere else on the carpet, not on the toys, not even under the carpet where it broke. I say "high" because even the levels right where it broke weren't actually high, just over Maine's long-term exposure guidelines (which is obviously not applicable to a temporary event). Moving the meter even six to eight inches away rom the breakage point dropped the levels way down. She was told that the bulb breakage was "of negligible health concern". However "the homeowner expressed particular nervousness about exposures to mercury even in low numbers", so they told her what she could do if it bothered her, one of which was calling a cleanup contractor. And of course any private cleanup contractor will charge you an utter fortune. The Maine EPA came back two days later after the story hit the news, before anything had been done in the house. The area where the bulb broke had dropped down below Maine's limit.

The case was ridiculously blown out of proportion.

Who said I disagreed with them?

You are the one who keeps complaining about me addressing them. If you disagree with them then you should not have posted them.

Not that readers need it pointed out, but Mars has mysteriously entered the discussion.

There is no "mysteriously" about it. The distance you started quoting is less than the distance from the Earth to Mars.

In other words, interplanetary.

Interplanetary != Interstellar

Argh. You're comparing an exhaust, which rapidly cools off in space and generally acts very differently to a laser, to a laser.

No. I'm comparing the dispersal. You are arguing that the exhaust would not disperse.

In other words, you are arguing that the exhaust is focused BETTER than a laser.

And the heat has to go somewhere. It's one of the laws of physics.

You keep using that word. It does not mean what you think it means.

Yes it does. The heat of the exhaust does not vanish. Reaction mass does not vanish. Ships need a force to move them.

Physics.

I seriously have no idea where you're getting this stuff.

That you do not understand the distances involved.

In order for the ship to be hidden, it cannot be silhouetted against its own exhaust. Which means that the exhaust cannot cross the edge of the shield before it has cooled to background radiation. But the ship has to travel (at best) 100's of millions of kilometers (Earth to Mars) while the exhaust only has to travel 10 kilometers (at most) laterally before cooling.

In other words, your example ship would be a dark, shielded spot in the middle of a glowing cloud of its own exhaust. It would look like a bullseye.

It's the laws of physics.

If you're going to bring that up, please remember that the above observation is completely irrelevant ...

You were the one who brought up the Voyager craft as an example.

If you want to make the ships that difficult to detect then you are going to be travelling that slow. 300 years to reach the Oort cloud. It's the laws of physics.

"Probably very hot" is considerable fail right there.

In your opinion. The point being that it is hot enough to be detected. Now you can argue whether it is or is not but I'd once again refer you to physics.

Further, the "shielding" that everyone talks about just isn't that heavy.

So far I haven't seen anyone posting what that "shielding" is made of.

But it does not matter except that more shielding requires bigger engines.

The reason it does not matter is that the exhaust will, eventually, travel further to the side than the shielding can shield. Then it will be seen as a glowing cloud behind the shielded ship.

The whole concept of shielding for stealth revolves around the exhaust NOT being able to travel X distance to the side before cooling to background temps BEFORE the ship travels Y distance forward.

Given that X is usually measured in, at most, 10's of kilometers while Y is measured in THOUSANDS OF MILLIONS of kilometers I think that the math should be self explanatory.

But, just in case, it means that the exhaust would have to travel laterally at a rate that is less than 1/100,000,000,000 the speed of the ship.

There were two sentences out of dozens in that post that I actually wrote.

They are a direct quote from you. If you disagree with them then you should not have posted them.

It's like the terracotta army, except straw men.

You are disagreeing that a ship needs reaction mass? So you are postulating a reactionless drive.

So what you're saying is that from a million plus kilometers away, a ship with a forward profile of maybe a few score meters ...

The distance from the Earth to Mars is about 200 million kilometers.

Your example ship would be closer than Mars is. A lot closer.

... with a several kilometer wide umbrella to disguise the exhaust bits that weren't sufficiently collimated before they cool off and become indistinguishable from the background noise, especially at those distances, this ship will stand out like a sore thumb?

There is a reflector on the Moon. People aim lasers at that reflector. Those lasers diffuse over distance. "At the Moon's surface, the beam is about 6.5 kilometers (four miles) wide ..."
https://en.wikipedia.org/wiki/Lunar_Laser_Ranging_experiment
That's from the Earth to the Moon. So even if you could focus the reaction mass a tightly as a laser it would spread out over a lot more than "a several kilometer wide umbrella" would cover even if you were only as far away as Mars.

Your example ship would be a dark shielded spot in a glowing cloud of its own exhaust.

It would look like a bullseye.

Our equipment can't even pick up large asteroids before they're a few days away.

Yes it can. It does that all the time. You are confusing spotting them with projecting their course over time.

No, as another poster memorably put it ...

Quoting someone else who is not disproving it is not the same as disproving it.

It is physics. Unless you want to argue that the laws of physics do not apply ...

It doesn't magically shine through the ship like a lighthouse.

No one said it did. I've been saying that it forms a cloud behind the ship. And that cloud glows.

Nope. I'm claiming it can be hidden across much shorter distances under circumstances which are broad enough to be tactically useful.

Unless you're talking about being closer than Mars ... how did it get closer to Mars without being detected?

Yes, that heat the article that you steadfastly refuse to address, addresses.

Saying that the answer is somewhere else is not addressing my point. Quote it. Like I quoted the Wikipedia article on how much the lasers diffuse between the Earth and the Moon.

You're not a humanities guy by any chance?

Just someone with a background in physics.

I mean do you have any clue how small of a profile we're talking about here at these kinds of distances?

You are now talking about a distance less than the distance between the Earth and Mars. So something blocking out part of Mars would be very noticeable. Not to mention the Sun would be reflecting off of it. And that's not even addressing the interplanetary material that you had previously discounted.

Interplanetary != interstellar.

kilometers 350,000 is about Earth to the Moon
kilometers 200,000,000 is about Earth to Mars
kilometers 39,900,000,000,000 is about Earth to Alpha Centauri

There is no stealth in space.

So he can hit 6 out of 10.

Wouldn't random chance give him 5 out of 10?

And that's not even factoring in whether his comments are correct. And most people do NOT give accurate reports of their own winning/losing patterns.

And his self-reported "strategy" is to buy what other people are buying and to sell when they sell.

So who is selling when he is buying? Wouldn't he constantly be behind the curve? Paying too much for the stock and selling for too little?

No, you're deliberately and obviously ignoring the article.

That was a direct quote from your post. You posted it.

Actually the problem is you putting words in my mouth and then arguing with those words.

Are you going to stick to the facts as they are understood today? In order for a ship to move it needs reaction mass.

The vast majority of the exhaust will be hidden by the ship only as long as it approaches a lone target dead on. The umbrella just gives a few degrees more leeway which decreases the closer you get to your target.

And "vast majority" does not equal "stealth". You'd still show up as a glowing cloud of exhaust. That's the point.

You are aware that insulators and light blockers don't need to increase in mass proportional to the source being blocked right?

You were arguing about making them bigger. They DO increase in mass proportional to their size being increased. Make it twice as big and it weighs at least twice as much.

Not to mention that it doesn't need to be perfect, just good enough to beat the enemy's likewise imperfect sensors long enough to get close enough to strike.

Again, you'd show up as a glowing cloud of your own exhaust with a dark spot in the middle. To the defender it would look like a bullseye.

Dull radiation is as good as no radiation if the enemy can't tell the difference, and don't forget about the distances under discussion here.

That's a pretty huge caveat there. Why would the hypothetical defenders be LESS capable than we are today? Our equipment has (possibly) detected background radiation from The Big Bang.

So a new source would have to be less visible than that.

And off we wander down the garden path again.

Reaction mass goes out the back of the ship so that the ship can move forward. That's a fairly fundamental concept. And it is what you are arguing for hiding. Unless you are postulating a reactionless drive. Which is, again, its own error.

Just don't end up like a creationist or a feminist clinging fiercely to disproven articles of faith.

It is physics.

Reaction mass comes out the back of the ship.
You claim that it can be hidden across interstellar distances using a shield.
Along with all the other heat produced by the ship.

