January 2012 Sky from the Keeble Observatory
My first thought about writing for this first month was to write about calendars
… but I’ll save that discussion for later. Perhaps March, which used to be the first
month of the year! Another notion was to write about all the astronomy “firsts”
that fall into January, ranging from the initial discovery by Galileo in 1610 of
the moons of Jupiter, or the successful landings on Mars seven years ago of the
robotic explorers Spirit and Opportunity.
Instead, I’d like to turn attention from the universe-at-large to what we might
call the universe-at-small. Very small.
A key philosophical component of Western science, dating back to pre-Socratic Greeks,
is the notion of reduction. To understand something, we “take it apart” to find
its smallest constituents. A galaxy is thus an assembly of stars and gas clouds.
Architecture is the rearrangement of “elements” like steel, glass, brick and lumber.
Chemistry is the rearrangement of 100 or so “elements” found in the periodic table.
These elements are personified as “atoms” – the smallest unit of a substance which
remains that substance. (The word comes from a Greek word meaning “can’t be cut.”)
The atoms of the chemist were once thought to be fundamental, until 19th
century physicists started finding smaller pieces – notably the electron. In the
20th century our model of the atom became that of a massive nucleus surrounded
by electrons. Then the nucleus was found to be made of neutrons and protons.
Even there we are not yet at the “can’t be cut” limit, as we find the neutron and
proton be have internal structure – constituents known as quarks, which may indeed
be fundamental. They are made by rearranging just two quarks, whimsically known
as up and down – a proton is two ups and a down, the neutron is two
downs and an up. (Don’t shoot the messenger! I didn’t make up these names!) These
quarks and their four cousins (strange, charm, top, and bottom) can
be rearranged to make up all the known subatomic particles. The model works so well
that it’s now capitalized and dubbed the Standard Model.
But, there are questions that only hinted at but can’t be answered by the basic
version of the Standard Model. A fundamental one is, why do these particles have
mass? (Fundamentally, mass is the property of inertia which causes objects to resist
changes in their state of motion. You’ve probably heard the statement of Newton’s
first law of motion: Objects at rest remain at rest, and objects in motion continue
in uniform straight-line motion unless acted on by an external force.) The current
best answer is … something called the Higgs mechanism. At least, that’s the
proposal attributed to British physicist Peter Higgs, who developed a model which
is mathematically consistent with the Standard Model, in which particles interact
with a pervasive Higgs field. The more they interact, the more massive the
particle. This Higgs field exists throughout space, and can be thought of as something
like a fluid with varying degrees of stickiness. If the model is correct, it ought
to be possible to tweak this field with just the right energy to produce a tell-tale
particle known as the Higgs boson. It is one of the primary objectives of
high-energy physics research to find this particle, sometimes referred to as the
“God particle” for its importance to making the Standard Model work.
The problem with finding it is that it would be extremely short-lived before decaying
into a shower of lighter particles. The theory predicts what those decay products
should be, but not precisely how much energy is required to produce the Higgs boson,
so particle accelerators have been looking over a wide range of energies.
Two research teams at the Large Hadron Collider in Europe have made preliminary
announcements that they may have found the Higgs. May have. Both teams found evidence
at about 125 times the mass of a proton for decay products that could be from the
Higgs, but the statistics of the experiment are not yet robust enough to be sure.
They cite confidence at the “2.6 sigma” level - about 95% - but that’s not sufficient
to declare discovery. They need more data, and should exceed 5 sigma – virtual certainty
– by the end of 2012. Or, the finding could prove to be a statistical anomaly in
the data! Stay tuned.
We’ll have more to say about the Standard Model next month.
Lunar phases for January: First Quarter on the 1st, at 1:15 am;
Full Moon on the 9th, at 2:30 am; Last Quarter on the 16th,
at 4:08 am; New Moon on the 23rd at 2:39 am, and a second First Quarter
on the 30th at 11:10 pm.
Predawn planet watchers will find Saturn and Mars all month. Saturn starts the month
to the south-southeast, about 45 degrees above the horizon. It will move toward
the west and a bit lower day to day through January, ending approximately due south
and about 30 degrees altitude. Mars stays roughly southwest, but drifts lower from
50 to 30 degrees. Mercury is low to the southeast at dawn, rising about an hour
Venus and Jupiter emerge from evening twilight, and both are unmistakably bright
so you’ll have little trouble finding them. Venus will be to the southwest moving
to west-southwest, probably the first “star” you’ll see, and the brightest thing
in the sky excepting Sun and Moon. Jupiter is high to the southeast early in January,
moving to the south by month’s end. It’s not as bright as Venus, but still the brightest
thing in its part of the sky. It’s also above the horizon past midnight, while Venus
Looking overhead about two hours after sunset, you will find the constellation Perseus
at zenith. Its two brightest stars are Mirphak and Algol. The latter is a multi-star
system whose third component was discovered by my undergraduate advisor, Dr. Alan
Meltzer. He had a wry sense of humor, and his joke on this was especially witty
for those Latin students who have read Caesar’s commentaries on the gallic wars
– “Algol is divided into three parts.” Ask a Latin teacher if you don’t get it!
That bright star to the east of zenith is Capella, in the constellation Auriga.
It’s the sixth brightest star as seen from Earth. Below zenith and to the southeast
we have a wonderful alignment. Sweeping your attention downward, you’ll find the
Pleiades, then the constellation Taurus, with its brightest star Aldebaran as the
heart of the Lion. Below Taurus, Orion is rising. Gemini is to the east, with Castor
above Pollux its two brightest stars. Cygnus is setting to the northwest, in an
orientation that makes clear why it is known as the Northern Cross.