Snippets

Athena to Study Hot and Energetic Universe – suggested by David Kaplan

27 June 2014 – ESA has selected the Athena advanced telescope for high-energy astrophysics as its second ‘Large-class’ science mission.  The observatory will study the hot and energetic Universe and takes the ‘L2’ slot in ESA’s Cosmic Vision 2015–25 plan, with a launch foreseen in 2028.

By combining a large X-ray telescope with state-of-the-art scientific instruments, Athena will address key questions in astrophysics, including: how and why does ordinary matter assemble into the galaxies and galactic clusters that we see today? How do black holes grow and influence their surroundings?

Scientists believe that black holes lurk at the centre of almost all galaxies and that they play a fundamental role in their formation and evolution.  To investigate this connection, Athena will observe X-ray emission from very hot material just before it is swallowed by a black hole, measuring distortions due to gravitational light-bending and time-delay effects in this extreme environment. Athena will also be able to determine the spin of the black hole itself.

Athena’s powerful instruments will also allow unprecedented studies of a wide range of astronomical phenomena. These include distant gamma-ray bursts, the hot gas found in the space around clusters of galaxies, the magnetic interplay between exoplanets and their parent stars, Jupiter’s auroras and comets in our own Solar System.

“Athena will be a state-of-the-art observatory that will provide a significant leap forward in scientific capabilities compared with previous X-ray missions, and will address fundamental open questions in astrophysics,” says Alvaro Giménez, ESA’s Director of Science and Robotic Exploration. “Its selection ensures that Europe’s success in the field of X-ray astronomy is maintained far beyond the lifetime of our flagship observatory XMM-Newton.”

Now officially selected for L2, Athena now moves into a study phase. Once the mission design and costing have been completed, it will eventually be proposed for ‘adoption’ in around 2019, before the start of construction.

After launch, Athena will travel to its operational orbit around the gravitationally semi-stable location in space some 1.5 million kilometres beyond Earth as seen from the Sun – a position coincidentally known as L2. ESA’s Herschel, Planck and Gaia missions have also used L2 orbits.

We Are Part of the Rainbow – submitted by Michael Wright

Although rain and sunlight have been part of Earth’s environment for four billion years, coloured rainbows occurred quite recently with the appearance of animals possessing colour vision. Our visual world with its brightness and colours occurs within our skull. Nevertheless, by some feat of mental projection we think that our visual world coincides spatially with the external world.  Thus we confuse the neural rainbow with the external rainbow, and naively attribute the indescribable colours of the former to the latter.  Three centuries ago, Sir Isaac Newton, aware of this overpowering illusion, wrote: “The rays to speak properly are not coloured. In them there is nothing else than a certain power and disposition to stir up a sensation of this or that colour.”  Yet, even today, most people regard the cone cells of the retina as “colour receptors,” as if colours existed in the external world.  They speak of “the true colours of moonbows and nebulae revealed by time-exposure photographs,” unaware that they are attributing a unique property of the neural photograph in their brain to the external photograph in their hands, and subsequently to moonbows and nebulae in the sky.  The eye does not detect the colours of the rainbow; the brain creates them. We are part of the rainbow, its most beautiful part.

Excerpt from Rainbows and Some Other Sky Phenomenon by Roy Bishop, RASC Observers Handbook 2014.

Lost and Found in Space – suggested by David Kaplan

How would you like to reboot a long abandoned NASA spacecraft and collect useful data? A dream, you say.  Well this group of space enthusiasts did it.

An op-ed from the July 19, 2014 the New York edition of the NYTimes.

 

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