NIGHT SKY IN MAY

-By Rishi Shah

The night sky of this month displays the elegant beauty of fascinating planets, stars and constellations along with arcane charm of galaxies and nebulae that are spreading all over our universe. As night descends on earth, the zodiacal constellations of Taurus (bull), Gemini (twins), Cancer (crab), Leo (lion), Virgo (maiden) and Libra (scales) are seen unfurling from western to eastern horizon. Constellations Hercules (legendary muscle man) and kite-shaped Bootes (herdsman) with its luminous star Arcturus (Swati) are dominating the evening sky. Dinky Corona Borealis (Northern Crown) is sandwiched between them. Constellations Coma Berenices (Berenice’s Hair), Canes Venatici (hunting dogs) and Leo Minor (small lion) are stretching in western sky. Lyra (harp), Cygnus (swan) and Aquila (eagle) are gliding gracefully in northeastern sky. Their stars Vega (Avijit), Deneb and Altair (Sravana) are sparkling alluringly. The unique Spiral Umbrella Galaxy NGC4651 that is merely thirty five million light-years away is residing in well-groomed Coma Berenices. Its dim intriguing umbrella-resembling structure is extending modestly fifty thousand light-years away further beyond its lurid galactic disk. It allegedly consists of tidal star streams that manifest extensive trails of stars after being gravitationally stripped from unfortunate diminutive satellite galaxy which has been torn apart and eventually absorbed into NGC4651. Apparition of tidal star streams is not uncommon in nearby galaxies in concurrence with the prediction made by galaxy-formation models. Lengthy constellation Hydra (sea serpent) is slithering silently in southwestern sky with puny Corvus (crow), Crater (cup) and Sextans (sextant) straddled on its back. Broad Ophiuchus (serpent bearer) is sprawling in southeastern sky.

Circumpolar constellations Cepheus (king), Cassiopeia (queen), Ursa Major (great bear) and Draco (dragon) are encircling Polaris (Pole Star alias Dhruba Tara) that is dwelling cozily in Ursa Minor (little bear). Faint constellations Camelopardalis (giraffe), Lynx (animal with sharp vision) and Leo Minor are mingling gleefully with these northern constellations. Our galaxy the Milky War runs low along the northeastern and southeastern horizon passing through Cassiopeia, Cygnus, Scutum (shield) and Scorpius (scorpion). Asteroid 4-Vesta is rushing excitedly through Leo. For unlocking the secrets of Vesta’s exceptionally fulgent nature, NASA’s Dawn spacecraft is scheduled to encounter this perplexing rocky entity in August 2011. Eta Aquarid meteor shower peaks on 06 May in eastern sky before dawn. The fantastic flashes of shooting stars which seem to radiate from Aquarius, originate when the petite dusty debris left over by famed Comet 1P/Halley (orbital period of circa seventy five years) slams into earth’s atmosphere and disintegrate dazzlingly. Extraordinary Comets C/2009K5 and C/2009R1 discovered by Australian astronomer Robert McNaught can be marveled as they plough through the cosmic realms occupied by Ursa Minor (skirting Polaris during month’s middle) and the Great Square of winged horse Pegasus (sailing towards chained princess Andromeda in eastern sky before sunup). Comet 81P/Wild tumbles awesomely through Virgo.

Elusive planet Mercury could be glimpsed shortly before morning twilight in eastern sky in Aries (ram). Planet Venus shines mesmerizingly in western sky well after sunset. It is drifting from Taurus to Gemini. Yellow-hued Mars is gleaming in the vicinity of beguiling Beehive Cluster (M44) or Praesepe (meaning cradle or manger in Latin) that resides in Cancer. Praesepe cluster contains over one thousand stars that are gravitationally bound together for a total mass of sheer six hundred suns. This dense star cluster is practically 577 light-years away. Mighty planet Jupiter can be admired in eastern sky before sunrise in Pisces (fishes). Greenish planet Uranus could be discerned in its proximity. Ringed planet Saturn is glinting in Virgo. It is entering eastern sky late at night and floats roughly between giant stars Regulus (Magha) and Spica (Chitra) that are glistening glamorously in Leo and Virgo. Distant planet Neptune is relaxing in eastern Aquarius (water bearer). Far-flung dwarf planet Pluto is loitering lazily in Sagittarius (archer).

Launched in 1990, Hubble Space Telescope (HST) is the largest orbiting public optical telescope in human history. It has now survived twenty years in space and has become one of the most beloved astronomical icons. Built by NASA and European Space Agency (ESA) and weighing moderately thirteen tons this crown jewel of space-based astronomy is hovering fairly five hundred kilometers above in earth’s atmosphere. HST’s cumulative cost has amounted to perhaps ten billion US Dollars. Its optics was repaired successfully in 1993 soon after its operation as the pictures it made were realised to be embarrassingly blurry. (Its main mirror had suffered under spherical aberration due to manufacturing error caused by not correctly polished primary mirror). Named after renowned astronomer Edwin Hubble, HST has been visited by astronauts regularly in five servicing missions undertaken between 1993 and 2009 to replace old, worn out parts and to install efficient state-of-the-art instruments like computers and solar array battery powering aggregate for upgrading its performance. Every time after its rejuvenation HST’s stunning photos boasted of spectacular new views of the universe that bear testimony to the existence of super massive black holes, dark matter and dark energy and of planetary systems beyond our own. It has helped us to peer back to just six hundred thousand years after the birth of our universe that is arguably 13.7 billion years old. HST disclosed confounding composition of our universe, located numerous previously unknown galaxies, identified proto-planetary star systems within several star-forming regions and is still sending superb exceptionally captivating once-in-lifetime images of space objects. NASA in collaboration with ESA and Canadian Space Agency is planning to dispatch infrared space observatory dubbed James Webb Space Telescope that is slated for launch in 2014 and would hopefully work in tandem with HST.

Queer planetary Spirograph Nebula IC418 with its extraordinary textures that mimic multi-faceted celestial diamond was revealed recently by HST. It represents the final stage of evolution of centre star like our Sun that had been red giant star utterly thousand years ago. After ejecting its outer layers substantially into space, it had transformed itself into colourful nebula. The star’s remaining heated core is flooding out ultra-violet radiation into surrounding gas thereby exciting the gaseous glow, which would gradually disperse into space. The star would turn into white dwarf that would then cool down and fade away in billions of years. Our own Sun would expectedly undergo similar fate in barely five billion years from now. Its red colouration indicates gaseous emission of ionized nitrogen (the coolest gas in nebula and is located furthest from energetic nucleus), green points to hydrogen emission and blue traces ionized oxygen (hottest gas and closest to central star). Its name derives from the intricate pattern which imitates drawings created by using Spirograph (baffeling toy that sketches geometric figures specifically, hypotrochoids and epitrochoids) on paper. It lies solely two thousand light-years away in Lepus (hare hopping in southeastern sky). New moon falls on 14 May, while full moon (popularly called flower full moon) occurs on 27 May. Venerated Buddha Jayanti is celebrated respectfully on this day.