Force equals mass times acceleration, no? The ISD is hit by another ISD. The force is the mass of the Star Destroyer times the acceleration of the Star Destroyer.

Correct and the only source for acceleration is the engine of the hammerhead. If it use its thruster output for 10s on its own mass and achieve higher acceleration or if it transform this into a lower acceleration on the bigger mass of the star destroyer is irrelevant.

The kinetic energy is exactly the same.

Or in other words neither accelerating nor mass is relevant, because the force here is static, it is the force the thrusters of the corvette which puts out a certain amount of force per second. Apparently 10s of that is enough to break the shields and the hull of an ISD just fine.

Rogue two we see hammerheads screaming allahu akbar and taking out most of the 24,000 imperial star destroyers which explains why only so few are left for endor ^-^

1. Hammerhead collides with ISD.
2. Combined ISD-Hammerhead body accelerates from force of Hammerhead engines.
3. Combined ISD Hammerhead body collides with second ISD.

In the first step, the Hammerhead hits the ISD and they become one body. The initial kinetic energy of the combined ISD Hammerhead is equal to the Hammerhead's kinetic energy if the Star Destroyer was stationary. The kinetic energy remains the same but the mass is greatly increased so the disabled ISD moves very slowly.

However, after colliding the Hammerhead continues to apply thrust. As stated earlier, force is mass multiplied by acceleration which can be restated as acceleration is force divided by mass. The engines of the Hammerhead are now accelerating both the Star Destroyer and the Hammerhead.

What hits the second Star Destroyer is a Star Destroyer at the speed the Hammerhead accelerated it to. If that hit knocked out whatever system was keeping the Star Destroyer from falling to Scarif then it's also being accelerated downwards by Scarif.

I thought it was about the hammerhead cruiser scene.

That's what I was discussing, anyway.

The hammerhead cruiser scene is just a little cringe worthy. I am fine with that, it a little bit of giant a plothole, but hey, its star wars, it's fine. Though it adds up with all the other silly, illogical things which break universe internal consistency.

Internal consistency? The Star Destroyer they rammed was dead in the water, it wouldn't work on an operational one. It was probably taking all the backup power it had not to fall out of orbit.

There may be a real physics argument against it but internally it seemed okay.

And it did work on the second one too. Remember, both star destroyers explode from the kinetic force of a single hammerhead corvette giving them a nudge.

Remember, Force = mass * acceleration. When the disabled ISD started moving, it was suddenly a lot more mass...

EDIT: ninja'd

The force is actually less important in this case than the kinetic energy imparted which is equal to the mass of the projectile x velocity ² .

What this means in practice is that as long as the Hammerhead had enough to build up speed, the collision between the 2 ISDs should have been suitably spectacular, especially as one of them was unshielded. We don't know exactly how effective particle shielding is in SW since asteroids seem to make quite a mess when they hit the ISDs in ESB.

I'm just pleased they didn't mess up the ISDs and gave them all the correct structures between the shields domes. Found myself looking at them every time.

Something that's gone almost completely unnoticed I think: the GONK that showed up in thew Yavin hangar.

Rebel GONK crew, anyone?

I'm just pleased they didn't mess up the ISDs and gave them all the correct structures between the shields domes. Found myself looking at them every time.

I was focusing more on the domes themselves (and the turrets) than the targeting array - but it does make for a more ANH-ish feel. The fact that every officer other than Tarkin & Krennic, as far as I could tell, had single-row rank badges, also helped with that.

I kinda wish fractalsponge had an ISD-I style dome that he could put on some of his ships - the ISD-II style dome really shouldn't be on Victory-class vessels.

K-2SO nearly stole the show for me, even though at times he was verging on being Sheldon Cooper in space.

Haven't read the whole thread...

But one thing I really enjoyed about Rogue One was how it was less epic than the other movies, which made it more personal and was more human. I like Jedi, but I'm glad that they weren't really part of this movie, which made the troops much more important.

That said I truly loved Chirrut Imwe who I dubbed the Kung Fu Jedi. Not only did he kick butt, he was a truly cool character.

I also was quite pleased to see the Empire seem actually competent in this movie, I thought they did a great job of showing them as a force that is somewhat slow to get into motion but when they do they're pretty much unstoppable.

Also Vader rocked, between the end with him boarding the ship and the "Don't choke on your aspirations" they really nailed the true Dark Lord of the Sith.

I'm just pleased they didn't mess up the ISDs and gave them all the correct structures between the shields domes. Found myself looking at them every time.

I was focusing more on the domes themselves (and the turrets) than the targeting array - but it does make for a more ANH-ish feel. The fact that every officer other than Tarkin & Krennic, as far as I could tell, had single-row rank badges, also helped with that.

I kinda wish fractalsponge had an ISD-I style dome that he could put on some of his ships - the ISD-II style dome really shouldn't be on Victory-class vessels.

The targeting array is the only part I can point out as different. It's my only identifier so I'm glad it was right.

