ONWARD GROUP XMAS Special 
Well not that special. Just a delicious hot mince pie and a hot drink.
I attach a list of the links and more that we looked at today.
Before that we discussed the new way of measuring a dog's life. Apparently they lead life on a logarithmic scale. So that we have thought that a 2 year old dog was 2x7 years old i.e. 14. The new way is calculated from the equation 
Dog's Age is now n x ln x 16 + 31 [Note ln = natural logarithm]
where n is actual age; ln is the Natural Log of n.
So  2yr old dog = 14 old style and 42 new style
or a 10 yr old dog = 70 old style and 68 new style.
From this we went on to discussing Natural Logs and where they came from and its basis. This in turn led us to 'e'. Here 'e' is a numerical constant that is equal to 2.71828.
From Quora site
Its value is approximately 2.718 and has been calculated to 869,894,101 decimal places by Sebastian Wedeniwski. The number e was first studied by the Swiss mathematician Leonhard Euler in the 1720s, although its existence was more or less implied in the work of John Napier, the inventor of logarithms, in 1614. Euler was also the first to use the letter e for it in 1727 (the fact that it is the first letter of his surname is coincidental). As a result, sometimes e is called the Euler Number, the Eulerian Number, or Napier's Constant. It was proved by Euler that "e" is an irrational number, so its decimal expansion never terminates, nor is it ever periodic.  
Then we got to the list of links. At last!
The first one concerned a Hot White Dwarf. A giant planet orbiting a hot white dwarf star has been discovered for the first time. This sighting is significant because it is first evidence of a world surviving its star's transformation into a white dwarf. This led to comments such as
'The sun: In 4.5 billion years I'm going to burn earth to a crisp.
Just have sufficient vinegar at hand.
Unfortunately, the increasing output of the sun will have evaporated all liquid vinegar in only a billion years or so.'
Then onto a topic that I had fun with when at college in Rugby [1959!!] the Varley Loop Test. This is such a simple and elegant way of finding where there is a fault in a buried cable or one in the ocean. The test can measure the distance along the cable using a derivative of the Wheatstone Bridge. By altering some rheostats the distance is calculated with a simple formula.
Lx = Rx/r
Where, r = resistance of the cable per meter.  
All that is needed is Rx. Read the link to see how it works.
Old, unused fibre optic cables buried underground can be refashioned into seismometers apparently.  Imperfections in the fibres can be harnessed as seismic sensors.  Laser pulses are sent along the cabling, and scatter when they encounter these tiny cracks or faults. The echoing laser light is measured.  A range of 10 km is the maximum currently.
Southern elephant seals thrive under wild freezing currents conditions and spend most of the year at sea. Such seals dive deeper than many whales, with one tracked going down 2,133 meters (6,998ft) down in search of squid and fish.  One seal was fitted with a teeny metallic hat that measures the temperature, conductivity and pressure of water in the Kerguelen area, a remote region in the Southern Indian Ocean. Data collected over 3 months from 80 dives a day down 3300 feet and for 3250 miles. Clever. The idea is to  better understand how much heat the ocean can absorb from the Sun.
There is water ice buried below the surface of Mars, and all you’ll need is a shovel to dig some up . This was found from instruments aboard NASA's Mars Reconnaissance Orbiter (MRO) and its aging Mars Odyssey orbiter. A map has been made and this will help find future landing spots for NASA and Musk.
Scientists have made tremendous progress in understanding that groups of bacteria and viruses that naturally coexist throughout the human body play an important role in some vital functions like digestion, metabolism and even fighting off diseases.  HOW? This links shows how we are finding out. Themetagenomics is one term in this link. Basically pattern spotting in the microbes.
One side of Anak Krakatau collapsed on 22 December 2018. Some blocks of rock are 70-90 m high. Their plunge into the water produced tall waves that tore across the shorelines of Java and Sumatra. A year on and we can see the extent of the damage.  A multibeam echo sounder was brought in to map the seabed. Satellite imagery that only looked at the sub aerial parts of the volcano. Now bathymetry is imaging at 200m water depths and we are seeing triangular-shaped blocks. It shows that less volume of the island was displaced than had been estimated - down from 0.27 cu km to 0.19 cu km. The tsunami still fitted with current models. It was devastating even 50 km away. A good animated site.
Cheops, the Characterising Exoplanet Satellite, is going to investigate distant planets orbiting stars other than the Sun to discover what these alien worlds are made of. It was launched recently. Cheops is a partnership between ESA and Switzerland. This site video explains how it works better that any other I could find. It is clear and straightforward.
5 minute charging of Lion batteries is claimed on this commercial site. The site is a good one with simple graphs and videos to prove that it all works. All we need now is for this to be widespread.
This was as far as we got for discussion. But the rest of the links are interesting with info on ancient air, Nikon close up photos, Glioblastomas blasted by ultrasound and the first liquid hydrogen powered transport ship.