The Wonders of Andromeda

How the Andromeda Galaxy reveals itself through standard sized binoculars (say 10x50s).  For reasons that are mainly due to the human eye's sensitivity to low colour light levels, deep sky objects such as galaxies and nebulae appear as in greyscale through both binoculars and telescopes.  This is due to their low surface brightness... we've all been spoilt by DSLR camera and CCD images!

ANDY FLEMING takes a look at a constellation everyone can see without optical aids, and how at a dark site if you follow the instructions you’ll observe the most distant object you’ll ever see with your naked eyes: the Great Spiral Galaxy in Andromeda.

Okay, so I’ll admit it. I share the typical mammalian trait of laziness including when it comes to observing the night sky. I also exhibit a modicum of tightness when it comes to spending money on equipment in our damp and cloudy climate.  So I’ll use the excuse straight away of two eyes being better than one, and say that even with my superb eight inch Newtonian reflector, my enjoyment of the night sky still comes primarily from a pair of 10 x 50 Super Zenith binoculars that I purchased for a fiver at a local car boot sale.  They are light, portable and require no setting up.


These binoculars have, over the past four years facilitated access to some stunning clestial sights, often when the use of my telescope has been impractical, such as when I’ve been out walking our dogs, or during those all-too-brief clear spells. They are also nicely portable for a quick to get away from the worst of the Teesside light pollution.


One of my favourite constellations is Andromeda, well it has to be hasn’t it... just consider the title of my blog.  And I thought that the time had come to pay homage to this constellation upon which my literary internet presence is based.

How to locate the Constellation of Andromeda in the night sky. Image courtesy of Stellarium Planetarium Software (screen dump).

The constellation of Andromeda is located in an interesting part of the sky, being flanked celestially by the constellations of Cassiopeia, Pegasus, and Perseus. It is a circumpolar constellation which means it can be viewed the whole year long in mid-northern climes.  It also possesses a rather interesting legend that has been passed down to us from antiquity, infact it is one of the most famous of all the Greek celestial legends. It’s also a fascinating constellation because within it is located the spectacular great spiral galaxy M31 visible with the naked eyes and the other giant spiral galaxy along with the Milky Way in our local cluster.  It is the most visible galactic deep sky object seen from the northern hemisphere.


And so to that fascinating Greek legend which has it that Perseus, killer of the Gorgon, Medusa, had a glance that could turn anyone to stone. He also possessed an unfair advantage, as the gods had provided him with a pair of winged sandals and a shield that he could use to locate Medusa (thus looking only at her reflection, and not the Gorgon herself).  After neatly slaying Medusa, Perseus was returning home when he saw the beautiful Princess Andromeda, inexplicably tied to a post on the seashore.  It turned out that Andromeda’s mother, Queen Cassiopeia, had fallen foul of the sea god Poseidon, and as a punishment, Cetus, a monster had been sent to ravage the country. King Cepheus, after consulting an Oracle was told that the only way to placate Neptune was to sacrifice his daughter to the monster.


However, a timely appearance was made by Perseus who turned the beast to stone and then married Andromeda.  All the major players in this fairly unique happy-ending were thus cast into the sky by the Greeks, and all can be seen around Andromeda. Even the sea monster, Cetus, is on view, although he was relegated to the status of a harmless whale!  Such are the outcomes of Greek myths!


And so to the jewel that is Princess Andromeda’s crown, the Andromeda Galaxy, and my easy instructions for its location at-a-glance.  Bear in mind that to view this object with the naked eyes you do need to view the night sky at a reasonably dark site.  You will have difficulty observing it in the centre of an urban area... the suburbs or local countryside will prove to be much more successful.

How to locate the Andromeda Galaxy (M31) in the night sky. Image courtesy of Stellarium Planetarium Software (screen dump).

