Starship Asterisk*

Dad is watching wrote:Any ideas on the surface temperatures? Similar to what is seen on the moon?

Chris Peterson wrote:

Dad is watching wrote:Any ideas on the surface temperatures? Similar to what is seen on the moon?

It is about -70°C - much colder than the sunlit Moon, but warmer than an icy body ought to be at 1.3 AU, probably because of rocks and dust on top of the surface ice.

Dad is watching wrote:

Chris Peterson wrote:

Dad is watching wrote:Any ideas on the surface temperatures? Similar to what is seen on the moon?

It is about -70°C - much colder than the sunlit Moon, but warmer than an icy body ought to be at 1.3 AU, probably because of rocks and dust on top of the surface ice.

Assuming that the dark side of the BBQ role is very much colder, and the possibility of reflected light and heat on the sun-ward side is minimal, there is little or no chance for the landers batteries to warm up enough (even at closest approach) to improve their electrical efficiency? It would have made more sense (in hind sight) to go with a nuclear power plant, wouldn't it?

Aristaeus wrote::? Did dust from the nucleus of periodic comet Swift-Tuttle actually fall to the earth or only into Earth's atmosphere?

ta152h0 wrote:that activity should dislodge Phylae ?

captainwiggins48 wrote:The photo is overexposed so details are lost. Can they even reduce the aperture of Rosetta's camera lens? Remembering the extreme brilliance of Comet West (1975-76) whose nucleus was clearly visible in broad daylight, this should have been anticipated. Something other than mere reflected sunlight must be at play here.

Ann wrote:In the Recent Submissions forum, there is an image of Comet 67P by Damian Peach. Interestingly, even though some background stars are clearly colored, the comet itself is pure white.

Does that mean that the comet has a dust tail but not a gas tail, and that it lacks a coma?

Guest wrote:I would read the explanations for the photographs if the first sentence was a simple explanation without scientific terms.

I don't read any of the explanations.

hoohaw wrote:Much as I love APOD, the caption writer is not a newpaperPerson: who, when, when, where, why, ALL in the first sentence or two. Instead, usually we have to wait until the end of the lengthy caption before we are told what we are seeing. Not good writing; sorry! (I do love APOD).

John644 wrote:I am curious to the question, if anyone has considered, using a comet, such as this one, as a vehicle to deliver deep space probes for exploration?

Chris Peterson wrote:

John644 wrote:
I am curious to the question, if anyone has considered, using a comet, such as this one, as a vehicle to deliver deep space probes for exploration?

It's an interesting idea. But keep in mind that the challenge of getting from the Earth to another place in the Solar System isn't the distance traveled, but the energy required to match an orbit. The more eccentric a comet's orbit, the greater differential velocity it will exhibit with respect to Earth while it is at Earth's distance from the Sun. So the sort of body that would be desirable to use as a vehicle is also the sort that will be hard to land on while it is near the Earth.

https://en.wikipedia.org/wiki/%28137924%29_2000_BD19 wrote:
<<2000 BD₁₉ is [a ~1km diameter] asteroid with the smallest perihelion of any numbered asteroid (0.092 AU—38% of Mercury's orbital radius). With its high eccentricity, not only does 2000 BD19 get very close to the Sun, but it also travels relatively far away from it. It is one of a small group of Aten asteroids that is also a Mars grazer. Its orbital elements indicate that may be an extinct comet.

It is estimated that 2000 BD₁₉'s surface temperature reaches ~920 K at perihelion, enough to melt lead and zinc, and nearly enough to melt aluminium. 2000 BD19 is considered a good candidate for measuring the effects of Albert Einstein's general theory of relativity because of how close it comes to the Sun.>>

• . https://en.wikipedia.org/wiki/Comet_Encke

https://en.wikipedia.org/wiki/Off_on_a_Comet wrote:

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Off on a Comet (French: Hector Servadac) is an 1877 science fiction novel by Jules Verne.

<<The story starts with a comet called Gallia, that touches the Earth in its flight and collects a few small chunks of it. The disaster occurred on January 1 of the year 188x in the area around Gibraltar. On the territory that was carried away by the comet there remained a total of thirty-six people of French, English, Spanish and Russian nationality. These people did not realize at first what had happened, and considered the collision an earthquake. They first noticed weight loss: Captain Servadac's adjutant Ben Zoof to his amazement, jumped twelve meters high. Zoof with Servadac also soon noticed that the alternation of day and night is shortened to six hours, that east and west changed sides, and that water begins to boil at 66 degrees Celsius, from which they rightly deduced that atmosphere became thinner and pressure dropped. At the beginning of their stay in Gallia they noticed the Earth with the Moon, but thought it was an unknown planet. Other important information was obtained through their research expedition with a ship, which the comet also took. During the voyage they discovered a mountain chain blocking the sea, which they initially considered to be the Mediterranean Sea and then they found the island of Formentera (before the catastrophe a part of the Balearic Islands), where they found a French astronomer Palmyrin Rosette, who helped them to solve all the mysterious phenomena. They were all on the comet which was discovered by Rosette a year ago and predicted a collision course with Earth, but no one believed the astronomer, because a layer of thick fog at the time prevented astronomical observations in other places.

As found by a new research expedition, the circumference of Gallia was 2320 km.

Involuntary travelers through the Solar system did not have any hope for long-term colonization of their new world, because they were lacking arable land. They ate mainly the animals that were left on the land carried away by Gallia. One strange phenomenon, they met was that the sea on the comet did not freeze, even though the temperature dropped below the freezing point (theory that the stationary water level resists freezing level for longer than when a rippled by wind). Once a stone was thrown into the sea, the sea froze in a few moments. The ice was completely smooth and allowed skating and sleigh sailing.

Gallia got to an extreme point of its orbit and then began its return to Earth. In early November Rossete's refined calculations showed that there will be a new collision with the Earth, exactly two years after the first, again on January 1. Therefore, the idea appeared to leave the comet collision in a balloon. The proposal was approved and the castaways made a balloon out of the sails of their ship. In mid-December there was an earthquake, in which Gallia partially fell apart and lost a fragment, which probably killed all Englishmen in Ceuta and Gibraltar. When on January 1 there was again a contact between the atmospheres of Gallia and Earth, the space castaways left in the balloon and landed safely two kilometers from Mostaganem in Algeria.>>

John644 wrote:I am curious to the question, if anyone has considered, using a comet, such as this one, as a vehicle to deliver deep space probes for exploration? ...