Astronomy/cosmology questions...

[Geo]

If dark matter and dark energy are negative mass fluid and the fluid is continuously created, where does it come from?

Black holes!

[Lorizael]

Here's my go to wet blanket physicist on the negative mass fluid thing:

http://backreaction.blogspot.com/2018/12/no-negative-masses-have-not.html

She is not exactly complimentary. On the "where does it come from" question, she says:

Farnes also introduces a creation term for the negative masses so he gets something akin dark energy. A creation term is basically a magic fix by which you can explain everything and anything. Once you have that, you can either go and postulate an equation of motion that is consistent with the constant creation (or whatever else you want), or you don’t, in which case you just violate energy conservation. Either way, it doesn’t explain anything. And if you are okay with introducing fancy fluids with uncommon equations of motion you may as well stick with dark energy and dark matter.

[Geo]

Every theory has to start at square one.

[Lorizael]

Right, but we're not at square one here. As she points out in her post, she and many other experts in GR have played with the idea of negative mass/energy before. The theories haven't gained much traction because problems arise when you try to reconcile them with general relativity. This guy hasn't really addressed those previously explicated problems, so there's not a great reason to take his theory seriously.

[Geo]

Oh, I don't take this theory seriously at all.
The negative repellant thing sounded to good to be true. One of my thoughts was that it could allow a sort of hyperspace travel.
Hence my black hole comment a couple posts ago, since they so to speak suck matter in.

[Buster's Uncle]

Brian May - New Horizons (Ultima Thule Mix) [Official Music Video]

[Unorthodox]

So...what the hell is up with Ultima Thule? 

I can't find much on a cursory glance, and all the news is so excited about the blurry snowman photo.  Are we still crunching data?  Are we still waiting for pics of it closer? 

You can't tell me the probe that sent back high def pics of Pluto can only manage a pixellated snowman here.  Or someone really blew the calculations and should have gotten it closer/activated the camera sooner/later/longer. 

[Lorizael]

If you'll remember, it took awhile to get high resolution images of Pluto, too. The downlink to the Deep Space Network is 500 bits/second, and it's expected to take 20 months for all the data to be transmitted. The snowman photos we've seen so far are still slightly pre-closest approach.

But this was a harder flyby than Pluto. The big constraint is that MU69 is much dimmer than Pluto (smaller, farther from the sun), so New Horizons had to get much closer to get good photos (the camera was designed for Pluto). On top of that, there's the complication that because we knew so little about the KBO going in, pinpointing its exact position for navigation was harder.

From what I've seen, though, all the telemetry and diagnostics look good and the team absolutely expects there are much higher resolution pictures in the pipeline. iirc, the best images should be 30 meters/pixel, with the object being 30 km long.

[Unorthodox]

So [poopy] reporting (or possibly just bad on the PR team).  All the reports I've seen are in past tense, acting like that was it.  I knew that couldn't possibly be right unless something was wrong/somethone screwed up.  Need to highlight much better stuff coming down the line. 

[E_T]

Yeah, they should at least mention that there is more queued up and will be seen sometime soon.

[Lorizael]

Well I'll tell you there is another press conference today on the latest batch of data, which should be composition information from a different (non-imaging) instrument.

[Unorthodox]

compare/contrast with the news releases from Ceres. 

Granted, we don't have the 'what is the spot' mystery, but it was clear from that first image we were going to be getting a stream of info for weeks. 

Here the reports are 'we flew by yesterday, here's the pic'.  No promise of further insights.  Starting to think this is bad PR more than bad reporting.  (Something NASA has occasionally had problems with)

[Lorizael]

Yeah, with Ceres, Dawn was in orbit and still pretty close to earth, so it was understood to be an ongoing investigation with periodic updates.

I will say that in this case, while two of the institutions involved with the flyby are non-governmental (APL and SwRI), NASA is one of the currently furloughed agencies. That doesn't apply to mission operations people, but it does apply to press officers. /me shrugs

[Unorthodox]

Good point, didn't think about that bit.  It does seem APL is attempting to handle most the PR stuff and look a bit out of their depth. 

I pulled up the probe design for giggles. 

So, the images we have are from LORRI(navigation camera), this is why they suck so bad.  We also have strong indications they fired up ALICE to determine the composition, but I haven't heard of any of the other pieces of equipment even firing up.  Do we know if the other suite of instruments even recorded?  RALPH is the pics the public would want to see, but is among the more energy intensive instruments on the thing, and is oriented completely differently than LORRI, so would have had to have passed to the 'right' of the LORRI images to get a shot...but Alice would also be able to record on that side.  REX, PEPSSI and SWAP could be interesting scientifically, but not so much to the general public, and I believe they might have had to choose between ALICE or PEPSSI for a flyby.   

[Lorizael]

Take a look at these two papers for details on the planned encounter with MU69.

https://arxiv.org/ftp/arxiv/papers/1806/1806.08393.pdf

https://arxiv.org/ftp/arxiv/papers/1808/1808.02118.pdf

Short answer is, yes, they were trying to use all available instruments (and the first bit of info they got post-flyby said they had collected as much data as they expected to).