4 ms·

Hmm... according to wikipedia Ceres' surface is 110 - 155 Kelvin, or a toasty -262 to -181°F. https://en.m.wikipedia.org/wiki/Ceres_(dwarf_planet) https://en.m

Hmm... according to wikipedia Ceres' surface is 110 - 155 Kelvin, or a toasty -262 to -181°F. https://en.m.wikipedia.org/wiki/Ceres_(dwarf_planet) https://en.m.wikipedia.org/wiki/Ceres_(dwarf_planet) Which makes sense, with little to no atmosphere. If that's correct I'm a little surprised this got voted up to top comment.

MPSimmons 6y ago
The comment you replied to almost definitely relied on the data in the "Geology of Ceres" wikipedia entry[1]. This is from 1991, and was strictly an estimate. The Dawn probe in 2017[2] got a better measurement, of 110K-155K. 1 - https://en.wikipedia.org/wiki/Geology_of_Ceres https://en.wikipedia.org/wiki/Geology_of_Ceres 2 - https://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_183286.pdf https://sites.nationalacademies.org/cs/groups/ssbsite/docume...
xxs 6y ago
I read that -30F, converted to C (5/9 of -62, like -35) and ughh, no way. That "planet" is too far away.
f_allwein 6y ago
in case you’re wondering: That’s between -163,15 and -118,15 °C.
- lopmotr 6y ago
  You really shouldn't put that 0.15 on the end. The numbers weren't that accurate to begin with so it gives the false impression that those digits mean something. I hope it doesn't feel like I'm picking on you but I can't help myself saying something because this is a pet peeve of mine. Rounding appropriately is taught in physics class at school but I think most people don't learn that or think it doesn't apply outside of class.
  - Sharlin 6y ago
    Not sure why you were downvoted. The concept of significant digits is pretty important.
  - zajio1am 6y ago
    Or perhaps one should not assume anything about accuracy just from the numeric presentation of the value and when the accuracy is relevant, it should be mentioned explicitly (or looked for in the original source). Numeric presentation is just too vague way to represent such complex issue as accuracy. Not rounding values after conversion has an advantage that it does not change the meaning of the claim, while rounding requires evaulating assumptions of the original claim to ensure it is done properly. Also note that rouding of intervals is different than rounding of each of its bound value separately. If the original claim is 'the value is between 110 - 155 K', then proper rounding should be -164 - -119 degC to ensure that the original inverval is inside the new interval so the meaning of the original claim (with its implicit probabilistic assumptions) still holds, just is less accurate.
    - HourglassFR 6y ago
      > Or perhaps one should not assume anything about accuracy just from the numeric presentation of the value and when the accuracy is relevant, it should be mentioned explicitly (or looked for in the original source). Numeric presentation is just too vague way to represent such complex issue as accuracy. Of course one should assume something about the acccuracy from the number of displayed digits. It's a pretty fundamental concept in physics or even engineering. You can argue that it is just a convention but then again so are numbers in the first place. When writing down a number you will have to make a choice on how many digits to write down (even if its just zeroes), so we might as well use that to convey some meaning. Yes it does not always suffice and so we can use a more elaborate notation when needed, but by default it is a useful convention. > Not rounding values after conversion has an advantage that it does not change the meaning of the claim, while rounding requires evaulating assumptions of the original claim to ensure it is done properly. In other words, don't try to understand the claim and just compute. It can make sense in some context but I don't generally think it is the right approach.
alexgmcm 6y ago
Is it possible that the conditions in the deep oceans of that world might still be amenable to life - far below the harsh surface conditions?
- astroflask 6y ago
  Yes, but the (dwarf) planet would then need some mechanism to keep the internal temperatures up, for example Europa and Enceladus have massive planets that keep their interiors warm with tidal forces, or the Pluto-Charon (practically binary) system where both bodies are very near in terms of size/mass and keep themselves warm that way. Ceres doesn't have any companion to help in that regards, but hints of cryovolcanism have been detected (emission of water vapor on several spots), so at least _some_ internal temperature is driving volcanic processes. Still, this isn't really my area and you should definitely consider what a planetary scientist has to say, should one chime in to this conversation.
Chris2048 6y ago
I can't see any ref to surface temp on Wikipedia, but this page: https://nineplanets.org/ceres/ https://nineplanets.org/ceres/ says: > Surface Temperature: -105°C but also: > the average surface temperature is about ... minus 38 degrees Celsius

