In Space News:
The Chinese Chang’e 5 lunar mission returned to Earth from the Moon on Dec 17 bringing back near 2kg of lunar material for examination.
Space X’s starship SN8 exploded in a test on Dec 10th.
In the ‘great conjunction’, Jupiter, Saturn, and Earth aligned visibly for the first time in 800 years.
On to the Arecibo observatory:
The construction of Arecibo observatory in a natural sinkhole in Puerto Rico in 1960. It was proposed by physicist Willam E Gordon at Cornell University to study the ionosphere of the Earth.
Unlike other radion telescopes, along with receiving radio signals from the Universe, Arecibo has the capability of sending out a radio signal which has been very useful.
Unfortunately due to various natural (most recently Hurricane Maria in Sept 2017) and financial strains, prevented regular, required maintenance.
The lack of these required maintenances led to the snapping of cables that houses a 900-tonne structure with equipment. The timeline of the decommissioning:
First Cable Snap: Nov 6
Second Cable Snap: Nov 18
Decommission: Nov 19th
900-tonne housing fell: Dec 1
Some of the notable discoveries by Arecibo observatory are:
Arecibo discovered that the rotation rate of mercury is 59 days to better understand the orbit of Mercury around the sun.
Arecibo discovered the first every binary pulsar and studying it confirmed predictions of general relativity. This discovery won the Nobel Prize in Physics in 1993.
Arecibo’s radar allowed it to send signals towards the Hercules star cluster in search of extraterrestrial intelligence.
Arecibo observatory also discovered the first every exoplanet around a pulsar.