2014 MU69 "Ultima Thule" flyby, For discussion of the encounter as it happens |
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2014 MU69 "Ultima Thule" flyby, For discussion of the encounter as it happens |
 Dec 31 2018, 05:49 PM
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#61
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 Senior Member  Group: Members Posts: 1637 Joined: 5-March 05 From: Boulder, CO Member No.: 184  |
DSN Now (unofficially) indicates the downlink at 500b/sec from Goldstone.
-------------------- Steve [ my home page and planetary maps page ]
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Dec 31 2018, 06:40 PM
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#62
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 Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Fingers crossed that the latest data gives some solid indication of UT's shape and consequently its rotation state.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Dec 31 2018, 07:02 PM
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#63
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 Senior Member Group: Members Posts: 1431 Joined: 26-July 08 Member No.: 4270 |
Press conference has started.
-------------------- -- Hungry4info (Sirius_Alpha)
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Dec 31 2018, 07:23 PM
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#64
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
It's apparently indeed oblong, at least!
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Dec 31 2018, 07:24 PM
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#65
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 Senior Member Group: Members Posts: 2085 Joined: 13-February 10 From: Ontario Member No.: 5221 |
John Spencer confirms: elongated blob!
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Dec 31 2018, 07:24 PM
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#66
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Senior Member Group: Members Posts: 1431 Joined: 26-July 08 Member No.: 4270 |
Failsafe 1.
Attached thumbnail(s)
-------------------- -- Hungry4info (Sirius_Alpha)
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Dec 31 2018, 07:41 PM
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#67
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
And STILL no apparent light curve.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Dec 31 2018, 07:50 PM
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#68
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Member Group: Members Posts: 124 Joined: 20-April 05 Member No.: 291 |
Now that its shape is apparent, are there explanations left besides it tumbling so slowly that its not apparent in images?
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Dec 31 2018, 07:53 PM
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#69
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 Member Group: Members Posts: 714 Joined: 3-January 08 Member No.: 3995 |
I wonder if it could be a relatively smooth oblate ellipsoid rotating around the short axis? That could mask a rotation rate until details become resolved.
Here’s hoping for the unexpected... |
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Dec 31 2018, 07:53 PM
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#70
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Senior Member Group: Members Posts: 1637 Joined: 5-March 05 From: Boulder, CO Member No.: 184 |
Has the elongation (possible fainter lobe) rotated ~180 degrees relative to the previous image 15 hours earlier? This (together with an absent light curve) would be consistent with a rotation axis aligned with the viewing direction.
NASA TV New Horizons Q&A is to begin shortly at 2015 UTC. -------------------- Steve [ my home page and planetary maps page ]
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Dec 31 2018, 08:11 PM
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#71
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 Member Group: Members Posts: 120 Joined: 26-May 15 From: Rome - Italy Member No.: 7482 |
ok. . Binary system is excluse?
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Dec 31 2018, 08:19 PM
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#72
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
No, still possible that it is a binary. Resolution is not yet good enough to determine one way or another.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Dec 31 2018, 09:38 PM
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#73
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 Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
In the absence of any other forces, could solar radiation have halted its rotation in the orientation that presents the least "pressure"? That would indeed be a wacky possibility, but the Yarkovsky effect sounds wacky at first, too.
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Dec 31 2018, 09:47 PM
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#74
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Newbie Group: Members Posts: 17 Joined: 25-December 18 Member No.: 8512 |
Again, a completely "unofficial" indication from DSN NOW:
The download signal from New Horizons seems to have dropped at approximately 21:03UTC. Again, the indicated signal strength was fairly stable throughout at about -147 to -149 dBm. Almost simultaneously, antenna DSN26 at Goldstone began transmitting a very strong (79kW) signal directly toward MU69 and New Horizons -- presumably for the radio science experiment when that signal arrives hours later. And meanwhile, it appears that all four antennas at Canberra are all aligned and arrayed and tracking New Horizons as it climbs above the Earth's horizon. I know that DSN Now is not in any way definitive (and can be misleading), but these folks are actively involved in this endeavor. They never get to be up on the platforms at news conferences, but they are crucial. And fun to watch. |
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Dec 31 2018, 09:51 PM
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#75
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Senior Member Group: Members Posts: 2085 Joined: 13-February 10 From: Ontario Member No.: 5221 |
QUOTE (JRehling @ Dec 31 2018, 04:38 PM)  In the absence of any other forces, could solar radiation have halted its rotation in the orientation that presents the least "pressure"? That would indeed be a wacky possibility, but the Yarkovsky effect sounds wacky at first, too. That far out from the Sun, I doubt that there's any significant pressure from light, at least for a natural object. We don't know of any slow rotaters beyond the Trojans. Though given 4.5 billion years, many things are possible.... |
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