I say that you are wrong and that, in your example, the ship would be appear as a shielded dark spot in a glowing cloud of its own exhaust and that it would eclipse other objects behind it. Making it very easy to track.

"Further proving that the Stock Market is almost entirely disconnected from the underlying companies."

Exactly. I've been wondering for some time just what IS stock price based on? Since it's not based on the soundness of the company (the company doesn't even need to have a P/E!) it seems entirely based on perceived potential of the company and whatever news makes the traders nervous or ecstatic that day.

Therefore, it seems to me you're better off avoiding fundamentals and instead watching the news and reading sociology books. Oh yeah, and developing ways to do high volume trading one millionth of a second faster than you competitor.

That latter bit wasn't part of the article, it was just my own addition.

I'm replying to your post.

Even without shielding you can't see the exhaust through the rest of the ship.

And that is the problem. You take that and assume that:
a. the exhaust will always be hidden by the ship
b. shields can be put on the ship to hide the exhaust

The umbrella could be many kilometers across and of a lightweight material.

Lightweight is not the same as no-weight. Which gets back to the increase engines to support shields requiring more engines requiring more shields repeat.

Space is notoriously empty of those, hence the name.

While space is mostly empty space your reaction mass is not. Otherwise it would not be reaction mass. And you'd have postulated a reactionless drive. Which is a completely different error.

What heat beam, you've lost me. I'm talking about the ship's exhaust.

Ships have heat. Life support and engines if nothing else. This is NOT the same as reaction mass. You have to get rid of that heat AND the exhaust AND the heat of the exhaust.

With your proposal you'd show up as a glow of your own expanding exhaust cloud with a large dark shield in the center that eclipsed the stars/galaxies/nebula behind you.

And the linked article you refer to doesn't understand the idea of directed power.

That would be the part where they discussed whether shielding your engines would be possible. So, yeah, they do.

When engines aren't pointed at you, they have a much lower energy signature and aren't detectable all the way out to Alpha Centauri (though obviously a torchship is going to be pretty easy to detect just the same).

I think that you are incorrectly conflating those two statements. The engines give off reaction mass to move the ship forward. That reaction mass is probably very hot. Which means that it will radiate heat which will be seen.

Unless you are proposing some kind of reactionless drive. Which would probably violate Newton's Third Law of Motion.

And if you are going to use the Voyager craft as examples, please remember that it took 12 years to reach Neptune and will take THREE HUNDRED YEARS to reach the Oort cloud.

And of course the engines can only be noticed if they're pointed vaguely in the direction of observers, otherwise the whole exterior hull would be the same temperature as the exhaust. It could be shielded reasonably well, even if you're stuck with elderly chemical engines.

The first problem with that is that it means you have to increase your engines to support the mass of the additional shielding.

Which means more engine heat that needs to be shielded.

Which means more heat shields.

Repeat.

The second problem with that is that the beam of heat "behind" you will still radiate in all directions if it comes in contact with any object behind you. And the beam will lose focus over distance. Which means that it will have more area in which to hit objects. While the energy will be weaker it should still allow your ship to be seen in profile.

And the most common object for the heat beam to hit would be your engine's reaction mass. That is, the stuff that your ship shoots out the back in order for it to go forward.

https://en.wikipedia.org/wiki/Inverse-square_law
Energy weapons in space all have the same problem. The distances involved mean that they get real weak real fast.

At best they'd be useful in a fixed-site-defense scenario. Such as putting them on moons to defend against incoming ships.

But then you have the problem where your defeneses are not manoeuvrable. So asteroid bombardment becomes an option.

Missiles travel very, Very, VERY slow (in space). Even if they are under constant acceleration.

Lasers travel very, Very, VERY fast. But they lose energy/focus over space-type distances.

So it comes down to how well the writer understands economics and what technological advances they are postulating.

Not to mention WHY there is a war in the first place if both sides have that kind of technology available to them.

http://www.projectrho.com/public_html/rocket/spacewardetect.php#id--There_Ain't_No_Stealth_In_Space
Project Rho explains that in detail.

If you cannot move faster-than-light then your engines will give you away every time.

No, only iPhones are like that. I don't know a single Android phone that doesn't have a replacable battery. And most phones are not from Apple.