Odd rock 4.1 billion miles away

Another robot beyond the outer reaches of the solar system finds a funny-looking rock, and sends back pictures.

It zipped by at high speed and quickly gathered 50 gigabits of data, which is slowly trickling back to us — it’ll take two years to transmit the whole data set. I guess they’re still using AOL dialup out there in the Kuiper belt.

This rock is so distant and in such an empty part of interstellar space that we’ll have no reason and no opportunity to ever visit it again — so look while you can, this is probably the last time human beings will ever see it.


  1. Ed Seedhouse says

    OGH: “this is probably the last time human beings will ever see it.”

    Well, the last time we’ll “see” it in such detail. It was discovered in observations taken by ground based telescopes, admittedly as more or less as a point of light. But these observations told us it’s orbit and approximate size – otherwise we’d never have been to aim the spacecraft at ti.

    And, to be technical, if we are now “seeing” it then I have seen the Eifel tower, Mount Chomolungma and the Pyramids, though I have never left North America.

  2. nomdeplume says

    Aaaah – what a wonderful achievement by humans, in a time of climate change, war, religious fundamentalism, anti—science, the return of neo-nazis as elected leaders, refugees, extinctions.

  3. says

    I guess they’re still using AOL dialup out there in the Kuiper belt.

    I wonder, now.
    With TCP/IP, “packets in flight” takes on a new meaning. How many packets do you have in the ether at once? I imagine they are using some kind of protocol that’s designed for extremely high-latency connections. It might be doable with a carefully tuned IP stack but… (toddles off to google)

  4. Nerd of Redhead, Dances OM Trolls says

    I recall hearing the they suspected it looked like a potato. Now confirmed.

    I think our Deep Space Network could be a bit of infrastructure in need of an upgrade.

  5. Reginald Selkirk says

    I guess they’re still using AOL dialup out there in the Kuiper belt.

    New Horizons launched in 2006.

  6. whheydt says

    From what I’ve read, the peak data transmission rate is 1kb/s. And that’s actually pretty impressive considering the distance and that the transmitter output is 15W.

  7. a_ray_in_dilbert_space says

    As someone who did work on both New Horizons (Ralph and Alice instruments) and DSN, you need to keep in mind that
    1) New Horizons had to be as light as possible to make it out to Pluto before the scientists retired. Even then, it needed a gravity boost from Jupiter to get there as quickly as it did (the boost bought about 3 years, I think)
    2) The probe is very limited in power. It is so far out there that solar panels would be worse than useless. Instead, it uses a radiothermal generator to generate power, and there is only so much power one of those things can give you.
    3) Given that, the fact that DSN can even pull down 1 kbit/s from 6.6 billion km away, while attending to every other planetary and interplanetary probe, is pretty impressive.
    4) Give us money, and well build a better DSN.

  8. komarov says

    This rock is so distant and in such an empty part of interstellar space that we’ll have no reason and no opportunity to ever visit it again — so look while you can, this is probably the last time human beings will ever see it.

    I see your attitude readjustment didn’t take or last.

  9. Nerd of Redhead, Dances OM Trolls says

    ARIDS #13.

    Give us money, and well build a better DSN.

    I suspect everything that can be done with the Earthside electronics has been done. So what would really help, orbit/moon based antenna? I’m willing to pay the taxes for those.

  10. laurian says

    @ 12 is on to something.

    “It’s no use, Mr. James — it’s schmoos all the way down.”

  11. Kamaka says

    It looks a lot like 2 objects that have fused in icy space far from the sun.

    I am left to wonder, how could that happen?

    Though given a few billion years, I suppose most anything can happen.

  12. anchor says

    If volatiles like water, nitrogen, and carbon compounds like methane, CO and CO2, are considered minerals when frozen solid, then yeah, its a ‘rock’. It probably has a fair sprinkling of rocky and even metallic materials in it too. But its mostly ices. Overall density much closer to a gram per cc of (water) than that of a common rock, say, 2.65 g/c^3 of silicon dioxide (quartz). The cool stuff is the complex carbonaceous compounds preserved in the deep freeze that are the precursor ingredients of life.

    As far as the ‘trickle’ of data over 20 months, the spacecraft’s transmitter operates at 15 watts and the light-time for the signal to cover its current distance of 6.6 billion km from Earth is 6 hours and 8 minutes, where the signal strength has reduced to a billionth of a billionth of a watt. No way around that. We’re fortunate to be able to detect anything at all. A data rate of about a kilobit/second sent by a grand-piano-sized dish antenna isn’t at all bad at that tremendous range. You won’t get streaming live hifi video from any place farther than the Moon unless you’ve got a dish antenna the size of a baseball diamond gushing out megawatts. You’d need a very scary rocket to throw something like that out there as far and fast.

  13. flange says

    I think it’s dogdamned amazing. Launched in 2006, 4.1 billion miles, 9 years to get to Pluto, sending back photos? Un-manned space exploration is where it’s at.

  14. a_ray_in_dilbert_space says

    The main advantage I can see of lunar antenae is that you could build bigger ones and power the station with solar panels without worrying about weight. Of course, you’d still have to get them there.

