US jet shoots down unknown object flying off Alaska coast • Hacker News Board

Re: US jet shoots down unknown object flying off Alaska coast

#801

Post by John23832 » Sat, Feb 11, 2023, 1:21 PM UTC

Stevvo wrote: post #409

John23832 wrote: post #356

Earlier quoted context omitted.

It’s not theory, it’s actually military practice. Adversaries spend 100k for a military grade drone. What do shoot it down with? A 1M dollar Patriot? Whatever you choose will be orders of magnitude more expensive than the drone. Israel’s Iron Dome has the same issue. It costs massively more for defense than attack.

Drones are constantly being shot down by ZPUs and other obsolete AA guns mounted on technicals. Costs even less than the drone you are shooting.

You cannot shoot down a drone at 40k feet with an anti aircraft gun.

Re: US jet shoots down unknown object flying off Alaska coast

#802

Post by Kon-Peki » Sat, Feb 11, 2023, 1:26 PM UTC

arrrg wrote: post #700

Kon-Peki wrote: post #690

Earlier quoted context omitted.

The funny thing about Olympic-sized swimming pools is that they are so big that they are nearly useless except for the relatively rare elite swimming competition. So they are actually far more uncommon than you might expect, and are usually built with configurable “walls” so that they can be made smaller for everyday use!

That seems like hyperbole. They are certainly not a place where you can (easily) have fun playing around in the water, nor a place for beginners to learn to swim. However, they are still exactly right for anyone who can swim and wants to do some plain swimming. The local 50 meter pool here is always filled with people young and old (and on no way elite) that just swim. You don’t need to be very fit to be able to swim…

If you are in the US, you are lucky to live near such a complex. They are not common.

The NCAA only started to “recommend” that universities, when building new facilities, to make their competition pools Olympic sized in 1996.

Remember that Olympic pools are deep - usually a minimum of 2.15 meters - and don’t usually have ledges for assisting with egress. They are really dangerous. A person that gets into distress, especially near the middle, will find it nearly impossible to self-rescue. Without attentive guards/coaches/onlookers they are nearly certain to drown.

Re: US jet shoots down unknown object flying off Alaska coast

#803

Post by d1sxeyes » Sat, Feb 11, 2023, 1:43 PM UTC

nikcub wrote: post #605

ajsnigrutin wrote: post #505

Earlier quoted context omitted.

This was supposedly done during the US bombing of yugoslavia... open microwaves transmit pulsed radiation, automatic systems think it's a radar and bomb the site.

Can confirm this and that it happen in both Bosnia and the Serbia campaigns. I had family members who were involved [0]. The deception methods that were applied were truly remarkable, they used decoy tanks and sent people out to imprint fake tank tracks into fields. They also understood IR and would shield real troops while leaving coal to burn in empty pillboxes and bunkers There was also the shoot down of the F-117…

Winning wars with air power alone is a very dangerous thing to do.

It puts success entirely in the hands of the best funded. You can simply simulate the war and arrive at the outcome.

So as a member of the “losing” side, how do you respond? You only have one choice to win: escalate. Escalate to terrorism, NBC weapons, etc.

Both sides have to bleed in a fair-ish fight to keep wars roughly conventional.

Re: US jet shoots down unknown object flying off Alaska coast

#804

Post by hanche » Sat, Feb 11, 2023, 2:06 PM UTC

cardiffspaceman wrote: post #698

13of40 wrote: post #652

Earlier quoted context omitted.

If you carry a calculator in your pocket, but if you're just casually converting, 3 feet per meter is pretty good. 100 square meters is about 1000 square feet as well. Not legal for tax purposes, but good enough to understand how big a place is.

40 inches per meter is easy to remember and pretty accurate

Or ten feet per three meters, since longer distances are rarely measured in inches anyhow.. The proverbial ten foot pole is 3048 mm long.

Re: US jet shoots down unknown object flying off Alaska coast

#805

Post by tsimionescu » Sat, Feb 11, 2023, 2:07 PM UTC

jasmer wrote: post #461

tsimionescu wrote: post #230

Earlier quoted context omitted.

Your own government has a much higher ability to affect your life than China does, so what you're saying is completely irrational. Not that it's OK for the Chinese to spy on us, mind you, or to claim that they don't have nefarious purposes.

Moral relativism between US and China is unfathomable. They are not remotely comparable on the whole. China has a Dictator, a total absence of a Justice System, total surveillance and censorship, and large swaths of the population of some regions in concentration camps, a large number of individual dedicated to holding in place that apparatus. Meanwhile you're free to walk down the street and tell the US President he…

I had no such intention, I had hoped I made that clear. China is a terrible dictatorship, and the US, for all its faults, is a democracy with a mostly working justice system.

However, in whatever state you live in, your local government is far and away the most likely to care about your habits, to want to convince you to vote against your interests, to accuse you based on flimsy evidence etc. A foreign country poses nowhere near the same risk, even if it's the worse regime in history and you live in the best.