The mystery of Heff Tobber solved:

@pablohidalgo Hi sir. Was there a quick shot of Biggs and his mustache in the dogfight above Scarif?

@TheBrandonc Nope. You might be thinking of Heff Tobber, a Blue Squadron pilot.

https://twitter.com/pablohidalgo/status/809904220761690117?ref_src=twsrc%5Etfw

So out of curiosity, which characters deaths did you find the most moving? For me, it's a tie between K-2SO and Chirrut:

K-2SO: I grew fond of him very quickly; I liked this sense of humor and all. If he was played in a role playing game, he'd be that player that always rolled a horrible critical failure when making a bluff check. His death was predictable, but still made me sad, especially considering how many hits he took and how the odds were against him in the end.

Chirrut: his death caught me by surprise since I expected him to die in some grandiose fight. When he was walking down that line, I kept expecting him to whip out a lightsaber from that staff. The moment between Baze and him was touching. I have no idea what their backstory is, but to me, it felt like a big brother / little brother kind of relationship. The fact that Chirrut seemed "happy" that he had succeeded made it even sadder.

Chirrut and Baze both, for me. The rest of the deaths didn't have as much impacts as those, for a range of reasons, not least because to some extent they were just along for the ride, rather than having joined in on purpose per se. Plus both really well acted. K-2SO was also really sad.

All of them lol but K2 and Chirrut for me. Although Cassian's line to Jyn saying "your father would have been proud' hit me hard.

Saw the film yesterday. Conflicting plans kept me away until then and, actually, I ended up seeing it about a week sooner than I thought I'd be able.

This is a long thread, so I'll just add that I loved the film. My son, 7, immediately ranked it as not only his favorite Star Wars film but the best of any film he's ever seen. A quick couple of takeaways:

- We went home and immediately watched ANH and it changed that movie drastically for me, and for the better.

- I very much noticed the CGI on Tarkin and Leia. I knew Tarkin was in the film, so I was watching for the CGI anyway. Didn't know Leia was in the film - suspected - but still very noticeable. CGI has come a long way, but not quite there yet. Still, I don't think my son cared one lick.

- I'm thrilled that the first Star Wars spinoff is looking like a great success. Makes me hope for the Solo movie but also that Disney will see there is an audience for these stand alone films. I believe, however, that the true test will come if they decide to make non-human characters lead roles. It's fine and dandy to have a droid here and there or Chewbacca moan and groan, but I think there is still some Jar Jar trauma in both the audience and the studio. Will an audience really show up to see a bunch of Bothans? There are obviously a million stories to be told for non-human characters, but I think those stories will be left for animated shows and novels, not for the silver screen.

- My biggest takeaway, by far, is an incredible sense of sadness. Jyn, Cassian, K-2SO, etc., were all great characters. In the span of one movie (I haven't read Catalyst yet) I really invested a lot in them as characters. To know that they will not be in any more movies (I hope - please don't patch this up with a ham-fisted Rogue 0.5) is sad. I've gotten so used to knowing that Luke, Han (well, not anymore - which is good!), Leia, etc., will always show up that when good characters, that can carry whole movies on their own, die at the end it is unexpected and sad for me. But that is a good thing. I feel it is essential to good film making - emotional investment - and I think it really makes this movie better than it would have been if they all just lived happily ever after in some part of the Star Wars universe that mysteriously never showed up again in any of the films. So kudos to the writers and film makers for going there.

Actually the one that got me wasn't heroic at all..

Bodhi Rook has already had his moment of glory when random stormtrooper does a 'room clear' on the shuttle on his way past. It's so casually done by the Stormie. Poor Bodhi!

K2S0 got the 'best' death scene though.

Something that's gone almost completely unnoticed I think: the GONK that showed up in thew Yavin hangar.

Rebel GONK crew, anyone?

GONK is a common power droid, pretty sure there's one in every film. No thematic reason for this card to be Scum Only; never was, never will be. The game mechanic reason Imperials can't have it: Decimator.

Actually the one that got me wasn't heroic at all..

Bodhi Rook has already had his moment of glory when random stormtrooper does a 'room clear' on the shuttle on his way past. It's so casually done by the Stormie. Poor Bodhi!

This.

He risks his life to bring a message to rebels that he's never met, then gets tortured by them for it. He continues to risk his life helping some more rebels that he barely knows, doing the right thing. I started to think he might survive, then boom, dead. Poor Bodhi.

Something that's gone almost completely unnoticed I think: the GONK that showed up in thew Yavin hangar.

Rebel GONK crew, anyone?

GONK is a common power droid, pretty sure there's one in every film. No thematic reason for this card to be Scum Only; never was, never will be. The game mechanic reason Imperials can't have it: Decimator.

No reason that the Rebels and Imperials can't get their own GONKs though (with different abilities).

And I doubt that they needed any energy to stay in orbit, it seemed like a rather stable geostationary orbit.

