The Donnan electric potential arises from an imbalance of charges at the interface of a charged membrane and a liquid but detecting it directly has not been possible. Until now.

This is a suggestion for a way to resolve questions such as:

• How effective are the best FFP3 / N99 masks at breaking transmission of COVID?
• However effective is eye protection when combined with the best masks?
• How effective is ventilation with HEPA filters?

Informed expert opinion can't resolve these questions at present with opinions that range from almost no effect to highly effective. We have many studies but most are observational and from the range of expert opinion it is clear that so far they have had limiations and are not conclusive.

First for anyone who doesn't know, NASA’s perseverance rover is currently collecting small samples of rock and leaving them on the surface in tubes on Mars. NASA want to return them some time around 2033 and they plan to return its Mars samples of rock and some dust / soil to biosafety level 4 facilities (BSL-4). But the ESF in 2012 said we have to contain ultramicrobacteria from Mars and a BSL-4 can’t do that.

See longer version of this post with extra graphics and explanations for non experts.

As Carl Sagan said:

First for anyone who doesn't know, NASA’s perseverance rover is currently collecting small samples of rock and leaving them on the surface in tubes on Mars. NASA want to return them some time around 2033 and they plan to return its Mars samples of rock and some dust / soil to biosafety level 4 facilities (BSL-4). But the ESF in 2012 said we have to contain ultramicrobacteria from Mars and a BSL-4 can’t do that.

[I have a shorter version for experts which leaves out most of the graphics and extra explanations here].

As Carl Sagan said:

If the media, popular entertainment, and retail habits are taken as indicators then the celebration of Christmas is no longer just the reserve of Christians. This has some consequences for the religious and non-religious alike.

In popular culture and the media, Christmas is portrayed as a time of happiness, togetherness, generosity, and peace. In the “made for Christmas” movies, such as those on the popular Hallmark Channel, a “feel good” message is the order of the day.

For those who don’t know the background, NASA’s Perseverance rover is gathering rock samples in Jezero crater on Mars where there used to be a delta long ago. It is a very interesting place for past life. The samples are in tubes on Mars. They want to return them some time around 2033.

Sadly Perseverance can’t drill and the surface deposits have been sterilized by ionizing radiation for billions of years. Though Mars used to have oceans it’s been dry now for billions of years but sometimes with occasional flooding and even lakes for a while.

I am trying to find out what has happened as NASA are normally so careful. The analogy of the smoke detector I think is the best way to think of it.

Open letter to Space Colonization Enthusiasts. It is natural for enthusiasts who are keen on space colonization to think we need no protection for Earth. After all settlers on Mars in science fiction stories rarely run into issues. Even when they find life on Mars, somehow it is never hazardous for Earth. However science fiction is a product of the author’s imagination and is never predictive. Even hard sci. fi. gets some things right and some things wrong. But we are in a world now where what used to be science fiction is becoming reality and it may not be quite as the visionaries saw it.

NASA are planning to return its Mars samples of rock and some dust / soil to biosafety level 4 facilities. That was fine in 2009. But the problem is that it doesn’t contain the very small microbes we now know exist called ultramicrobacteria which can get through a very tiny 0.1 micron nanopore and still be viable.

The samples are in tubes on Mars. They want to return them some time around 2033. The chance of returning life on those mainly geological samples is low. The chance it is dangerous if returned is also likely low. To give an idea of the order of risk I use Margaret Race's analogy of a smoke alarm. The risk of a fire in your house is so low most people don't panic about it. But you still install smoke alarms just in case.

First for anyone who doesn't know about it, NASA are planning to return its Mars samples of rock and some dust / soil to biosafety level 4 facilities (BSL-4). The samples are in tubes on Mars. They want to return them some time around 2033.

This week, scientists from the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) in California,