MPSimmons 6y ago

The comment you replied to almost definitely relied on the data in the "Geology of Ceres" wikipedia entry[1]. This is from 1991, and was strictly an estimate. The Dawn probe in 2017[2] got a better measurement, of 110K-155K. 1 - https://en.wikipedia.org/wiki/Geology_of_Ceres https://en.wikipedia.org/wiki/Geology_of_Ceres 2 - https://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_183286.pdf https://sites.nationalacademies.org/cs/groups/ssbsite/docume...

xxs 6y ago

I read that -30F, converted to C (5/9 of -62, like -35) and ughh, no way. That "planet" is too far away.

f_allwein 6y ago

in case you’re wondering: That’s between -163,15 and -118,15 °C.

lopmotr 6y ago
You really shouldn't put that 0.15 on the end. The numbers weren't that accurate to begin with so it gives the false impression that those digits mean something. I hope it doesn't feel like I'm picking on you but I can't help myself saying something because this is a pet peeve of mine. Rounding appropriately is taught in physics class at school but I think most people don't learn that or think it doesn't apply outside of class.
- Sharlin 6y ago
  Not sure why you were downvoted. The concept of significant digits is pretty important.
- zajio1am 6y ago
  Or perhaps one should not assume anything about accuracy just from the numeric presentation of the value and when the accuracy is relevant, it should be mentioned explicitly (or looked for in the original source). Numeric presentation is just too vague way to represent such complex issue as accuracy. Not rounding values after conversion has an advantage that it does not change the meaning of the claim, while rounding requires evaulating assumptions of the original claim to ensure it is done properly. Also note that rouding of intervals is different than rounding of each of its bound value separately. If the original claim is 'the value is between 110 - 155 K', then proper rounding should be -164 - -119 degC to ensure that the original inverval is inside the new interval so the meaning of the original claim (with its implicit probabilistic assumptions) still holds, just is less accurate.
  - HourglassFR 6y ago
    > Or perhaps one should not assume anything about accuracy just from the numeric presentation of the value and when the accuracy is relevant, it should be mentioned explicitly (or looked for in the original source). Numeric presentation is just too vague way to represent such complex issue as accuracy. Of course one should assume something about the acccuracy from the number of displayed digits. It's a pretty fundamental concept in physics or even engineering. You can argue that it is just a convention but then again so are numbers in the first place. When writing down a number you will have to make a choice on how many digits to write down (even if its just zeroes), so we might as well use that to convey some meaning. Yes it does not always suffice and so we can use a more elaborate notation when needed, but by default it is a useful convention. > Not rounding values after conversion has an advantage that it does not change the meaning of the claim, while rounding requires evaulating assumptions of the original claim to ensure it is done properly. In other words, don't try to understand the claim and just compute. It can make sense in some context but I don't generally think it is the right approach.

alexgmcm 6y ago

Is it possible that the conditions in the deep oceans of that world might still be amenable to life - far below the harsh surface conditions?

astroflask 6y ago
Yes, but the (dwarf) planet would then need some mechanism to keep the internal temperatures up, for example Europa and Enceladus have massive planets that keep their interiors warm with tidal forces, or the Pluto-Charon (practically binary) system where both bodies are very near in terms of size/mass and keep themselves warm that way. Ceres doesn't have any companion to help in that regards, but hints of cryovolcanism have been detected (emission of water vapor on several spots), so at least _some_ internal temperature is driving volcanic processes. Still, this isn't really my area and you should definitely consider what a planetary scientist has to say, should one chime in to this conversation.

Chris2048 6y ago

I can't see any ref to surface temp on Wikipedia, but this page: https://nineplanets.org/ceres/ https://nineplanets.org/ceres/ says: > Surface Temperature: -105°C but also: > the average surface temperature is about ... minus 38 degrees Celsius