Exploration - When worlds colide

Bravada Cadelanne · Feb 25, 2018

Sitting at -15.3396, -127.2196 on 2 B, with 2 C just above the horizon.

Ticked over to 13.2Mm at 16:43:43
Ticked over to 13.1Mm at 16:54:55
Ticked over to 13.0Mm at 17:06:09

Based on cores being approx 13.05 Mm apart at 17:06:09, and CMDR Klutz's calculated orbital speed difference, estimated first contact is around 19:20 IGT on Monday, with max contact around 23:55 IGT, and separation around 04:30 IGT.

Numenor1379 · Feb 25, 2018

Oh I hope that initial contact time is right. I have to head to work around 20:20 IGT.

Major Klutz · Feb 25, 2018

Current average speed, based on the new distance numbers from Bravada.
29.7Mm at 01:56:46 on 24 Feb
13.0Mm at 17:06:09 on 25 Feb
Difference of 16.7Mm in 140,963 seconds or 39.15639 hours
16.7Mm / 39.15639hrs works out to a speed of ~0.426495Mm/hr
But bear in mind that Bravada didn't take his reading from the same location that Han Zulu did.

Last time I had a 67.7 hour average speed of ~0.416983 Mm/hr
and after switching to Mm, I got a 33.8 hour average of ~0.423599 Mm/hr
So it's pretty close.

13.0Mm - 1,108Km = Surface to Surface Distance of 11.892Mm.

11.892Mm / 0.426495Mm/hr = 27.8831 hours from 17:06:09 on 25 Feb
1D 3H 52M or Monday, February 26, 2018 at 8:58:40 pm

Using my original (slowest) average speed of 0.416983 Mm/hr
11.892Mm / 0.416983 Mm/hr = 28.5191 hours from 17:06:09 on 25 Feb
1D 4H 31M or Monday, February 26, 2018 at 9:37:40 pm

Give or take a rounding error and understanding that the speed is not constant so it could be speeding up or slowing down as the time approaches.
Arrive early and prepare to stay a while ...

Numenor1379 said:
Oh I hope that initial contact time is right. I have to head to work around 20:20 IGT.

It's a window. Last time it was ~90 minutes early from my initial calculation based on 0.416983 Mm/hr and only about 15 minutes late based on 0.423599 Mm/hr
You never know since it's not always moving at the average speed.

Major Klutz · Feb 25, 2018

We may need to revise Malenfant's original calculation of 132.9 days.
The initial prediction of Oct 14 was off by ~ a day for the last collision.

Based on a distance of 29.7Mm at exactly 20:36:40 on Oct 12 2017 and a distance of 29.7Mm again at precisely 1:56:46 on Feb 24 2018 GMT.
it would be a period of ~134 days, 5 hours, 20 minutes. But the locations where the measurements were taken were not consistent.

If the current collision prediction holds true, it'll be somewhere around 133 days, 17 hours.
Give or take a few hours due to that darn speed variation.

Numenor1379 · Feb 25, 2018

I will be arriving in system on PS4 later today. Hopefully there will be no differences between platforms. Will post distances when I get them.

Macedonica · Feb 25, 2018

I've been pottering about in the local region now for a couple of days while waiting for the moons to converge. I must say that the background is a feast for the eyes with that massive gas giant hanging over the everything and a lovely scattering of nebulae framing everything.

I am powering down the Lakon Type 6E for the night now but will power up again tomorrow evening to hopefully watch and record the convergence live on youtube.

Jackie Silver · Feb 25, 2018

I'm parked up on 2C with 2B almost directly overhead. Time is 22:50. Distance to (the centre of) 2C is 1.11Mm. Distance to (the centre of) 2B is 9.29Mm.

I'm surprised to see them so close already.

(edited - corrected values due to me being silly the first time and getting the gas giant directly overhead instead of 2B!)

Major Klutz · Feb 26, 2018

Jackie Silver said:
I'm parked up on 2C with 2B almost directly overhead. Time is 22:50. Distance to (the centre of) 2C is 1.11Mm. Distance to (the centre of) 2B is 9.29Mm.

I'm surprised to see them so close already. ...

2B has a radius of 1.347Mm so I figure the surface of 2B is ~7.943Mm from where you're parked.

7.943Mm / 0.426495Mm/hr is ~18.4 hrs remaining. That puts it at ~17:14 tomorrow.
That's quite a ways off from the ~21:00 prediction, but it's probably been moving fast for most of today and will slow down it's approach speed before tomorrow.
Still, better to get there early, I may have made a mistake in my calculations.

Bravada Cadelanne · Feb 26, 2018

Ticked over to 8.08Mm at 05:41:10 from my vantage point with 2 C on the horizon. Surface to surface distance would be approx. 5.706Mm (calculated using sqrt(a^2 + b^2 - a*b*cos(C)) - the planet is about 3 degrees below the horizon, so C is 87 degrees, and b is this planet's radius (1.347Mm), then subtracting the sum of the two radii).

While I was writing this, it ticked over to 8.00Mm

Jackie Silver · Feb 26, 2018

Is there any orbital eccentricity to the moons? It just occurred to me that might be why the original calculation of the times was out - if they're in anything other than perfectly circular orbits it could make a big difference over hundreds of days.

Bravada Cadelanne · Feb 26, 2018

Jackie Silver said:
Is there any orbital eccentricity to the moons? It just occurred to me that might be why the original calculation of the times was out - if they're in anything other than perfectly circular orbits it could make a big difference over hundreds of days.

