Ser Scot A Ellison Posted May 26, 2018 Share Posted May 26, 2018 4 hours ago, maarsen said: Venus and Uranus both rotate in a direction opposite to all the other planets. A hyperbolic orbit is a sure sign of coming from interstellar space. Any elliptical orbit, not so much. But they orbit in the same direction as other bodies. Don’t the strange rotations of Venus and Uranus indicate massive impact at some point? Link to comment Share on other sites More sharing options...
Altherion Posted May 26, 2018 Share Posted May 26, 2018 4 hours ago, maarsen said: You are right. The assumption is that conserving angular momentum requires all bodies in our solar system to have the same angular momentum as the original cloud from whence all came. Having a few large bodies not following the rules means smaller bodies not following the rules are not a sign of much. Consider also that the axial tilt of Uranus is 90 degrees, and as such is also at odds with the other planets in terms of angular momentum. I think you are confusing two different angular quantities, one centered on the axis of a given planet and one centered on the Sun (well, the center-of-mass of the Solar System, but it's pretty much the Sun). The spin of the individual planets can be affected by a variety of factors (collisions, tidal forces, etc.), but the orbital motion around the Sun needs something from outside the Solar system to mess it up. Link to comment Share on other sites More sharing options...
Jace, Extat Posted May 26, 2018 Share Posted May 26, 2018 3 minutes ago, Ser Scot A Ellison said: But they orbit in the same direction as other bodies. Don’t the strange rotations of Venus and Uranus indicate massive impact at some point? Don't play coy, Scott. Tell us more about the Deep Impact on Uranus. Link to comment Share on other sites More sharing options...
Ser Scot A Ellison Posted May 26, 2018 Share Posted May 26, 2018 7 hours ago, Pony Empress Jace said: Don't play coy, Scott. Tell us more about the Deep Impact on Uranus. So, when is your 9th birthday coming up? Link to comment Share on other sites More sharing options...
maarsen Posted May 26, 2018 Share Posted May 26, 2018 7 hours ago, Altherion said: I think you are confusing two different angular quantities, one centered on the axis of a given planet and one centered on the Sun (well, the center-of-mass of the Solar System, but it's pretty much the Sun). The spin of the individual planets can be affected by a variety of factors (collisions, tidal forces, etc.), but the orbital motion around the Sun needs something from outside the Solar system to mess it up. The total angular momentum should be the same as that of the primordial gas cloud in theory. Passing objects with a different source of angular momentum can add angular momentum into what is assumed to be a closed system. As the primordial cloud that birthed our sun probably birthed hundreds of other suns, assuming our solar system has always been a closed system is not helpful. Look at the creation of our moon. Some Mars sized planet slammed into the Earth to create the moon but where it now? It could be orbiting another sun perturbing net angular momentum calculations for astronomers in that system. Link to comment Share on other sites More sharing options...
Jace, Extat Posted May 26, 2018 Share Posted May 26, 2018 6 hours ago, Ser Scot A Ellison said: So, when is your 9th birthday coming up? Joke's on you, I'm already 10! Link to comment Share on other sites More sharing options...
SpaceChampion Posted May 26, 2018 Author Share Posted May 26, 2018 Apollo 12 astronaut Alan Bean has passed away. Link to comment Share on other sites More sharing options...
SpaceChampion Posted May 28, 2018 Author Share Posted May 28, 2018 Great twitter thread about Apollo 12, lunar dust and Alan Bean. Link to comment Share on other sites More sharing options...
Spring Bass Posted May 29, 2018 Share Posted May 29, 2018 RIP Alan Bean. Another one gone. I hope we land on the Moon again before all of the Apollo Program moon-walkers pass away, but I'm not optimistic. Link to comment Share on other sites More sharing options...
SpaceChampion Posted June 4, 2018 Author Share Posted June 4, 2018 SES-12 launch Link to comment Share on other sites More sharing options...
