China lands Chang'e-4 on far side of Moon • Hacker News Board

Re: China lands Chang'e-4 on far side of Moon

#241

Post by jsjohnst » Fri, Jan 04, 2019, 11:15 PM UTC

scrumbledober wrote: post #129

jsjohnst wrote: post #85

Earlier quoted context omitted.

ISS isn’t 0g, it’s actually about 0.89g. Even the moon is 0.166g. And that’s without getting super pedantic by saying there’s always some gravity anywhere you are in the universe.

ISS is in freefall though, which simulates 0G. Yes technically gravity is almost as strong as on the surface where ISS orbits, but there is no normal force opposing gravity.

Actually, the ISS isn’t in “freefall” either. Further, there definitely is a normal force (inertia) opposing gravity too, otherwise without that (and the occasional thruster burns needed due to drag from the atmosphere), it wouldn’t “continually fall and then miss the ground” as it’s normally described in layman terms.

There’s plenty of sources to back up what I said previously and here, but this provides a great description of why it’s wrong to say the ISS is in freefall:

https://www.quora.com/Is-ISS-considered-to-be-in-gravitation...

Re: China lands Chang'e-4 on far side of Moon

#242

Post by godelski » Fri, Jan 04, 2019, 11:18 PM UTC

black-tea wrote: post #224

godelski wrote: post #218

Earlier quoted context omitted.

The sun is really loud. [0] But in all seriousness, it produces a lot of radio signals. So it is completely accurate to call it loud. The moon doesn't have a magnetic core so it doesn't produce its own noise like Earth does. [0] https://youtu.be/Rvvsw21PgIk?t=17

The sun shines on the "dark side" just as much as it shines on the near side.

Well there's 28 days that it isn't shining (yes, sidreal days exist on the moon). But you also don't have Earth in view (ever). The Earth is also loud. Combine these two and you got a great place for radio astronomy.

The far side also has a lot more craters. There are also places in the poles that are always in darkness, but those aren't the best places for observatories.

Re: China lands Chang'e-4 on far side of Moon

#243

Post by avmich » Sat, Jan 05, 2019, 1:25 AM UTC

cuspycode wrote: post #198

Rebelgecko wrote: post #160

Earlier quoted context omitted.

It's currently illegal for NASA to work with China. There's been a line in the NASA appropriations bills for the last 5 years or so saying none of the money they're receiving can be used bilaterally or in cooperation with China

How about working with Taiwan? I think they too have a space program, although I have no idea how big it is.

"The 'One China' policy is not a card on the bargaining table," said Paul Haenle, a former China director at the U.S. National Security Council. "It is the table itself."

Re: China lands Chang'e-4 on far side of Moon

#244

Post by ryanqian » Sat, Jan 05, 2019, 4:11 AM UTC

valgor wrote: post #147

ForrestN wrote: post #59

[flagged]

I was really surprised to see an article on HN about China that wasn't full of ignorant hate and racism in both the article and in the comments, but then down and the very bottom is your sole lonely comment. Stay true, freedom fighter.

Good point :)

Re: China lands Chang'e-4 on far side of Moon

#245

Post by childintime » Sun, Jan 06, 2019, 1:56 PM UTC

tikumo wrote: post #62

The dark side of the moon, perhaps the perfect place for a big telescope?

I suppose the light side of the moon is also a very good place. Good enough to start with. Somewhere to the side to avoid having earth in full view.

Re: China lands Chang'e-4 on far side of Moon

#246

Post by ForrestN » Sun, Jan 06, 2019, 6:55 PM UTC

ryanqian wrote: post #244

valgor wrote: post #147

Earlier quoted context omitted.

I was really surprised to see an article on HN about China that wasn't full of ignorant hate and racism in both the article and in the comments, but then down and the very bottom is your sole lonely comment. Stay true, freedom fighter.

Good point :)

Or not :(

Re: China lands Chang'e-4 on far side of Moon

#247

Post by dhruvparamhans » Mon, Jan 07, 2019, 8:23 AM UTC

stcredzero wrote: post #161

arduanika wrote: post #5

"...and if the dam breaks open many years too soon..." Perhaps interesting to note the origin of this name for spacecraft. The legend "Chang'e flies to the moon" (嫦娥奔月) lies behind the Mid-Autumn Festival (featuring mooncakes, as it were). Point is, the names of Chinese space missions are every bit as carefully steeped in tradition as, say, Mercury/Gemini/Apollo.

The legend "Chang'e flies to the moon" (嫦娥奔月) lies behind the Mid-Autumn Festival (featuring mooncakes, as it were). Point is, the names of Chinese space missions are every bit as carefully steeped in tradition as, say, Mercury/Gemini/Apollo. The People's Republic of China doesn't think of itself as a "Nation State." Instead, it thinks of itself as a "civilization state." A part of PRC's self appointed charge is to p…

And yet we tolerate the french...

Re: China lands Chang'e-4 on far side of Moon

#248

Post by mrunkel » Mon, Jan 07, 2019, 4:39 PM UTC

stcredzero wrote: post #236

mrunkel wrote: post #226

Earlier quoted context omitted.

Well, it is actually a shame. And by that I mean why wouldn't it benefit anyone to gain access to what is probably as much writing about philosophy, history, etc. as what one is currently exposed to? You should also keep in mind that the people that are saying this to you have already learned a complete another language and alphabet (since they are presumably communicating with you in English).

Well, it is actually a shame. Asking someone to be ashamed of not having entirely elective knowledge isn't "live and let live." Nor would that strike me as being likely to be productive. Instead, you should describe how desirable and rewarding that knowledge is.

In my understanding saying "that's a shame" is equivalent to "that's really too bad," and not, "you should be ashamed of your self."

Maybe my interpretation isn't that common? (pause to google)

Apparently it is the common accepted meaning:

https://www.ldoceonline.com/dictionary/it-s-a-shame-what-a-s...