What's The Matter With Dark Matter?

ByJUDITH E BRAFFMAN-MILLER

Our bewitching sky at night is blazing with fiery luminous objects, such as stars and galaxies. However, most of the matter in our Universe is "dark"--or, more precisely, invisible--and scientists are "in the dark" about its alluring and mysterious nature--hence its name, "dark matter"! This bizarre substance is believed to be composed of exotic non-atomic particles that do not interact with light--which is why it is invisible. Although scientists are in the process of rapidly closing in on the elusive identity of this weird and abundant stuff, its nature is still an intriguing puzzle. Adding to the puzzle, astronomers recently found that the merging galaxy cluster, Abell 520, which is 2.4 billion light-years away from Earth, possesses a core of dark matter and searing-hot gas that should be pulling in, with its mighty gravitational grip, many more galaxies than it apparently is--and this discovery is challenging existing theories suggesting that the dark matter should be anchoring these galaxies like a gigantic wad of glue, preventing them from wandering away into Space!

Luminous objects, such as stars and galaxies, make up only a small percentage of our Universe. We are composed of starry-stuff. The stars cooked the atomic elements that compose our bodies deep in their nuclear-fusing hearts, before they blasted themselves to pieces when they ran out of nuclear fuel, seeding the entire Cosmos with the ingredients to enable life to develop, on our own planet and elsewhere. The so-called "ordinary" atoms that make up such objects as stars, galaxies, planets, moons, and people, represent only a tiny fraction of the mass and energy content of our Cosmos (E = mc squared).

But the glittering stars are only the delightfully beautiful frosting on a magnificent Cosmic cake! The gigantic, starlit galaxies and unimaginably enormous clusters and superclusters of galaxies, are all embedded within halos of the mysterious dark matter. The dark matter, though never observed directly, is thought to exist because it exerts gravitational effects on objects that can be seen--such as stars and galaxies--even though it is invisible. In fact, the only way that the dark matter is known to interact with "ordinary" matter is through the force of gravity.

The true identity of dark matter is still unknown. The strange and abundant stuff weaves immense, web-like filaments throughout Spacetime, and does not interact with any form of radiation. The starlit galaxies are strung-out throughout this strange web-like structure like glittering beads on an intertwining Cosmic necklace.

Skylights Bite Size 29 - June 2013 Night Sky Guide

By ANDY FLEMING

Full Moon in June is on the 23rd.  This superb photograph was taken just hours before such a full phase in delightfully clear skies over Nottingham. It features eye-catching bright rays extending from the prominent young crater Tycho in the Moon's southern hemisphere. The slightly colour enhanced image also brings out subtle shades of blue, a real characteristic of terrain with a high content of titanium oxide and iron. The blue lunar terrain on the right includes the dark flat expanse of the Sea of Tranquility and the Apollo 11 landing site. (Image courtesy of NASA).

Our night sky guide for June 2013. Highlights this month are Saturn, Venus, The Moon, and tiny planet Mercury.

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Skylights Bite Size 29 - June 2013 Night Sky Guide

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Skylights is featured on Solid Gold Sunday each Sunday afternoon at 1425h UTC on 102.4FM in Hartlepool/East Durham, UK and live around the world online at www.radiohartlepool.co.uk

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Show Notes and Transcript

June is the month of our summer solstice and it brings the shortest and most twilit nights of the year but also the best chance of spotting noctilucent clouds from Britain. These "night-shining" clouds appear as silvery or electric-blue wisps and ripples low down between the north west and north east during the night. Composed of ice crystals 80 kilometres above the Earth, they are high enough to see the Sun and reflect its light when normal clouds are in darkness.

Yellowish Saturn dims a little but remains conspicuous some fairly high in the south at nightfall, and below the star Arcturus in Bootes. With Spica in Virgo, to Saturn's right, the three objects form a distinctive tall "L" which topples into the south west during the evening. Look for Saturn above-right of the Moon on June 19 when a telescope should give stunning views of the planets and its rings.

Magnificent Venus blazes brightly but is very low in the north west as the night begins, and sets only an hour or so after sunset.

Mercury hovers near Venus although binoculars may be needed to glimpse it in Britain's bright twilight. If you’re going on holiday during June in southern Europe then this is the time to see the tiny planet’s best evening show of 2013.

The Moon is full on June 23rd just as it comes to its closest for the year. Although it is only slightly wider than usual, the effect appears amplified by the optical illusion that makes the Moon appear larger when near the horizon, as it remains as it transits our low southern sky overnight.

