New answers tagged

4

The page at the NASA Planetary Data System Planetary Atmosphere Node on the Temperature and Wind for InSight (TWINS) instrument and Pressure Sensor (PS) has a description of the instrument and data production. The native sampling on the spacecraft of the pressure sensor is 20 Hz (20 times a second) but this is normally downsampled to 2 Hz for downlink. There ...


5

This is not a stand-alone answer but is an addition to tfb's answer; but since I provide multiple references, one with a rather lengthly URL, it wouldn't work well as a comment. The homopause altitude at Venus isn't a constant. It varies with latitude, "time of day" (longitude with respect to the subsolar point), and solar activity. This abstract shows an ...


7

You're not overthinking it, but it's not a problem. The important concept is that of the 'homosphere`, which is the part of the atmosphere where it is well-mixed by turbulence. This is the part to the left of the diagram you show, where you can see that the proportions of the various constituent gases in the atmosphere don't change with height. (It's not ...


7

Update 2 The taper ratio formula seems to be correct. The crosscheck stress calculation error mentioned in the Update 1 below is found to be due to: a) incorrectly calculated tether volume (and therefore mass). I assumed a linear change of cross section area across the tether length. In fact, to achieve the uniform strength, a logarithmic increase in erea ...


2

The solar tide is slowing the rotation of Venus down. A general rule of tidal effects on rotation goes like this: tidal forces will cause the angular momentum vector from rotation to match the vector from orbital motion. For example, consider the Earth and its Moon. Earth's rotational vector is pointed north with a magnitude of $2\pi$ radians per day. ...


18

Escape from planetary atmospheres of the terrestrial planets in our solar system is dominated by ions in absolute numbers, as opposed to neutral particle species. Particles can be any type of molecule or atom here, mostly $\mathrm O^{+}$ and $\mathrm N^{+}$ for Earth. For the case of Earth, a particle, once ionised in the upper thermosphere, can couple to ...


7

Basically it is blown away by the solar wind, headed to interstellar space. A light particle in orbit around the Sun will tend to be pushed further out with time because of both solar wind and photonic pressure. Note there are a few pockets of dust around, but they are very hard to see. It takes being in a relatively stable point, usually the L4/ L5 points ...


Top 50 recent answers are included