Archive for May 18, 2020

Hubble Tension in Perspective

Posted in The Universe and Stuff with tags , , , on May 18, 2020 by telescoper

In my office today for the first time in a couple of months I stumbled across a folder containing the notes from the summer school for new Astronomy PhD students I attended in Durham in 1985. Yes, that’s thirty five years ago..

Among the lectures was a set given by Richard Ellis on Observational Cosmology from which I’ve taken this little snippet about the Hubble Constant:

It’s not only a trip down memory lane but also up the cosmological distance ladder! You will see that there were two main estimates, one low and one high. Both turned out to be about three sigma away from the currently-favoured value of around 70.

Plus ça change, plus c’est la même chose…

Does this change your mind about today’s tension between another pair of “low” (67) and “high” (73) values?

Phase 1 Commences

Posted in Biographical, Covid-19 on May 18, 2020 by telescoper

So here we are then. Phase One of the relaxation of Ireland’s Covid-19 restrictions begins today. The focus will be on the extent to which people continue to follow the rules while the modest loosening of restrictions takes place.

Here is the most recent log plot summarising the Covid-19 epidemic in Ireland. I’m keeping track of the numbers here.

Yesterday only 64 new cases were reported, the lowest since mid-March, along with 10 deaths.

Here is a plot of new cases on a linear scale so you can see the decline more easily.

And the mortality figures look like this:

Data and explanatory notes can be found here.

The signs are thus optimistic but I think its very sensible to take this in slow stages. It remains perfectly possible for infection to spread again if the remaining precautions are not taken seriously. By and large, though, people have been sensible so far and I’m hopeful.

I shall shortly be attempting to remember where my office is so I can go in and deal with some online assessments.

I suppose it won’t be long until we start getting instructions on how to prepare for Phase 2.

Update: I made it into the Department where I noticed the evidence of the last time I was there!