Jumping Jupiter! It's "Einstein's Planet"!

ByJUDITH BRAFFMAN-MILLER 

This artist's concept shows the huge, scorching-hot "Einstein's planet," formally known as Kepler-76b, orbiting its host star, which has been tidally distorted into a slight football shape (exaggerated here for effect). The planet was detected by David A. Aguilar (CfA)

The search for planets in orbit around stars other than our own Sun has proven to be a long and difficult quest, and their ultimate discovery almost a generation ago is certainly one of humanity's greatest achievements. The first extrasolar planet orbiting a star like our own Sun was detected back in 1995 and, now, almost twenty years later, astronomers have succeeded in spotting many, many more planets dwelling beyond our own Solar System than the eight familiar major planets circling within it. As technologies developed over the years, extrasolar planets were discovered by dedicated planet-hunters using a variety of new methods. In May 2013, astronomers announced that by using predictions of Albert Einstein's two Theories of Relativity, they had discovered an enormous alien planet circling a distant star--the new-found world was appropriately nicknamed "Einstein's Planet"!

Einstein's Planet is one of the most recent alien-worlds to be discovered out of a hefty batch of over 800--at last count. However, it was the first to be found using this new method. The planet, dubbed with the less colorful, official name of Kepler-76b, is huge. It is approximately 25% larger than our own Solar System's Jupiter and it weighs about twice as much--placing it within a class of extrasolar planets dubbed hot Jupiters. The enormous and very, very hot world dwells about 2,000 light-years from our planet in the constellation Cygnus.

The first extrasolar planet to be discovered around a Sun-like star almost twenty years ago was also a hot Jupiter, and it was detected by planet-hunters using the Doppler Shift Method, which favors the discovery of giant planets orbiting in fast, close orbits around their parent stars. Until this very first extrasolar planet was discovered, hot Jupiters were an unknown and unforeseen class of planet. Such strange beasts do not dwell in our Sun's own bewitching family of eight--the large gas-giant planets, such as our own Jupiter and the ringed planet, Saturn, haunt the outer regions of our Solar System. Because the Doppler Shift Method was the very first technique to be successfully used by planet-hunters in their search for alien worlds, and this technique favors the discovery of hot Jupiters, the first batch of extrasolar planets to be discovered were members of this strange class. However, as techniques have steadily improved, smaller planets that dwell in orbits more distant from their parent stars, have been detected-- and a few of these alien worlds are small enough to be almost Earth-analogs. These smaller extrasolar planets have mostly been detected by planet-hunters using the transit method, whereby an orbiting planet crosses the face of its parent star, causing an exquisitely small dimming.

"Einstein's Planet"!

The planet-hunters who spotted Kepler-76b, successfully utilized, for the first time, certain subtle effects predicted by Albert Einstein's two Theories of Relativity. Einstein's first theory, his Special Theory of Relativity (1905), describes a Spacetime that has frequently been compared to an artist's canvas. The artist paints lines and points on this wonderful canvas that displays all that has ever been, is now occurring, and ever will be. This canvas is the stage where the play is being performed, rather than the play itself. The great achievement uniting stage and play came a decade later when, in 1915, Einstein announced his revolutionary Theory of General Relativity. In this second theory, Spacetime becomes the star actor in this greatest of all plays. In this drama, Spacetime tells mass how to move, and mass tells Spacetime how to curve. Spacetime is as flexible as a trampoline onto which a child tosses a bowling ball--a marvelous bowling ball that represents a heavy massive object, such as a fiery star. The bowling ball's mass creates a dimple, or a well, on the fabric of the trampoline. If the child then tosses a handful of marbles onto that fantastic trampoline, they will travel along curved paths around the "star", just as if they were planets circling in their orbits around a real star. If the bowling ball, or star, is removed, the marbles will then travel along straight paths. The mass of the bowling ball, or star, warps the fabric of the trampoline, or Spacetime. Gravity is the dimpling of the fabric of Spacetime caused by the weight of a massive object. 

Skylights Bite Size 28 - NASA's Voyager Spacecraft

By ANDY FLEMING

It's August 20 1977 and the NASA/JPL Voyager 2 spacecraft launches atop a Titan IIIE/Centaur heavy lift booster from the NASA Kennedy Space Center at Cape Canaveral, Florida. It's trajectory, that encompassed the famed 'grand tour' of the planets of the outer solar system, their rings and moons was planned to exquisite levels of accuracy using the centuries-old Newtonian Laws of Motion and Universal Gravitation. Credit: NASA Marshall Space Flight Center (NASA-Marshall Spaceflight Centre).