Or shooting the guns requires another action to counter the reaction of the guns recoil. Or the mass lost when they launch fighters, or when they take hits or one of the other million things that can cause orbital decay. Physics are hard and in a universe with "interial dampeners" saying something isn't reacting real enough in space is the ultimate nitpick.

And I doubt that they needed any energy to stay in orbit, it seemed like a rather stable geostationary orbit.

Reminder: any action with a geostationary orbit will cause the object to fall out of orbit. Pushing it towards a planet, for example..

Or shooting the guns requires another action to counter the reaction of the guns recoil. Or the mass lost when they launch fighters, or when they take hits or one of the other million things that can cause orbital decay. Physics are hard and in a universe with "interial dampeners" saying something isn't reacting real enough in space is the ultimate nitpick.

Kerbal Space Program player here... actually, high orbits like gesynch are difficult to deorbit. However, any nudge ruins the special geo-synchonisity of that orbit, which can have effects relative to the planet in proportion to the size of the push.

This looks very close to me:

What little I've seen of geostationary orbit photography makes it look like you can get the whole planet in a reasonably good shot.

And I doubt that they needed any energy to stay in orbit, it seemed like a rather stable geostationary orbit.

Reminder: any action with a geostationary orbit will cause the object to fall out of orbit. Pushing it towards a planet, for example..

Or shooting the guns requires another action to counter the reaction of the guns recoil. Or the mass lost when they launch fighters, or when they take hits or one of the other million things that can cause orbital decay. Physics are hard and in a universe with "interial dampeners" saying something isn't reacting real enough in space is the ultimate nitpick.

Kerbal Space Program player here... actually, high orbits like gesynch are difficult to deorbit. However, any nudge ruins the special geo-synchonisity of that orbit, which can have effects relative to the planet in proportion to the size of the push.

I thought it was about the hammerhead cruiser scene.

That's what I was discussing, anyway.

The hammerhead cruiser scene is just a little cringe worthy. I am fine with that, it a little bit of giant a plothole, but hey, its star wars, it's fine. Though it adds up with all the other silly, illogical things which break universe internal consistency.

Internal consistency? The Star Destroyer they rammed was dead in the water, it wouldn't work on an operational one. It was probably taking all the backup power it had not to fall out of orbit.

There may be a real physics argument against it but internally it seemed okay.

And it did work on the second one too. Remember, both star destroyers explode from the kinetic force of a single hammerhead corvette giving them a nudge.

Remember, Force = mass * acceleration. When the disabled ISD started moving, it was suddenly a lot more mass...

EDIT: ninja'd

mmhmm, mmhmm, if I'm reading all of this correctly, the Hammerhead used the Force to push the ISD into the shield gate.

"That's how the Force works!" -Han Solo

This looks very close to me:

What little I've seen of geostationary orbit photography makes it look like you can get the whole planet in a reasonably good shot.

You are correct. Geosynchronous orbit on Earth is at an altitude of about 36,000 km. Skariff has earth-like Gravity so the altitude should be about the same. The battle takes place much closer to the planet (hard to judge exactly but looks to be just a bit above the atmosphere so probably a few hundred km.

The Gate is obviously stationary above the facility and the Star Destroyers are keeping station next to the gate so the whole lot is in powered geosynchronous orbit. Whether this is done with repulsors or engines is not clear (I would guess engines since the SDs engines are glowing which implies thrust). Any loss of power would cause them to start to fall out of orbit (which is more or less what we see).

Unless of course Skariff has a very rapid rotation and a day of ~90 minutes but there is no indication from the film if that is the case.

A point on the C-3P0 & R2-D2 scene: For me it was a neat addition, but it made my girlfriend (a fair Star Wars fan) squee with happiness. So while it detracted zero from anything (5 seconds, if that, showing a random conversation), it certainly improved the film for at least one person.

For the Hammerhead/ISD thing - that worked for me. Star Wars space physics have always been odd, but the notion that a small ship can slowly accelerate a bigger ship is fair enough, and the notion that when said bigger ship solidly rams another big ship, bad stuff happens, works fine. It wasn't a glancing blow, but a solid impact, and they both took some damage before impacting the shield and really getting mashed. (PS: F=ma, KE=0.5MV^2).

Saddest deaths: They were all sad, which is part of the brilliance. K2's was lingering and sad. Chirrut's was a massive shock after his success. Baze was 'he has found the light, and now it's gone'. Bodhi was so casual and shocking. And Jyn & Cassian had their moment of success, knowing they were dying after achieving their goal, so a poignant moment. The fact that every single death hit me was one of the really great things, there was never an 'oh well, another one gone' moment that you sometimes get.

You are correct. Geosynchronous orbit on Earth is at an altitude of about 36,000 km. Skariff has earth-like Gravity so the altitude should be about the same.

The planet itself is smaller than Earth - but not by much.

http://starwars.wikia.com/wiki/Scarif