Astronomy news

Hayabasa2 Probe

At https://phys.org/news/2019-07-japan-hayabasa2-probe-touchdown-asteroid.html .... and https://phys.org/news/2019-07-japan-asteroid-probe-hayabasa2-touchdown.html ... the Japanese Hayabasa 2 space probe made a 'perfect' touchdown on asteroid Ryugu and has collected samples from beneath the surface for laboratory analysis. An incredible technological feat but we shall have to wait for the results of the analyses.

Solar cycle 25

At http://spaceweather.com (2nd July 2019) ... the face of the Sun has been blank for several days but on Sunday a small sun spot appeared, the beginnings of solar cycle 25. The solar minimum is still ongoing but the sun spot is a sign that it is coming to an end. The polarity of the sun spot is affected by its magnetic field. Sun spots switch polarity from one solar cycle to the next one, which is how they can tell it is cycle 25.

Another meteor making noises

A small asteroid exploded in the atmosphere near Peurto Rico on June 22nd - see http://spaceweather.com (June 25th 2019). It occurred in broad daylight and the airwaves produced were detected by the Nuclear Test Ban Treaty Organisanization's infra red station in Bemuda. The explosion was coincident with a cosmic body several metres across and according to NASA such meteors, on average, happen at least once a year. It had the blast energy of between 3 and 5 kilotons of TNT.

Rings around Uranus

At https://phys.org/news/2019-06-astronomers-uranus.html ... astronomers see a warm glow emanating from the rings of Uranus - via the ALMA telescope array. Its most prominent ring is composed of golf ball size rocks and larger - and there are 13 rings in all.

At https://phys.org/news/2019-06-stars-photons-revolutionize-space-flight.html ... star photons may revolutionise space flight - the solar sail. It has no engine, uses no fuel, and has no solar panels. Instead, it harnesses the momentum of light energy (photons). Will it work?

The Maunder Minimum

At https://malagabay.wordpress.com/2019/06/17/maunder-minimum-and-the-comet... ... the Maunder Minimum (a very cold episode supposedly associated with a lack of sun spots) is under scrutiny by Tim Cullen. A volcanic event is visible in Alpine ice cores. However, cometary dust may have prolonged the Minimum - the takeway part of the post. The Great Comet of 1744, naked eye visible for several months, displayed an unusual feature - a fan of six tails. This has vexed astronomers as to why it might have happened.

Volcanic Dome on Ceres

At https://phys.org/news/2019-06-gravitational-dawn-dome-ceres-volcanic.html ... gravitational data beamed back by the Dawn mission suggests the dome on Ceres is a mud volcano - a mix of salty brine and solids. Volcanism is perhaps the key to understanding this but it was thought, until now, that volcanism was absent on such a small planet as Ceres (or is it a large asteroid). Not only that but they think the dome may be of recent date. It is in fact a mountain, or volcano, 4km in height and 17 km across.

Rhythm of the Planets

This story is at https://tallbloke.wordpress.com/2019/05/29/the-sun-follows-the-rhythm-of... ... Tall Bloke was especially interested in this new research as he, and colleagues, have been saying something similar for a long time and have generally been ignored. The German study corroborates the influence of planetary tidal forces on solar activity. They claim the tidal influences of Jupiter, Venus and the Earth affect the solar magnetic field thus governing the solar eleven year cycle.

Water

Yesterday we had a post on the idea a collision with a proto planet led to the formation of the Moon and provided the Earth with abundant water. Today, at www.jpl.nasa.gov/news/news.php?feature=7409 ... we are told NASAs SOFIA mission has found evidence that water in some comets is similar to water in Earth's oceans. This reinvigorates the theory that comets played a major role in delivery of water to Earth, many moons ago. SOFIA = the Stratospheric Observatory for Infrared Astronomy, which made observations of Comet Wirkonen back in December of 2018.

Water on Earth

William sent in this link - https://phys.org/news/2019-05-formation-moon-brought-earth.html ... the formation of the Moon brought water to Earth, the latest idea on why there is so much water on earth compared to the other planets. The new theory involves a collision of the Earth with a proto planet - which is called Theia. This is the same collision that has been proposed as causing the actualy creation of the Moon - but with a difference. It brought lots of water to Earth rather than just gouge a great big hole out of the planet in which the bits reassembled themselves into the Moon.

Moon Differences

Sent in by William - go to https://phys.org/news/2019-05-giant-impact-difference-moon-hemispheres.html ... a giant impact caused the differences between the two hemispheres of the Moon. The topographic evidence, crustal thicknesses, the thorian distribution, etc, show a dramatic difference between the nearside and the farside. The farside is heavily cratered but the nearside, the earth facing side of the Moon, has lower lying open basins.