SpaceChampion Posted June 30, 2018 Author Share Posted June 30, 2018 Early Friday morning the CRS-15 cargo resupply mission to the space station flew successfully. This was probably the second last Block 4 Falcon 9, so from here on out it should be Block 5s, which are designed for greater reusability, until one B4 more is launched as part of the in-flight abort test for the Crew Dragon program. This Block 4 first stage has flown before in April to launch a science mission for NASA. No landing attempt, expeded. Link to comment Share on other sites More sharing options...
Free Northman Reborn Posted July 11, 2018 Share Posted July 11, 2018 So, on the fairing recovery front, Mr. Steven's net has been enlarged a tad, to try and scoop the returning fairings out of the air before they hit the water. https://www.teslarati.com/spacex-mr-steven-arm-upgrade-complete-quadruple-size-net/ Elon's response: "Well, it looked smaller on paper". https://twitter.com/elonmusk/status/1017053585157193728 Link to comment Share on other sites More sharing options...
SpaceChampion Posted July 18, 2018 Author Share Posted July 18, 2018 Just saw this going on right now... Blue Origin's launch escape test for their suborbital vehicle. Link to comment Share on other sites More sharing options...
Free Northman Reborn Posted July 19, 2018 Share Posted July 19, 2018 14 hours ago, SpaceChampion said: Just saw this going on right now... Blue Origin's launch escape test for their suborbital vehicle. Yeah, must admit. I find it hard to be impressed by their sub orbital antics in comparison to what SpaceX has achieved. I think the vast majority of people still think reaching orbit and beyond is about the altitude you can achieve, when of course altitude has nothing to do with it, it is all about velocity. In theory (if not for air resistance) you could reach orbit at a height of 1 foot above the ground, if your horizontal speed was just high enough. So Blue Origin going straight up and immediately straight down again is an order of magnitude less impressive than achieving actual orbit. I mean, it really struck home for me when they announced Max Q at something like 700 mph during yesterday’s launch. Thats barely the kind of aerodynamic stresses an airliner would endure. Link to comment Share on other sites More sharing options...
Erik of Hazelfield Posted July 19, 2018 Share Posted July 19, 2018 Seems to me they are trying to do something entirely different: affordable space tourism. Less exciting than orbital flight, yes, but they seem to be making good progress and that escape test was pretty cool. Does the SpaceX Dragon have that capability? To escape and survive a booster failure during ascent? Link to comment Share on other sites More sharing options...
Free Northman Reborn Posted July 19, 2018 Share Posted July 19, 2018 1 hour ago, Erik of Hazelfield said: Seems to me they are trying to do something entirely different: affordable space tourism. Less exciting than orbital flight, yes, but they seem to be making good progress and that escape test was pretty cool. Does the SpaceX Dragon have that capability? To escape and survive a booster failure during ascent? Yes. In fact, the Dragon is doing a launch abort test in a few months time where it will demonstrate exactly that, aborting from the booster rocket at the moment of maximum aerodynamic stress, to simulate a worst case scenario. Link to comment Share on other sites More sharing options...
Erik of Hazelfield Posted July 19, 2018 Share Posted July 19, 2018 Cool! Thanks for the info, I’ll make sure to watch that. Link to comment Share on other sites More sharing options...
Free Northman Reborn Posted July 19, 2018 Share Posted July 19, 2018 27 minutes ago, Erik of Hazelfield said: Cool! Thanks for the info, I’ll make sure to watch that. Here is the Dragon’s pad abort test, demonstrating its capbility to speed away from a dangerous event. In this case it was escaping from an exploding launchpad scenario. The same capability will apply to escape from an exploding rocket high in the atmosphere. Enjoy. Link to comment Share on other sites More sharing options...
Erik of Hazelfield Posted July 19, 2018 Share Posted July 19, 2018 Did you post the wrong video? That’s a replay of the Blue Origin Mission 9. Link to comment Share on other sites More sharing options...
Free Northman Reborn Posted July 19, 2018 Share Posted July 19, 2018 32 minutes ago, Erik of Hazelfield said: Did you post the wrong video? That’s a replay of the Blue Origin Mission 9. You sure you clicked on the right post? The one right above your last one? That's clearly a link to the SpaceX pad abort test. Link to comment Share on other sites More sharing options...
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