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Old 2020-05-30, 23:42   #991
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Quote:
Originally Posted by Uncwilly View Post
So we had a launch today.
There was a lot of 'Murica going on. At least once I heard Murica^4.
Were the usual U-S-A chants replaced by one of T-S-LA(y) in honor of Musk's recent $700M bonus for putting the above-chanted-stock-symbol company's share price into an even higher orbit than the astronauts in today's launch?

And, what was the approximate ratio of NASA to MAGA swag in the crowd?
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Old 2020-05-31, 00:31   #992
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Quote:
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And, what was the approximate ratio of NASA to MAGA swag in the crowd?
The official webcast did not show crowds.
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Old 2020-05-31, 00:43   #993
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Quote:
Originally Posted by Uncwilly View Post
The official webcast did not show crowds.
A few good pics - none of crowds, just one of cheering beachgoers - in this Guardian piece. I like the picture of Trump: "uh, Mr. President, the launch is *that* way, behind you." Busy gauging at how many people are watching *him*, no doubt. But good PR is good PR...
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Old 2020-09-06, 11:18   #994
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Not sure if this all just pure woo, but ...

https://www.wired.com/story/mach-eff...tellar-travel/
Quote:
Woodward’s MEGA drive is different. Instead of propellant, it relies on electricity, which in space would come from solar panels or a nuclear reactor. His insight was to use a stack of piezoelectric crystals and some controversial—but he believes plausible—physics to generate thrust. The stack of crystals, which store tiny amounts of energy, vibrates tens of thousands of times per second when zapped with electric current. Some of the vibrational frequencies harmonize as they roll through the device, and when the oscillations sync up in just the right way, the small drive lurches forward.

...

In Einstein’s famous equation, E=mc2, an object’s energy, E, is equal to its mass, m, multiplied by the speed of light squared. That means if you change an object’s energy, you will also change its mass. An object’s mass is a measure of its inertia—that’s why it takes greater force to push a more massive object than a less massive one—so changing its energy will also change its inertia. And if, per Mach’s principle, inertia and gravity are one and the same, then changing an object’s energy means messing with the very fabric of spacetime. In theory, anyway.

Woodward realized that if Einstein was right and inertia really is gravity in disguise, it should be possible to detect these brief changes in an object’s mass as its energy fluctuates. If part of an object accelerated at the exact moment when it became a little heavier, it would pull the rest of the object along with it. In other words, it would create thrust without propellant.

Woodward called these temporary changes in mass “Mach effects,” and the engine that could use them a Mach-effect thruster. By combining hundreds or thousands of these drives, they could conceivably produce enough thrust to send a spaceship to the stars in less than a human lifetime. How to keep a person alive in space for decades is still an enormous question. But it is a mere footnote to the more fundamental issue of figuring out how to cross a void trillions of miles wide in any reasonable amount of time.
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Old 2020-09-06, 12:12   #995
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Quote:
Originally Posted by retina View Post
Not sure if this all just pure woo, but ...

https://www.wired.com/story/mach-eff...tellar-travel/
Another article with pictures and equations here.

It is not clear to me why this thing wouldn't violate conservation of momentum.
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Old 2020-09-06, 12:57   #996
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This one is more on the funny side.

https://twitter.com/PercyRover is a parody twitter account about the Perseverance probe. It identify as LatinX, and has a secondary account for Ginny, the helicopter that goes to mars with it. Also the account engage in political matter.
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Old 2020-09-12, 11:36   #997
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Do you dig the moon? NASA is buying..
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Old 2020-09-14, 13:10   #998
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Quote:
Originally Posted by Dr Sardonicus View Post
It is not clear to me why this thing wouldn't violate conservation of momentum.
It would also suggest that a capacitor will be heavier when charged than without charge, since the energy stored is supposedly higher. Same for an inductor and the magnetic field. And I guess also for anything at a higher temperature.
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Old 2020-09-14, 13:55   #999
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Quote:
Originally Posted by retina View Post
It would also suggest that a capacitor will be heavier when charged than without charge, since the energy stored is supposedly higher. Same for an inductor and the magnetic field. And I guess also for anything at a higher temperature.
I don't have a problem with that. Energy has mass. Of course, the energy that goes into the capacitor or into heating something has to come out of something else, and that something else will become correspondingly less massive. The equivalent mass is given by

m = E/c2,

which will be be pretty small in or near any molecular material whose atomic nuclei you want to remain intact.

What I have a problem with is a spacecraft's momentum changing ("Delta em-vee") without propellants, because it is less than clear to me what is acquiring the equal and opposite change in momentum required by conservation of momentum.
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Old 2020-09-14, 14:10   #1000
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Quote:
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Of course, the energy that goes into the capacitor or into heating something has to come out of something else, and that something else will become correspondingly less massive.
<snip>

... atomic nuclei you want to remain intact.
The article mentions solar and atomic as potential energy sources. When the thing is heavier move it left, and when it is lighter move it right. So even if energy is transferred from a battery then move the battery one way, and the cap/piezo/thing the other way. I can see how CoM is maintained there. Of course that doesn't mean it works, just that CoM looks to be fine AFAICT.
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Old 2020-09-14, 16:57   #1001
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We need to go back to look at Venus.

Phosphin, a gas associated with bacterial life ( on earth, at least) has been found in the middle layer of Venus athmosphere. https://www.nationalgeographic.com/s...phosphine-gas/
https://www.planetary.org/articles/venus-phosphine-biosignature
https://www.nature.com/articles/s41550-020-1174-4



But, as smbc said probably not alien https://www.smbc-comics.com/comic/2012-11-30 (yet)


Bepi-Colombo, the asteroïd probe, will use (two AFAIK) Venus gravity assist to come back with some sample. Maybe, it can do science on it's way back? ( well that was in the press briefing)


So no spiders life on mars but maybe microbial life on venus.

Last fiddled with by firejuggler on 2020-09-14 at 17:10
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