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. Read more about it here.
• 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 fro 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.
  • More discoveries made using Arecibo can be found here.