Orbital periods are 120757.554688s and 122027.515625s (~1.4 days)
Eccentricities are 0.000959 and 0.001111
Inclinations are 0.146667° and -0.073311°

Jackie Silver · Feb 26, 2018

Do we have precise S.M.A. for the moons, or precise masses for the moons and the gas giant?

Numenor1379 · Feb 26, 2018

On PS4, parked on the surface of 2B, 1.35Mm from it's center. Distance ticked to 5.69Mm at precisely 9:32:24.

5.59Mm at 9:52:59.

CMDR ANCALAGON · Feb 26, 2018

I've been putting all of the times & observed distances from this thread into a table to see how current event mirrors the previous one. The last couple of reported times and distances seem to reflect some minor variances from the last event, but these could be due to differences in where the observations were made.

Unfortunately, I do not have a lot of examples where observed distances or times from this event match what was observed in the previous event, but it seems to be generaly be hitting the same distances at the same intervals.

The two data points that are the same, in terms of measured distances are then 29.7Mm and 8.08Mm. I took all of the readings from the last event and added a column to show the duration until the next milestone (recorded distance). In the last event, the next milestone was 03:29 later at 27.8Mm. So for this event, if they were tracking the same, we would expect to see 27.8Mm on 24FEB04 05:25.

Based on this, we would have expected to see a distance of 8.08 at 26FEB 04:04 (46:39:20 after the 29.7Mm mark). It appears that we hit this same milestone 48:15:12 after the 29.7Mm mark, which is 1:35:12 longer than the last event.

However, it was 55:45 after 29.7Mm mark that we hit 6Mm last time, but this time we are a bit ahead of that time, as we are already at 5.6Mm ten minues sooner than we hit 6Mm last time.

Again, these could just be due to differences in where the observations were made. Last time at 8.08 we were roughly 20:11 to impact, and at 5.46Mm we were 09:12 from impact.

Based on posts from last event, it seems that peak impact was around 15OCT 15:30, with the beginging of the impact occuring at 15OCT 09:42.

All that to say, still tracking for peack impact around 20:30 to 20:50

Bravada Cadelanne · Feb 26, 2018

Jackie Silver said:
Do we have precise S.M.A. for the moons, or precise masses for the moons and the gas giant?

Code:

  "BodyName": "Kyloasly DA-A f69 2 b",
  "MassEM": 0.00359,
  "Radius": 1346913.0,
  "SurfaceGravity": 0.788827,
  "SemiMajorAxis": 216721152.0,
  "Eccentricity": 0.000959,
  "OrbitalInclination": 0.146667,
  "Periapsis": 269.940155,
  "OrbitalPeriod": 120757.554688,

  "BodyName": "Kyloasly DA-A f69 2 c",
  "MassEM": 0.001989,
  "Radius": 1108170.75,
  "SurfaceGravity": 0.645422,
  "SemiMajorAxis": 218237952.0,
  "Eccentricity": 0.001111,
  "OrbitalInclination": -0.073311,
  "Periapsis": 321.730164,
  "OrbitalPeriod": 122027.515625,

  "BodyName": "Kyloasly DA-A f69 2",
  "MassEM": 69.120575,
  "Radius": 54635300.0,
  "SurfaceGravity": 9.229329,

"Periapsis" in this is the Argument of Periapsis - i.e. the angle between the ascending node and the periapsis.

5.26Mm ticked over at 14:16:18 (3 deg above horizon = 5.468Mm between centres = 3.0135Mm between surfaces.

Edit: now live-streaming for the next few hours: https://www.youtube.com/watch?v=MCJBOWF5emk

MattG · Feb 26, 2018

CMDR ANCALAGON said:
Based on posts from last event, it seems that peak impact was around 15OCT 15:30, with the beginging of the impact occuring at 15OCT 09:42.

Throwing my guess into the ring, based off those times. Contact at 16:50, peak at around 22:38.

Hmm. I wonder if I can get there in time for peak...

Han Zulu · Feb 26, 2018

Getting closer now. The problem with all these measurements is that it depends on from where you're measuring (like someone said in recent post). The most accurate would be to decide a specific coordinate on each body to do it from.

3.92 Mn @ 15:38 IGT coord ( -306718, 25.6197 ) * note: I'm not in the same position as the live streams, so the measurement is probably affected

CMDR ANCALAGON · Feb 26, 2018

If these last readings are correct, then this is moving much faster than last time.

Between the two observations of 5.47Mm at 14:16 and 3.92Mm at 15:32, its moved 1.55Mm in 1:16.

From the last event, we happen to have a reported distance of 5.46Mm. The next observation of 4.10Mm was made 3:39 later, showing a movement of 1.36Mm.

So from ~5.47, it has moved a greater distance (14% more) in less than half the time (-65.3%, or 2:23 less).

I was going to head out early to make it home in time, but if this rapid acceleration continues, then I may not be able to get out that fast.

Do we think that the measurements drive moving up the impact time by a couple of hours?

Han Zulu · Feb 26, 2018

Streaming again: https://www.youtube.com/watch?v=EaT8-D4fDDQ

Major Klutz · Feb 26, 2018

Could be any time between 17:15 and 21:30. (16:24 now)
Sometimes they move faster and sometimes slower. Seems like they are moving faster now, so I'd expect an early collision.

Han Zulu, if you plan to land later, be careful. They are close enough that you can be in the sphere of influence of both moons at the same time.
Select the planet you're landing on and be ready to boost up if you start approaching the ground too fast.
For all pilots, be careful when approaching the intersection. Gravity and orientation will swap randomly depending on which moon you are closer to. However, your relative motion frame of reference will stay the same.
This can be disorienting and confusing and ships have been lost because of this. The two moons are moving at ~115M/s relative to each other.