  15. anchor says

    @23 – The composition (or the commensurate density) is inferred, not yet observationally determined, but its far more than a ‘best guess’. Its fairly well established in models of planetary formation out of interstellar molecular clouds to protostellar disks to protoplanetary condensation processes that volatiles are preserved in the outer regions of protoplanetary disks, whereas in the hotter inner portions of systems volatiles are depleted leaving a residue of refractory materials in the form of rocky and metallic objects and planets.

    But volatile dominance in the composition of many other objects in the outer system is observationally well established: fresh comets that fall in from out there are volatile-rich, the moons of the outer Solar System become progressively icy as one moves out from the Sun (or out from the host planet) and we do know that major Kuiper Belt object – namely Pluto with its system of moons – is icy.

    The starting mixture in the interstellar medium [ISM] that coalesces into molecular clouds which consists mostly of primordial hydrogen and helium, has a slight admixture of ‘metals’ dominated by volatiles in the form of molecular gas and dust grains – almost all of the latter provided by stellar nucleosynthesis long before the Solar System formed.

    This passage from a Wikipedia article on the ISM summarizes it nicely:

    “By mass, 99% of the ISM is gas in any form, and 1% is dust. Of the gas in the ISM, by number 91% of atoms are hydrogen and 8.9% are helium, with 0.1% being atoms of elements heavier than hydrogen or helium, known as “metals” in astronomical parlance. By mass this amounts to 70% hydrogen, 28% helium, and 1.5% heavier elements. The hydrogen and helium are primarily a result of primordial nucleosynthesis, while the heavier elements in the ISM are mostly a result of enrichment in the process of stellar evolution.”

    The sorted composition of surviving objects in a system reflects the processing and regional variations (like temperature and density) in protoplanetary disks during planet formation. Ultima Thule is in a near-circular orbit within the Kuiper Belt that isn’t likely to have been disturbed since its condensation 4.6 or so billion years ago, so it was most likely formed in or near that remote region from the Sun where volatiles would dominate. Hence the reasonable assumption by planetary scientists that its density should be low, reflecting an icy composition.

  16. Rob Grigjanis says

    anchor @26: I thought the picture was rather murky. Lots of ice, yes, but a huge variation in density, from less than 1g/cc (icy, porous), to nearly 3 g/cc (rocky with ice covering). And Pluto is nearly 2 g/cc.

  17. Rob Grigjanis says

    I should add that one of the reasons things are murky is that it’s difficult to determine the masses of these bodies, unless they have smaller (but detectable) bodies orbiting them.

  18. anchor says

    @Rob #27-28: Yes, of course the density question is murky. And yes they haven’t (yet) found any moons and the spacecraft flew by too far and fast to obtain a measurable gravitational deflection in the spacecraft’s trajectory that could have given a mass from which to derive a density. Nevertheless the question isn’t quite as murky as your comparison with Pluto suggests.

    Ultima is but 30 km across its longest axis running through two distinct lobes, the largest being under 20 km across along that long axis.

    Pluto is 2377 km across and has a mean density of 1.86 g/cc – which IS low, especially considering its interior materials are subjected to substantial pressure by gravitational compression.

    Ultima’s density is so far unknown, but the components can’t have been exposed to very much energy that can have driven away much of the original proportion of volatiles they acquired from the outer protoplanetary disk they assembled from. They could be significantly porous, but those round shapes of the lobes also suggest they each went pretty far to arrive at dynamic material relaxation while they were still independent bodies orbiting each other before they came into contact.

    Whether this indicates that their interiors have differentiated to produce rocky cores is a legitimate question, but it would also imply that those higher density cores – if they exist – could have migrated toward each other to the neck after the two bodies came into contact. In the low-res images so far there is no indication of any surface feature at or near the neck or anywhere else that indicates an outcropping or other surface deformation that hints at this possibility. That might change after data transmission resumes following solar conjunction and the hi-res images arrive.

    Pluto, by contrast, has endured a far more energetic history. It is large enough to have undergone substantial cryogenic volcanism and processing. The Pluto precursor (that grew to perhaps at least 3/4 of its current size) also suffered at least one catastrophic collision with another comparably-sized body that shattered it (and its impactor) to fling ejecta off the primary which subsequently became its current system of moons.

    Such an event would have created a lot of heat. It is no surprise at all that much of its original supply of volatiles could have been driven off and that it would have ended up being relatively depleted in volatile materials with a substantial rocky core. A rough estimate suggests it consists of 70% rocky materials and 30% water ice by mass. Yet Pluto is still very much less dense than any non-porous planetary object in the inner Solar System that hasn’t been imported from the outer regions as a comet.

    The variation in Ultima’s density you mention are those of estimates derived from two distinct models at opposite ends of a range of possibilities, not from non-existent measurements with error bars. Nobody doubts it contains some rocky and metallic materials. Its a matter of which model one prefers to consider – an icy chunk of rock or a rocky chunk of ice, depending on the emphasis. Or something in between.

    In any case, the likelihood that its composition is dominated by rocky materials – such as the case with objects that formed in the much warmer precincts of the asteroid belt, or with bodies like Pluto that have endured high-temperature processes and energetic impacts or collisions – is low.

    That is consistent with the fact that the precursory ingredients – from the interstellar medium, molecular cloud, and outer protosolar nebula in turn – out of which it coalesced and which has subsequently been preserved almost unaltered under frigid conditions were not dominated by rock either.