Covid-19 Infection Rates

I wanted to do my bit to highlight the need to socially distance at the moment. In addition to outreach astronomy I’ve worked as a mathematical modeller and simulation programmer for many years. Yesterday I decided to create a very simple demonstration to show how infectious Covid-19 is relative to something like the flu.

The red balls represent new cases of Covid-19 based on one individual passing the virus on and creating a human chain reaction. The blue balls represent the same situation for flu. The simulation shows you how many more Covid-19 people will become infected relative to flu after the same number of transmission waves (9 in this case).

Typically an individual with flu will pass the virus onto 1.3 other people (called the R0 value). With Covid 19 this spreading rate is much higher – between 2.3 and 3. At its worst therefore an infected person will pass the virus onto 3 other people. That might not sound like much but due to exponential growth this level of transmission is like a bomb going off.

Stay safe everyone and please heed the guidelines. With proper social distancing the cascade on the right can be repressed.

Note: This simulation is not validated in any way my medical experts and is for illustrative purposes only.

Developed by S Mackintosh (Mackintosh Modelling & Data Simulations)
modulouniverse.com

 

‘Not too hot and not too cold’

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The Goldilocks zone around three different type of stars

The Goldilocks Zone.  The above image is a great illustration of the relative size of the habitable zone around different types of star, with stars like our Sun at the bottom.

Even very dim M class dwarf stars (pictured top) could harbour planets with liquid water – the planets would just need to be situated much closer in. These stars can have very active magnetic fields however, frequently throwing harmful radiation out towards any orbiting planets.  M class stars are also extremely stable, some destined to burn for over 100 billions years, much longer than our Sun which has around 4 billion years of fuel left.

In the middle we see the K class dwarf stars. These will also out live our Sun (by a factor of 4), have nice wide zones of habitation, and much less magnetic activity than the M class stars.  Potentially these K class stars are the ideal incubators for the slow evolution of life, and there’s plenty of them. Nearly 13% of stars in our galaxy are K class red dwarfs.  That’s approximately 26 billion in our galaxy alone! 

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An artist’s impression of a rocky world orbiting a red dwarf star, like the M and K class stars mentioned above.

Sirius the Glitter-ball

 

A video of Sirius (the brightest star in the night sky) twinkling on the horizon, captured by Steve Brown @sjb_astro. Many people think they’re seeing a low altitude aircraft or UFO when they witness this.

This phenomenon occurs (to a lesser extent) with any bright star low on the horizon due to the vast amount of atmosphere you’re seeing it through. As stars gain elevation, and less atmosphere is between us and them, they shine more steadily, and views are hugely improved.

The difference in the amount of atmosphere you look through with elevation is very striking (as demonstrated in the sketch below).  Particularly for faint deep sky objects like galaxies, high elevations makes a dramatic difference to the quality of visual or photographic images you’ll collect.

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How much atmosphere you look through with observing angle.  At the zenith (overhead) you look through over 2/3 less atmosphere than at the horizon.

Star Stories Astrophotography Special

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Eric presenting his guest talk up at Abriachan

There were only a few stars up at Abriachan Forest tonight for our Star Stories Astrophotography special, but some nice early views of the waxing crescent Moon and Venus before the weather really turned and a mini snowstorm descended.

Many thanks to our guest speaker Eric Walker from the Highlands Astronomical Society for delivering a fantastic talk on astrophotography.  Eric showcased a ton of amazing images he’s taken over the years demonstrating his passion for astronomy and observing.

Clelland also entertained in the round house with storytelling and we had a nice impromptu discussion about the night sky over the campfire between changeovers.

The next Star Stories is our Vernal Equinox special in March, which will be the last opportunity for dark sky observing this season before the return of longer days.

Eventbrite link here

Urban Astronomy Aurora Special

Many thanks to Graham Bradshaw of Graham Bradshaw Photography for tonight’s fascinating guest talk on hunting down and photographing the Aurora. Here’s one of the beautiful time lapses Graham shared with us during his presentation.

 

Graham also provided a lovely selection of his images (see below) along with camera settings to help budding night sky and aurora photographers.

We also took advantage of some clear breaks in the sky after the talk and walked up to the Nature Reserve to view some bright constellations and star clusters.

Thanks to everyone who came along. The next Urban Astronomy event is our Venus special on March 12th. Booking link here.

Stargazing in the Outer Hebrides

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Pre dawn Milky Way on the Isle of Lewis, during the 2020 Hebridean Dark Sky Festival

As a family we’ve visited the Western Isles of Scotland during the warmer summer months, attracted by the wild open spaces, stunning beaches and abundant locations for camping.  Unfortunately the long summer days and short nights are too bright to stargaze, so I’ve never had the opportunity to sample the fantastic dark skies the island has to offer.  I therefore jumped at the opportunity of participating in this year’s Hebridean Dark Sky Festival, organised by An Lanntair and programmed by Andrew Eaton-Lewis.

My outreach involved delivering astronomy talks and stargazing events at community hubs across the island of Lewis.  Over three nights on the island I visited communities at Balallan, Comunn Eachdraidh Nis in North Lewis and the aptly named Edge Cafe over in the west at Aird Uig.

Despite some very wild weather both before and during the festival the three events were a big success, with starry skies materialising in some form at each session.  Skies, when clear, were astonishingly dark, with star clusters and galaxies clearly visible with the naked eye and a glorious sweep of Milky Way evident between the fast moving weather.

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Starry skies from Ness Beach

When presenting my stargazing talks in Scotland I always try to persuade people of the merits of binocular and naked eye observing over telescopes when weather conditions are changeable.  This mantra was well demonstrated during these events, with the agility of binocular observing allowing us to quickly head in and out when breaks in the sky presented themselves.

Travelling to each event in my camper van and sleeping out in the wilds was also a memorable experience.  Wind, sleet, rain and hail all assailed me at various points during my wild camps, but I was always rewarded with frequent starry skies opening above me when I headed out for fresh air.

The people of the island are also some of the friendliest folk you could meet, with Highland hospitality well in evidence wherever I went.  Bounteous servings of tea and cake were never far away!

I very much look forward to participating in the festival again and encourage anyone with an interest in stargazing to consider the Outer Hebrides as a viable winter destination, particularly if you’re seeking some of the very best dark skies available.

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Satellites aplenty

Venus and Mercury

85024035_2842536592490527_233392740522524672_o.jpgThis is how low Mercury grazes the horizon at the moment. A superb shot of Venus and Mercury from Will Cheung this evening.

If you want to sight Mercury for yourself the best chance is right now in the early evenings just after sunset.  Using Venus as a guide, scan the low horizon with binoculars or naked eye.  An unobstructed horizon like the one in the picture above is essential.

Clear skies.