Re: US jet shoots down unknown object flying off Alaska coast

#806

Post by hanche » Sat, Feb 11, 2023, 2:11 PM UTC

nikcub wrote: post #612

lamontcg wrote: post #541

Earlier quoted context omitted.

The foot is just a light nanosecond, it makes perfect sense.

it isn't precisely a light nanosecond either, it's about 5mm off. today the standard foot as used in the USA is ironically just defined as 0.3048 meters

And the surveyors’ foot is 500000/499999 times that. Not sure how that came to be.

Re: US jet shoots down unknown object flying off Alaska coast

#807

Post by supriyo-biswas » Sat, Feb 11, 2023, 2:20 PM UTC

XorNot wrote: post #344

billyhoffman wrote: post #216

Earlier quoted context omitted.

While RSA isn't a state-funded technology company, they did accept a $10M payment from the NSA to make their BSafe security product default to use the DUAL_EC_DRBG cryptographically secure pseudorandom number generator. Which the NSA had designed and backdoored... https://www.theverge.com/2013/12/20/5231006/nsa-paid-10-mill...

Are the primary sources on this story from the Snowden leaks available somewhere? Even the article here points to another Reuters article which isn't available any more, and I've never been able to find out which documents people were referencing about this?

https://hyperelliptic.org/tanja/vortraege/20140506.pdf contains excerpts from the original article. Also searching for “Project Bullrun” brings up various articles on the Dual EC DRBG attacks.

Re: US jet shoots down unknown object flying off Alaska coast

#808

Post by belter » Sat, Feb 11, 2023, 2:54 PM UTC

bell-cot wrote: post #722

nikcub wrote: post #605

Earlier quoted context omitted.

Can confirm this and that it happen in both Bosnia and the Serbia campaigns. I had family members who were involved [0]. The deception methods that were applied were truly remarkable, they used decoy tanks and sent people out to imprint fake tank tracks into fields. They also understood IR and would shield real troops while leaving coal to burn in empty pillboxes and bunkers There was also the shoot down of the F-117…

> Gen. Wesley Clark was a huge advocate of the doctrine that you could win wars with air power alone and never have to sacrifice ground troops - that thinking changed after '99 Delusions about winning wars with only air power are very close to a century old now. ( https://en.wikipedia.org/wiki/Bomber_Mafia ) But they seem hugely appealing to parts of human psychology - so "proved horribly wrong, yet again" doesn't do…

Gen Clark had to be reined in by the common sense and prudence of a British general.

"I'm not going to start Third World War for you," - https://www.theguardian.com/world/1999/aug/02/balkans3

"...One of Clark's most debated decisions during his SACEUR command was his attempted operation to attack Russian troops at Pristina International Airport, immediately after the end of the Kosovo War in June 1999..." "https://www.reddit.com/r/CredibleDefense/comments/6hjuss/kos..."

"Incident at Pristina Airport" - https://en.wikipedia.org/wiki/Incident_at_Pristina_airport

Re: US jet shoots down unknown object flying off Alaska coast

#809

Post by yosito » Sat, Feb 11, 2023, 3:04 PM UTC

Koshkin wrote: post #506

yosito wrote: post #435

Earlier quoted context omitted.

Americans will measure with anything except the metric system.

1/40,000,000 of the Earth’s circumference does not make sense to me, but the foot does. (As does the school bus.)

Sure, the definition of a meter may be a little bit arbitrary. But the advantage of metric for measuring distances is that the units are all factors of 10.

10 mm = 1 cm

10 cm = 1 dm

10 dm = 1 m

1000 m = 1 km

Makes math and scaling up and down a lot easier than having to remember that

12 in = 1 ft

3 ft = 1 yd

5280 ft = 1 mi

1760 yd = 1 mi

Re: US jet shoots down unknown object flying off Alaska coast

#810

Post by jakeinspace » Sat, Feb 11, 2023, 3:10 PM UTC

vkou wrote: post #389

robswc wrote: post #306

Earlier quoted context omitted.

Could they shoot down the ISS, if they wanted? Isn't that thing moving insanely fast? haha. Not a space guy but always found it interesting.

The ISS orbits at ~420 KM. Epotential = mgh = 420,000m * 9.8 m/s^2 * mass ~= 4,200,000 m^2/s^2 * mass To reach that altitude, ignoring air resistance, you'd need kinetic energy, provided by the formula: Ekinetic = (mv^2)/2 Solving for v, we get v = sqrt(8,400,000 m^2/s^2) ~= 2.900 m/s ~= Mach 9 That's the minimum muzzle velocity you need to send a projectile up into the ISS's path (Add a few more mach numbers due to…

This calculation is for a ballistic projectile without air resistance. For a missile with a rocket engine, there is no minimum velocity, but you can compute the fuel energy required for the change of altitude. Delta-v isn’t important for a sub-orbital intersection trajectory, although you’ll obviously want your interceptor missile to get there fairly quickly (which will end up being more fuel efficient than a slow climb).