Firstly look for the constellation of Cassieopia, the great ‘W’ in northern hemisphere skies.  Once again like Andromeda it is a circumpolar constellation at mid northern latitudes.   Well below Cassieopia, and slightly to the right, in an area devoid of bright stars, you will see one lonesome bright orange star, the double star Mirach (Beta Andromeda). Star hop up and slightly to the right two faint stars (Mu and Nu Andromeda) are visible.  Slightly to the right of Nu is a faint star-like speck – that’s the Andromeda Galaxy (Messier object 31, or just M31). This of course is not the only method by which to find our closest galactic neighbour, but it’s the one that I personally find easiest.


But take a look at it through any common or garden binoculars and you’re in for a jaw-dropping sight. What you see is a large hazy nebulous-looking entity that in fact is a part of a gargantuan star city containing hundreds of billions of stars... it is the central bulge of this fabulous spiral galaxy.  Some more details are revealed with a telescope with a low power eyepiece, but in truth I’ve always found M31 a disappointing telescope target – it’s definitely far better with binoculars due to their intrinsically larger field of view.


As you view our beautiful galactic neighbour, consider that its distance from the Earth is approximately 2.5 billion light years.  In other words light the fastest thing we know with a huge velocity of 186,000 miles per second has taken 2.5 billion years to reach our eyes from the Andromeda Galaxy. The light from it we see today left M31 before humans had evolved from apes!  In motorway terms its distance is a staggering 14,750,000,000,000,000,000 miles!  In space it's a long way between service areas!


There is one final twist in this tale of cosmic distances. The Andromeda Galaxy is on the move – and quickly at 120 kilometres per second. And it’s coming towards us! In 3 or 4 billion years from now our own Milky Way and M31 will merge in a celestial show of galactic cannibalism. Will our solar system and the Earth survive?

Mars The Wonderworld: We’re Just 3.5 Billion Years Too Late!

NASA's Hubble Space Telescope took this snapshot of Mars 11 hours before the planet made its closest approach to Earth on August 26, 2003. The two planets were 34,648,840 miles (55,760,220 km) apart. This image was made from a series of exposures taken with the Hubble Space Telescope's Wide Field and Planetary Camera 2. Photo credit: NASA/J. Bell (Cornell U.) and M. Wolff (SSI).

Evidence is mounting that Mars was once a wet and warm world, similar to the early Earth. What went wrong with the Red Planet -- is it possible that future explorers may find fossils from a more habitable time -- indeed did microbial life survive until the present time?  ANDY FLEMING investigates.

Once upon a time there were two adjacent planets orbiting a run-of the-mill star in one of the arms of an unremarkable spiral galaxy.  Both were warm, both were wet, both had substantial atmospheres, both had vulcanism, both had oceans, seas and rivers, and both were in or on the edge of their star’s habitable zone.  Life, we are certain began on one, but on the other – well we’re not too sure.  The planets in question are of course the Earth and Mars.

Everyone is fascinated by Mars.  From an earlier less-informed age, science fiction by Ray Bradbury and Edgar Rice Burroughs, or the imagined canals of astronomer Percival Lowell has fired our imagination, and has ensured that the Red Planet now has a special place in both our hearts and popular folklore.  The real Mars is even more fascinating however, and the planet’s formation and history can be the subject of some fascinating speculation.  Mars is still one of the few places in the solar system that humans can think realistically about exploring on foot.

Did life arise on Mars in its early past like it did on Earth?  Even more speculative, did life arise on one planet, only to be transported by ejecta to the other after an asteroid impact?  Many scientists think that life, well microbial life at any rate, protected from cosmic rays and a fiery entry into the Earth’s atmosphere inside a space rock can traverse the vast distances between planets.  One of the meteorites discovered on the snows of the Allen Hills of Antarctica  showcased by NASA in 1996, and confirmed as Martian by isotopic analysis, contains tantalising crystal structures that may be either chemical in origin or fossilised bacteria (albeit very small bacteria!).  Meteorite ALH84001 may surprise us yet.

A vast ocean covered the northern lowlands of Mars some 3.5 billion years ago, suggest planetary scientists.

