Coincidence, serendipity, happenstance – call it what you will. The Universe and life sometimes seem to be ruled by these.
We are lucky to live at a time when total solar eclipses are possible. The Sun’s diameter is 400 times that of our Moon but it also lies about 400 times more distant. This remarkable coincidence means that both objects have the same apparent size in the sky. If New Moon falls when the Sun and Moon are in conjunction then a solar eclipse occurs. However, the Moon’s distance from Earth increases a little over 3cm per year due to tidal acceleration. The result is that approximately 600 million years hence solar eclipses will no longer be possible because the Moon’s apparent diameter will then be too small to cover the Sun’s disk.
To support life, elements must bond together to form molecules. Two factors are required to allow molecular bonding. They are:
* Strength of the force of electromagnetism
– If the force of electromagnetism was greater, atoms would not share electrons with other atoms
– If the force of electromagnetism was weaker, atoms could not hold on to electrons at all
* Ratio of the mass of the electron to the mass of the proton
– If the ratio isn’t delicately balanced, chemical bonding could not take place
Atoms must be able to form to provide the elements required for life molecules. To support formation of atoms, the strong nuclear force, the weak nuclear force and gravity must each be delicately balanced.
* The strong nuclear force determines the degree to which protons and neutrons (some components of atoms) stick together.
– If the strong nuclear force was slightly greater (0.3% stronger) life would be impossible because all protons and neutrons would bind together. There would be only heavy elements in the universe.
– If the strong nuclear force was slightly weaker (2%) life would be impossible because protons and neutrons would not stick together. Only one element, hydrogen would exist in the universe.
* The weak nuclear force governs the rates of radioactive decay
– If the weak nuclear force was much stronger, matter would be converted into heavy elements
– If the weak nuclear force was much weaker, matter would remain in the form of the lightest elements
* The strength of the force of gravity is one of the determinants of how hot the stars burn
– If the force of gravity was stronger, stars would burn up too quickly and erratically for life to exist
– If the force of gravity was weaker, stars wouldn’t be hot enough for nuclear fusion; no heavy elements would be produced.
There must be the right number and mass of protons, neutrons and electrons in the universe in order to have life.
* Neutrons are and must be 0.138% more massive than protons
– If neutrons were an additional 0.1% more massive, there wouldn’t be enough of them to make heavy elements necessary for life.
– If neutrons were 0.1% less massive, protons would more rapidly decay into neutrons and all the stars in the universe would have collapsed.
* The number of electrons must be equal to the number of protons
– If the numbers of protons and electrons aren’t balanced, galaxies, stars and planets would have never formed because electromagnetic forces would have overcome gravitational forces.
The rate of expansion of the universe is how it must be to support life.
* If the universe expanded more quickly, matter would disperse and not form into galaxies, stars or planets.
* If the universe expanded too slowly, matter would clump too much and the universe would collapse in a super-dense lump.
Doesn’t it make you wonder?
I did too after briefly discussing the idea of writing with someone last Monday evening. The Brazilian author Paolo Coelho came up in conversation and I mentioned whenever he finds a white feather he takes it as a sign to write a new novel. Later that night I was coming out my front door and looked down. There, on the ground, was a white feather.
The Universe really does amaze.
For further reading “The Goldilocks Enigma” by Paul Davies explores the fine tuning debate while “Just Six Numbers” by Sir Martin Rees is also an elegant overview of the subject.
Sara and John
The wedding of Sara Beck and John O’Neill is tomorrow in Topsfield, Massachusetts and I’m sure you will join me once again in sending every best wish on their special day.
Solar cycle on the up
Aurora activity picked up the last couple of days when high-latitude sky-watchers saw wonderful displays of the northern lights after violent solar storms. Skies were cloudy over Ireland but elsewhere observers were treated to a late-Summer sky-show. Read more about the events at http://www.universetoday.com/ where you’ll also find links to videos of the recent aurora displays.
Sparks in the dark
The dependable Perseids are predicted to peak at 23h (midnight Summertime) on August 12th and conditions are ideal with the 2 day old Moon setting just before 20h 30m. The double peak noted a few years ago now seems to have merged into the traditional maximum but the International Meteor Organisation ( www.imo.net ) suggest the complexity of the Perseids means high rates may persist over a period of almost a full day.
Deirdre Kelleghan has sent mention of a new initiative called Meteorwatch ( meteorwatch.org/ ) which is prompting interest in the Perseids. Everyone is encouraged to get outside and look up if the skies are clear.
Midlands Astronomy Club is hosting their annual Perseid watch this weekend. People can join them at their Observing Site in Clonminch just outside Tullamore this Saturday August 7th. MAC will supply the barbecue and camp-fire. All you need to bring is food, implements and a tent and whatever else you think you need. They plan to meet from around 8:30/9:00pm and you can stay as late as you want.
