Astronomy / Space Pleiades, Tabby's Star, Wolf-Rayet Stars, Super-Earths + more in Feb Astronomy Now

[Para Handy]

Pleiades, Tabby's Star, Wolf-Rayet Stars, Super-Earths, dry Mars and interview with Jocelyn Bell-Burnell on "50 Years of Pulsars" and lots more in February Astronomy Now (UK magazine).

Some decent articles in the February Astronomy Now - a really good piece on the Pleiades including the Maia manganese anomaly, small report on Tabby's Star progress, examination of Wolf-Rayet winds, discussion on "Super-Earths" and studies doubting "current liquid water surface activity" on Mars. Of course, a lot more besides that and a Jocelyn Bell-Bunell interview is well done.

 

[Don Alvarez]

studies doubting water on Mars....

I thought water on mars was a settled notion

https://www.wired.com/story/scientists-discover-clean-water-ice-just-below-mars-surface/

 

[Para Handy]

I thought water on mars was a settled notion

https://www.wired.com/story/scientists-discover-clean-water-ice-just-below-mars-surface/

Quite right, I did not make my sentence sufficiently clear, it reads awful to me now so I shall edit in the missing word - "liquid". LOL ***EDIT*** I have amended that part to read "current liquid water surface activity".

The article is looking at the theories about and studies of the features on Mars' surface which had led to speculation that there were currently-active mechanisms involving liquid water at the surface - Recurring slope lineae (RSL) - the dark streaks seen to be descending on crater slopes etc.

The presence of water ice is agreed and there is of course possibility of liquid water in underground aquifers.


So - apologies for my misleading wording - caused by trying to present too brief a post.

 

[Jonny Shiloh]

The article is looking at the theories about and studies of the features on Mars' surface which had led to speculation that there were currently-active mechanisms involving liquid water at the surface - Recurring slope lineae (RSL) - the dark streaks seen to be descending on crater slopes etc.

I've not read the article but I believe I've read recently that the current theory about RSL now favours sand flowing down the side of the crater slopes, did I remember that right?

 

[Para Handy]

I've not read the article but I believe I've read recently that the current theory about RSL now favours sand flowing down the side of the crater slopes, did I remember that right?

Yes indeed - by using stereo imaging they determined that the angle of the slopes where the RSLs occurred was above the angle at which you get flows of dry sand. The RSLs also "peter out" when the incline reduces towards the bottom of the slope. If liquid were involved it would be able to flow at shallower angles.

They still don't know what mechanism causes these to appear in warmer seasons and fade during winter and what produces the "fresh material" that starts the slide off.