Will future geologists as they explore Mars discover fossils in the sedimentary rocks that are so indicative of the planet’s wet and warmer past?  Did creatures swim in the seas and rivers of Mars – were they washed up on the now high and dry fossilised Martian beaches that we’ve identified with our Mars orbiters?  Did they take the ultimate white-knuckle ride over waterfalls to dwarf Niagara in the Vallis Marineris, a gargantuan canyon the width of North America?  As the late NASA astronomer and planetary scientist Carl Sagan (1994) speculated, “Now that would be a world to explore – unfortunately we are four billion years too late!”

Whether such speculation turns out to be confirmed, things started to go wrong about 3.8 billion years ago, about the time life got started on Earth.  Mars is about half the size of the Earth so its interior began to radiate heat to space much more quickly and its core began to solidify.  Without a molten iron core acting as a dynamo, any magnetic field surrounding the planet started to dissipate exposing the atmosphere and surface to the Sun’s charged particles.  Any tentative carbon cycle would grind to a halt too -- despite having the largest volcano in the solar system (Olympus Mons), vulcanism would cease, and with it any possibility of recycling the planet’s carboniferous rocks.

In addition, with its gravity and hence escape velocity only 40% that of the Earth, and with no protective ozone layer,  ultra violet radiation would pummel the Martian atmosphere disassociating water and carbon dioxide molecules into their constituent atoms with hydrogen and oxygen drifting  off into space.  With steadily decreasing atmospheric pressure, the Martian greenhouse effect would be thrown into reverse.  Temperatures would plummet, the planet’s remaining water would freeze either in permafrost or subterranean glaciers, and life, if it had existed would be forced to retreat into the last protected under- the-surface niches and habitats.

Is it still there, hiding in the caves of Mars or in the subsurface soils, clays and rocks, away from the desiccated, radiation-fried environment above?  Is this the cause of the methane out gassing detected by NASA – or does this possible bio-signature have chemical or volcanic origins?

We know from a plethora of studies in some of the most inhospitable places on Earth such as Antarctica, deep in the oceans, in sulphurous volcanic springs, even in nuclear reactors and in solar radiation-saturated NASA hardware brought back by astronauts from the surface of the Moon that extremophiles are tenacious in the extreme!  Once life has a foothold, extinguishing it is phenomenally difficult.

A view of the boulder-strewn field of red rocks reaches to the horizon nearly two miles from Viking 2 on Mars' Utopian Plain. Image credit: NASA

However, NASA/JPL’s’s two Viking spacecraft that touched down in mid-1976 gave inconclusive results in their analysis of the Martian soil.  Gases were exchanged when a nutrient soup was added to the soil, but no organic molecules were found on the Martian surface.  However, the Vikings were designed to detect only a small subset of possible life – that found on the Earth.  There’s no guarantee that extraterrestrial bugs will adhere to terrestrial rules.

NASA/JPL’s Mars Science Laboratory is slated for launch in 2011, and with a battery of on-board tests and equipment may start to provide some more substantial tantalising evidence of the signatures of life.  Previous unmanned spacecraft have participated in NASA’s “follow the water” initiative --both the Spirit and Opportunity Mars Exploration Rovers have found abundant evidence of sulphate rocks formed in water and stratified sedimentary rocks exposed on the Martian surface.  The Mars Phoenix lander found copious amounts of water ice underneath its landing site, and evidence of perchlorate-saturated water condensed on its legs.

Mars is still a fascinating, enigmatic and lovely world with wonders aplenty to keep our robot emissaries, and eventually astronauts busy for decades and centuries to come.  Its river channels, waterfalls, lakes and seas may now be desiccated, and its warmest days may be barely above the freezing point of water, but finding life on the Red Planet has been a dream of humanity for centuries.  And sometimes dreams come true.

Bibliography

Sagan, C., Pale Blue Dot: A Vision of the Human Future in Space, Random House, (November 1994)

Astronomy for Everyone: Jupiter-fest!

The innermost of Jupiter's Galilean satellites, Io, superposed in front of the gas giant planet. To the left of Io is a dark spot that is Io's own shadow. A solar eclipse would be seen from within the shadow spot on Jupiter. Viewed from planet Earth, similar shadows of Jupiter's large moons can often be seen crossing the giant planet's disk. (Credit: NASA/Cassini spacecraft imaging, 2004)

In this edition of Astronomy for Everyone, ANDY FLEMING reports that our solar system’s largest planet right now is providing some stunning views in the night sky.