The Irish Astronomical Association will be holding a ‘Perseid Party’ at Delamont Country Park, near Killyleagh, Co Down, just off the A22 between Killyleagh and Downpatrick, on the evening of Thursday 12th, or if the weather is bad that evening, on the following night, Friday 13th, assuming it’s not a washout too! This will be a ‘Fry-up’, rather than a BBQ, so bring any sort of a gas or spirit cooker you may have, plus frying pan, and whatever grub & drinks you want. For more details and updates re the weather decision for Thursday or Friday night, see www.irishastro.org
A fascinating celestial waltz takes place above the western skyline this month as Venus (magnitude –4.3), Saturn (1.1), and Mars (1.5) trade places on the evening sky stage. The trio form a sharp isosceles triangle on the 1st but the symmetry is ruined by the end of the first week as Venus passes Saturn and closes on Mars.
As the month progresses the grouping is getting lower and lower in the evening twilight so an unobstructed horizon will be a prerequisite to spotting them.
A small telescope will show Venus at half-phase in mid-August while the rings of Saturn will be seen to have opened up just a fraction more.
The slender lunar crescent joins the scene on August 13th. As the curtain falls on the western sky drama you’ll find Jupiter appearing above the eastern skyline. At magnitude –2.8, the planet dominates the constellation of Pisces, one of the watery groups in an area of sky known as the Celestial Sea. Jupiter rises at 22:00UT at the beginning of August and by 20:00UT at the end of the month. Bottle-green Uranus is in the area too — the magnitude 5.8 planet lies in the same low-power binocular field as Jupiter all month (Uranus is a naked eye object from a dark site.)
Mercury is too close to the Sun to be seen this month.
There was drama on the International Space Station this week when one of the cooling pumps broke down and prompted Nasa to schedule emergency spacewalks. A full rehearsal of the repairs has been carried out at Nasa’s training facility and reviewed by the mission managers. The procedures will be transmitted to the ISS crew who will then evaluate them in conjunction with ground controllers. The actual spacewalks are scheduled for this Saturday and next Wednesday but check http://www.nasa.gov/mission_pages/station/main/index.html for any updates. The current ISS crew are Tracy Caldwell Dyson, Shannon Walker, Doug Wheelock, Fyodor Yurchikhin, Mikhail Kornienko and Alexander Skvortsov.
The ISS is currently making a series of morning passes over Ireland and you can find predictions for Terenure, Dublin at http://www.heavens-above.com/?Loc=Terenure&Lat=53.300&Lng=-6.283&Alt=65&TZ=GMT – change to your own locality via the “select your location from our database” feature of the site.
Out and about
Astronomy Ireland lecture on August 9th
Dr John Quinn will give the next Astronomy Ireland lecture in Trinity College Dublin on Monday, August 9th at 8pm. The lecture is titled “The Extreme Universe” and Dr Quinn will talk about his work in using special telescopes to investigate gamma-ray sources in our Universe.
The Universe looks very different when viewed using gamma-rays, as opposed to visible light: some sources of gamma-rays are thought to be massive exploding stars, known as supernovae, collapsing neutron stars, and black holes. These objects are some of the most fascinating and extreme objects in the Universe.
Dr Quinn is one of the Irish scientists who is a member of the VERITAS collaboration, and his work involves studying active galaxies (galaxies that emit very strong radio waves from their cores), and super-massive black holes which lurk deep inside these galaxies.
More details from www.astronomy.ie
IAA SOLAR DAY, WWT, CASTLE ESPIE, 15 AUGUST
The IAA will be holding another one of their popular ‘Solar Days’, at 2 p.m. on Sunday 15 August, at the WWT, near Comber, Co Down. We’ll have the usual selection of solar telescopes, binoculars etc, to view the Sun in visible light, H-Alpha, etc. And we’ll have the portable planetarium too for star shows, so even if it’s cloudy, come along. Bring any solar observing equipment you may have. It’s free admission if you bring a telescope or filtered binocs, otherwise normal admission charges apply. More details on www.irishastro.org
DOUBLE PUBLIC LECTURES AT QUB, 31 AUGUST
The Astrophysics and Planetary Science Department at QUB and the Irish Astronomical Association are jointly hosting a free double public lecture in the Larmor Lecture Theatre, Physics Building, QUB, Belfast. This event, arranged by Professor Stephen Smartt, has been planned to coincide with a major professional conference on Pan-STARRS, but that is open only to registered professional participants.
The two speakers are each world-renowned experts in their fields, and very good speakers, so this is a treat not to be missed!
Prof Carlos Frenk, FRS, Director of the Institute for Computational Cosmology, University of Durham, will give a lecture entitled “From the Big Bang to the Universe of Galaxies”, and Prof Chris Stubbs, Chair of the Department of Physics at Harvard University, will speak on “The Accelerating Universe: A Crisis for Fundamental Physics”. Don’t be intimidated by the titles – these lectures will be aimed at a non-specialist public audience.
The event will be from 7.15 to 9.00 p.m. Remember, it’s free, but admission by ticket only, so apply right now!