Interview with Dr Clem Pryke
Dr Clem Pryke, of the University of Minnesota, is one of the principal investigators for the BICEP2 experiment, which recently found evidence of gravitational waves in the very early Universe by analysing the cosmic microwave background. In this interview, Dr Pryke talks about how the discovery supports the theory of cosmic inflation and whether there might yet be a twist in the tale of the detection of gravitational waves.
The Night Sky
Ian Morison tells us what we can see in the northern hemisphere night sky during July 2014.
The star Arcturus, in the constellation of Boötes, is setting in the west around midnight. The circlet of stars called Corona Borealis is up to its left, with Hercules higher up still. Continuing around the sky, the bright star Vega appears in Lyra the Lyre. Deneb, in Cygnus the Swan, is up to its left, and the five brightest stars of Cygnus can be seen to form a cross known as the Northern Cross. The lowest and faintest of these, Albireo, is revealed to be a double star of blue and gold colours when observed with a telescope. Coming down through the constellations of Vulpecula and Sagitta, we reach Aquila the Eagle and its bright star, Altair. The three stars of Vega, Deneb and Altair comprise the Summer Triangle. Below this, in the constellations of Serpens Caput, Ophiuchus and Serpens Cauda, Sagittarius is lying in the south. It contains the asterism of the Teapot, which is home to many star clusters and nebulae. The tiny constellation of Delphinus the Dolphin is to the lower left of Cygnus and Lyra.
- Jupiter reaches conjunction (behind the Sun in the sky) on the 24th, and so is only visible for the first week of July, low in the west.
- Saturn is in Libra, near the wide double star Alpha Librae. It dims from +0.4 to +0.5 during the month, and reverses direction as its retrograde (westward) motion ends on the 21st. The rings are at 21° to the line of sight, but the planet remains at a low elevation for northern hemisphere observers.
- Mercury appears before dawn, lying to the lower left of Venus for much of the month. It reaches western elongation (furthest from the Sun in the sky) on the 12th, when it has a magnitude of +0.4 and a presents a half-full disc. It appears lower in the east at dawn later in July, but brightens to magnitude -1.4 by month's end.
- Mars lies close to the star Spica, in Virgo, and is just 1.3° away on the 13th. It shrinks from 9.5 to 7.9" in angular diameter during July, and dims from magnitude 0 to +0.4. It is already low in the west at nightfall, but larger surface features, such as Syrtis Major, may be spotted through a telescope.
- Venus rises in the east-north-east at morning twilight, and is 20° above the horizon at sunrise. It decreases in angular size from 12 to 11" over the month as it moves away from the Sun, but the illumination of its gibbous disc increases from 85 to 92% over the same period, so its brightness drops only slightly, from magnitude -0.9 to -0.8. Venus is close to Aldebaran, in Taurus, in the first few days of the month.
- Saturn is still nice to observe this month. It can be found by following the Plough's handle down past Arcturus to the bright white star Spica, then looking for the slightly brighter, yellower object to its lower left.
- The globular cluster M13 is high in the sky this month. It is two-thirds of the way up the right-hand side of the Keystone asterism in Hercules, appearing as a fuzzy glow in binoculars and a spherical concentration of stars in a telescope. Nearby, the multiple star system Epsilon Lyrae is to the left of Vega in Lyra. It looks like a double star in binoculars, but a telescope shows a pair of doubles, giving rise to the nickname of the Double Double.
- Noctilucent clouds may be observed early in the month. They can be seen in the north during deep twilight and are 80 kilometres above the Earth, allowing them to be illuminated by the already-set Sun while lower clouds are in shadow.
- Mars lies between Spica and a first-quarter Moon in the south-west after sunset on the 5th.
- The two brightest asteroids, Vesta and Ceres, can be found using binoculars after sunset on the 5th and 6th. They are only 10' apart in Virgo and have magnitudes of +7.2 and +8.5 respectively, the former being smaller but also closer and more reflective.
- Saturn and a gibbous Moon are close together an hour after sunset on the 7th.
- Venus is 4.5° to the lower-left of a thin crescent Moon before dawn on the 24th, with Mercury 8° further to the lower-left, near the eastern horizon.
Odds and Ends
NASA launched the Orbiting Carbon Observatory-2 (OCO-2) in early July, to take a first look at the distribution of carbon dioxide in the Earth's atmosphere. Making 100,000 spectroscopic measurements each day, OCO-2 will map the areas where carbon dioxide is released into, and drawn from, our atmosphere by natural and man-made processes. The mission will improve our understanding of the effects of climate change on our planet, and will operate as part of a synchronised fleet of instruments called the A-Train, monitoring the health of the terrestrial environment.
NASA's Dawn spacecraft has been used to find evidence that dark material on the asteroid Vesta was left by small meteorite impacts. The presence of minerals of the Serpentine group, which can only exist at temperatures below 400 degrees celsius, argued against volcanic eruptions or larger impacts as the source of Vesta's craters.
At the 2014 National Astronomy Meeting in Portsmouth, UK, Professor Martin Barstow from the University of Leicester gave a talk calling on governments and space agencies to support a new space telescope project called the Advanced Technologies Large-Aperture Space Telescope (ATLAST). The telescope would have a primary mirror with a diameter of 20 metres, making it not only the largest ultraviolet/optical/near-infrared telescope in space but also larger than any ground-based optical or infrared telescope currently in existence. ATLAST is currently only in the concept stage with a plan for launch in 2030.
|Interview:||Dr Clem Pryke and Chris Wallis|
|Night sky:||Ian Morison|
|Presenters:||George Bendo, Cristina Ilie and Mark Purver|
|Editors:||Indy Leclercq and Mark Purver|
|Segment Voice:||Iain McDonald|
|Website:||Indy Leclercq and Stuart Lowe|
|Cover art:||Composite image of Vesta, the second-largest asteroid in our Solar System, as seen by NASA's Dawn spacecraft. CREDIT: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA|