KEPLER'S 715 EXOPLANET BONANZA

This image from NASA's Kepler mission shows the field of view possessed by the space telescope. In particular, an expansive star-rich patch of sky in the constellations Cygnus and Lyra stretching across 100 square degrees, or the equivalent of two side-by-side dips of Ursa Major, the Plough or Big Dipper. 

A cluster of stars, called NGC 6791, and a star with a known planet, called TrES-2, are outlined. The cluster is eight billion years old, and located 13,000 light-years from Earth. It is called an open cluster because its stars are loosely bound and have started to spread out. TrES-2 is a hot Jupiter-like planet known to cross in front of, or transit, its star every 2.5 days. Kepler has spent four years hunting for transiting planets that are as small as Earth. (Credit: NASA/Ames/JPL-Caltech).

The important news in the exoplanet hunting community at the moment is that NASA has recently announced that its Kepler space telescope mission has discovered no fewer than 715 new planets in multiple-planet systems much like our own solar system.

Most of them are smaller than Neptune, which is almost four times the size of Earth. This

discovery marks a significant increase in the number of known small-sized planets more akin to the Earth. John Grunsfeld, associate administrator for NASA's Science Mission Directorate said, "That these new planets and solar systems look somewhat like our own, and portend to a great future when we have the James Webb Space Telescope in space to characterize the new worlds.”

Since the discovery of the first planets outside our solar system roughly two decades ago, verification has been a laborious planet-by-planet process. Now, scientists have a statistical technique called multiplicity that can be applied to many planets at once, when they are found in systems that harbour more than one planet around the same star. It relies in part on the logic of probability, it is a process that ultimately verifies multiple planet candidates in bulk and is unveiling a veritable bonanza of new worlds." These multiple-planet systems are fertile grounds for studying individual planets and the configuration of planetary neighbourhoods. This provides clues to planet formation.

SATURN, THE LORD OF THE RINGS

Big beautiful Saturn, complete with its astonishing set of rings. The Cassini Division is the black radial where astronomers believe a moon has cleared out the icy debris via its gravity. Image courtesy of NASA/JPL Cassini Imaging Team.

ByANDY FLEMING

If there is one celestial object that is both readily visible in even the worst light polluted skies, and yet full of the astronomical “wow” factor, it has to be Saturn, our solar system’s beautiful ringed gas giant planet.

For anyone new to telescopic observing, Saturn is usually an early and easy target. The planet has fascinated me for a long time, revealing an interesting bright disk when viewed through my 10x50 binoculars, but definite and tantalising “handles” or “ears” when viewed with some old 12x50s - very much in accordance with Galileo’s findings in the early seventeenth century. It yearns for greater magnification.

Saturn is like an old friend to me, both often gracing our skies and never failing to impress when other planets, like Mars, often fail. Having had an hour observing the Moon, I simply couldn’t wait any longer to observe Saturn with my 200mm Dobsonian. Like most people, when I first observed Saturn I was unprepared for the awesome views of the planet as revealed through a large, quality telescope with a sturdy mount.

CARL SAGAN & HIS LIFE IN THE COSMOS: A TRIBUTE

ByANDY FLEMING

It's incredible to think that it's more than fourteen years since the world lost a most remarkable astronomer, pioneer exobiologist and populariser of science - Carl Sagan.

A son of Jewish immigrants to the United States, Sagan was born in Brooklyn, New York, where he spent his childhood developing an interest in astronomy. A high achiever, he studied physics at the University of Chicago, gaining a master's degree in 1956, before being awarded a doctorate there in 1960 in astronomy and astrophysics. He then lectured at Harvard University until 1968, when a move to Cornell University in Ithaca, New York beckoned. In 1971 this became a full-time professorship that included the directorship of the Laboratory for Planetary Studies. He also took an increasing interest in pioneering exo-biology and publicising the Search for Extraterrestrial Intelligence (SETI). During this period, he also became an Associate Director of the Centre for Radio Physics and Space Research at Cornell, and later was instrumental in lecturing at Cornell in scepticism and critical thinking.

Such an academic career would have been amazing in itself, but Sagan had been heavily involved in the US space program since the 1950s -- including his celebrated briefings of the Apollo astronauts before their flights to the Moon. However, of utmost interest to this most talented of scientists was planetary science and the increasing number of NASA robotic missions to neighbouring planets in the solar system.

BLUES FOR A RED PLANET

Many scientists think that the Ancient Martian Ocean Would Have Been Salty ‘Dead Sea’.

ByANDY FLEMING

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?

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 speculatively, 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. 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 ancient 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 length 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 with Mars 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.