I thought it was obviously a monolith.
Another pretty darned accurate rocket landing today BTW. Pretty cool that its so unfazed by the fog :D
RichVR
3050
Thought this might fit here.
“Where we’re going we don’t need eyes.”
Obviously, the denizens of Yuggoth trying to get just a little closer to Earth.
The next Falcon Heavy launch is on for tonight. They’re calling it their most difficult launch yet since it will be launching with more thrust for longer, landing its core stage further downrange (almost 800 miles), and shifting between more widly-varying orbits ending up a little shy of geostationary orbit in order to deploy 24 satellites for NASA and various agencies and companies under a US Air Force testing program.
I’m particularly looking forward to the little crowdfunded solar sail from the Planetary Society. It’s docked in a mothership which is a secondary payload on this launch which will watch it spin out a wide mylar sail from a tiny box. It’s supposed to spend months testing out how to raise an orbit up from Earth using only the momentum of solar photons.
That’s pretty cool!
Unfortunately, 11:30pm EST might be a little past my bedtime. Will have to catch it on YouTube tomorrow.
DeepT
3054
If photons are massless, then how do they “push” a solar sail?
Photons don’t have rest mass but they have momentum
And that momentum can be transferred to other bodies.
I thought every nerd had one of these as a child’s toy. No, just me?
SpaceX’s infrared tracking cameras are one of the coolest things I’ve ever seen, especially during the side boosters’ boostback burns.
That’s inherent in momentum, no? It’s kind of what it means.
It’s just important to understand that under relativity, light can do this as well.
More info for everyone else (like me) who originally only learned Newton’s version of momentum:
Editer
3061
I was watching last night’s Falcon Heavy launch live and my son stopped by my office to say goodnight.
“Hey, stick around for a second, the center core is landing. Who knows, it might blow up.”
Oooops.
At least we got to share his first live rocket explosion together.
Well yeah. I was just quoting the article. Besides, while you are certainly correct, when the object in question has no mass it “feels” counterintuitive, anyway.
In case you or your son have never seen it:
Editer
3064
Thanks, @Romalar. :) We have seen this. He was just impressed that he saw the boom live as it happened.
I’ll be interested to hear what the cause was. It looked like it was on track for a good landing from the exhaust you could see on OCISLY’s deck as it was coming in. Then it went off to the side. I’m guessing either one engine shut down or it was a commanded abort for some reason.
Matt_W
3065
Radiation pressure can be derived using classical electromagnetism. Maxwell described it in his Treatise on Electricity and Magnetism. If you consider a light wave striking a conductive mirror, you can use Ampere’s law to calculate induced currents in the mirror due to the oscillating B fields in the light wave, and then use Lorentz’s law to calculate the force due to the induced currents. Since the induced currents are in phase with the B field, they produce a net force in one direction. And since there’s a force generated, the wave must have had momentum so that it can be conserved.
Elon tweet about center core landing failure.
The launch overall was a success with all satilites deployed. A cool shot of the 27 Merlin engines powering the FH off the pad.
I never realized they had so many failures in landing. I only remember seeing one or two.