We take a look at NASA's veteran spacecraft Voyagers 1 an 2 and their amazing tour of the outer solar system. Much of what we now know about the outer ice ginats Uranus and Neptune is due to the data sent back to the Earth by Voyager 2.

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Skylights Bite Size 28 - NASA's Voyager Spacecraft

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Skylights is featured on Solid Gold Sunday each Sunday afternoon at 1325h UTC on 102.4FM in Hartlepool/East Durham, UK and live around the world online at www.radiohartlepool.co.uk

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Show Notes and Transcript

The Voyager 2 spacecraft is a 700 kg space probe launched by NASA on August 20, 1977 to study the outer Solar System and eventually interstellar space.

It was actually launched before Voyager 1, but Voyager 1 moved faster and eventually passed it. It has been operating for over 35 years and the spacecraft still receives and transmits data via NASA’s Deep Space Network. At a distance of 124 AU (or Sun/Earth distances) or 18.5 billion kilometres from Earth it is one of the most distant manmade objects (along with Voyager 1, Pioneer 10 and Pioneer 11).

Voyager 2 is part of the Voyager program with its identical sister craft Voyager 1, and is in what NASA calls ‘extended mission’, tasked with locating and studying the boundaries of the Solar System, including the Kuiper belt, the heliosphere and interstellar space.

The primary mission ended on December 31, 1989 after Voyager 2 encountered the Jovian system in 1979, the Saturnian system in 1980, the Uranian system in 1986, and the Neptunian system in 1989. It is still the only spacecraft to have visited the two outer gas giant planets Uranus and Neptune on it’s so called ‘Grand Tour’ of the solar system.

Both Voyager probes contain a gold-plated copper record that contains recordings of the sounds and images representing the diversity of life and culture on Earth.  The sounds include the music of Chuck Berry along with a number of classical composers. Full instructions of how to play the disks are included.

As the spacecraft silently traverse interstellar space will another space-faring civilisation, perhaps millions of years in the future find them and wonder about the beings that made them?

Skylights Bite Size 27 - April 2013 Night Sky Guide

By ANDY FLEMING

The ringed world Saturn is looking particularly stunning at opposition this month. (Image courtesy, NASA/JPL).

Our night sky guide for April 2013. Highlights this month are Saturn, Venus, The Moon, The Pleiades and The Hyades.

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Skylights Bite Size 27 - April 2013 Night Sky Guide

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Skylights is featured on Solid Gold Sunday each Sunday afternoon at 1425h UTC on 102.4FM in Hartlepool/East Durham, UK and live around the world online at www.radiohartlepool.co.uk

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Show Notes and Transcript

Orion marches into the western evening twilight this month as Leo reaches the Greenwich meridian and the Plough stands overhead. Meanwhile, the glorious ringed world Saturn has just reached opposition; that is on opposite side to the Sun from the Earth.  It is now the sole planet on view during darkness as the others are unfortunately gathering in the Sun's glare at dusk.

Saturn is brighter than it has been for three years, and is at its closest to the Earth at a mere 1.3 billion kilometres distant! From low in the east at nightfall, it passes due south later in the night. It stands above-right of Virgo's leading star Spica, and creeps west during April towards the double star Porrima, whose components are so close together at present that we need a good telescope and perfect conditions to separate them. However, even a modest telescope reveals Saturn’s beautiful ring system which is currently tipped at nine degrees to the Earth.

The Moon lies to the right of Saturn on the evening of April 16th and below Spica on the following night. There will be splendid views of the earth-lit crescent Moon in the lower western sky at nightfall.  This beautiful glow on the part of the Moon unlit by the Sun is called ‘Earthshine’.

Look for the Moon between the Hyades and the Pleiades (or Seven Sisters) open clusters in the Constellation of Taurus the Bull tonight.  Without optical aid and with a dark sky, we might glimpse the instantaneous disappearance, or what astronomers call an occultation, of the fairly dim star 37 Tauri by the Moon. This will occur at around 8.05pm in Hartlepool.

Brilliant Venus hugs the eastern horizon in the pre-dawn and stands eight degrees (or approximately eight lunar diameters) below the Moon on April 30th when Mercury, Jupiter and Mars are still hidden in the twilight below and to Venus's left.