It was during the evening as we drove back along a tree-lined country road after an interesting public talk at our local planetarium, that the receding clouds revealing a stunning large bright object on the eastern horizon that seemingly was following the motion of our car through the hedges.

On our ten minute journey it became very apparent why, to the uniformed observer, an apparition of this celestial object at times bears all of the classic features of an unidentified flying object.  To those in the’ astronomical know’ however there’s no doubt that this is the king of the entourage of our Sun’s eight planets... Jupiter.  It’s the fourth brightest object in our night sky and there is only one other planet that’s even brighter and that’s Venus.  They can’t be confused as Venus being closer to the Sun is always in the west near our star at dusk.

The view of Jupiter through a small telescope, along with its four Galilean moons.

Repeated observations over the course of one evening reveal, just like Galileo Galilei discovered in the seventeenth century, that these tiny objects are in motion orbiting this huge planet.  They are Jupiter’s four largest moons; it’s so called Galilean satellites after their discoverer and are named Io, Callisto, Ganymede and Europa.  They’re all fascinating and enigmatic worlds in their own right, and they suggested to Galileo that the Earth is not at the centre of the heavens, thus laying bear the conceit of the geocentricism. Later discoveries concluded that this mini solar system contains many more moons, and new ones are regularly discovered, the present total being sixty three. Through binoculars it’s also apparent that Jupiter is a disk, another clue to it being another world, rather than a star.

However you observe it telescopically, Jupiter is a treasure trove, and a small refractor will show the planet’s beautiful ever-changing and fast-moving clouds and their bands, a result of immense jet streams in Jupiter’s upper atmosphere.  A larger refractor or reflector will allow observations of the solar system’s largest storm... its great red spot, which is infact a huge anti-cyclone or area of high pressure that has been observed in the planet’s atmosphere for the past four hundred years.

Jupiter has no solid surface, and with the volume of the planet being the equivalent of over 1,300 Earth’s many scientists regard it as a failed star with the right elemental constituents in its atmosphere but with too low a gravity to ignite nuclear fusion.  Infact, its gravity is still so strong that it is a powerful source of radiation and its ionising effects are felt even as far away as the orbit of Saturn.  Jupiter also generates much internal heat.  Indeed, if it had been a few times larger it would have qualified as a brown dwarf star.  It’s a massive ball of hydrogen and helium gas with traces of contaminants such as ammonia and methane at frigid temperatures, these latter two gases being responsible for providing the beautiful colours in its atmosphere. Delve further down in its atmosphere and the immense pressures dictate that these gases liquefy.  Delve even deeper down to the planet’s core and scientists believe that lurking at the centre is a ball of liquid hydrogen surrounding a rocky core.

I am lucky enough to own two telescopes, an eight inch custom-built Newtonian reflector and a four inch Celestron 102SLT ‘go to’ refractor.  Although more details of Jupiter’s atmosphere are available using the better light gathering capabilities of the larger instrument, my favourite views of Jupiter are now through my new refractor.  Using the same eyepieces they’re sharper and the clarity is far better...my favourite views are through a 26mm Plössl eyepiece with a double magnification Barlow lens.

Fancy taking a peek at the fifth planet from the Sun and our solar systems largest? Well now is a great time especially for observers in mid northern latitudes.  As I write this in early December, Jupiter is high in the sky by mid-evening and is a magnificent sight.

Unlike its 2010 apparition when it barely made 10 degrees above the southern horizon which made observing difficult due to the Earth’s atmospheric turbulence, it is now high in the sky and really bright at magnitude -2.6.  As an added bonus, unlike in 2010 (when it had disappeared) the south equatorial band is now showing up strongly again.

So get yourself outside and try detecting the bands and the moons with binoculars. With a telescope, try sketching the positions of the four Galilean moons relative to Jupiter. Date and time your sketch and download and use free planetary software such as Stellarium to discover which moon is which.  The king of the planets has wonders aplenty to keep you busy for hours.