Carl Sagan examines our planet's place in the universe by leading us on a journey from Earth to Deep Space. Carl Sagan opens the program with a description of the cosmos and a "Spaceship of the Imagination" (shaped like a dandelion seed).
Image credit: PBS
The ship journeys through the universe's hundred billion galaxies, the Local Group, the Andromeda Galaxy, the Milky Way, the Orion Nebula, our Solar System, and finally the planet Earth. Eratosthenes' successful calculation of the circumference of Earth leads to a description of the ancient Library of Alexandria. Finally, the "Ages of Science" are described, before pulling back to the full span of the Cosmic Calendar. Note: the revised version of the series adds a two-minute introduction by Ann Druyan to this episode, in which she discusses some of the changes that occurred in the years after its broadcast.
The biggest explosion seen in the universe has been found. This record-breaking, gargantuan eruption came from a black hole in a distant galaxy cluster hundreds of millions of light years away.
Credit: Chandra X-ray Observatory
Astronomers made this record-breaking discovery using X-ray data from NASA's Chandra X-ray Observatory and ESA's XMM-Newton, and radio data from the Murchison Widefield Array in Australia and the Giant Metrewave Radio Telescope in India.
The unrivaled outburst was detected in the Ophiuchus galaxy cluster, which is about 390 million light years from Earth. Galaxy clusters are the largest structures in the Universe held together by gravity, containing thousands of individual galaxies, dark matter, and hot gas.
Chandra X-ray Observatory: A Quick Look at the Biggest Explosion Ever Seen in the Universe
In the center of the Ophiuchus cluster, there is a large galaxy that contains a supermassive black hole. Researchers have traced the likely source of this gigantic eruption to this black hole.
Although black holes are famous for pulling material toward them, they often expel prodigious amounts of material and energy. This happens when matter falling toward the black hole is redirected into jets, or beams, that blast outward into space and slam into any surrounding material.
Chandra X-ray Observatory: A Tour of the Biggest Explosion Ever Seen in the Universe
Astronomers needed to combine the X-ray information along with the radio data in order to clinch this finding. They discovered that a cavity in the hot gas, first seen in Chandra data in 2016, was filled almost perfectly with radio emission created by electrons that had been accelerated to nearly the speed of light. This allowed them to confirm that an explosion of unprecedented size took place in Ophiuchus.
The amount of energy required to create the cavity in Ophiuchus is about five times greater than the previous record holder, MS 0735+74, and hundreds and thousands of times greater than typical clusters.
The black hole eruption must have finished because the researchers do not see any evidence for current jets in the radio data. This shutdown can be explained by the Chandra data, which show that the densest and coolest gas seen in X-rays is currently located at a different position from the central galaxy. If this gas shifted away from the galaxy it will have deprived the black hole of fuel for its growth, turning off the jets.
While much has been learned about the galaxy cluster Ophiuchus through X-ray and radio telescopes, more data will be needed to answer the many remaining questions this object poses.
A plane broke into pieces after skidding off an airport runway in Istanbul, Turkey. The Pegasus airplane was carrying 177 people and set off from Izmir. Emergency services took those who were injured to hospital and evacuated remaining passengers onboard. Authorities said the incident was a result of bad weather.
Miraculously nobody was killed in the landing, the Turkish transport minister said.
(AP) A plane flying into Istanbul's Sabiha Gokcen airport from Izmir skidded off the runway and crashed on Wednesday but there were no fatalities, Turkish Transport Minister Cahit Turhan said. The plane split into three pieces after what Mr Turhan called a rough landing. He added some passengers were injured.
A spokeswoman for Pegasus Airlines confirmed the crash but did not provide further details. Mr Turhan said the plane was carrying 171 passengers and six crew members from Turkey's western province of Izmir. Istanbul Governor Ali Yerlikaya said on Twitter that emergency response teams were working to evacuate the passengers.
Did this Airbus A330 have a mind of its own? Find out why the A330 operating Qantas Flight 72 suffered a pair of sudden uncommanded pitch-down maneuvers during a flight from Singapore to Perth in October 7, 2008. The plane crash-landed, but very fortunately there were no deaths. All 315 onboard survived, however, 119 were injured. The injuries included fractures, lacerations and spinal injuries -- to several of the passengers and crew. Fourteen people were airlifted to Perth for hospitalization, with 39 others also attending hospital. In all, one crew member and 11 passengers suffered serious injuries, while eight crew and 99 passengers suffered minor injuries.
On 7 October 2008 at 09:32 SST, Qantas Flight 72, with the afore-mentioned 315 people on board, departed Singapore on a scheduled flight to Perth, Western Australia. By 10:01, the aircraft had reached its cruising altitude of around 37,000 feet (11,000 m) and was maintaining a cruising speed of Mach 0.82.
The incident started at 12:40:26 WST, when one of the aircraft’s three air data inertial reference units (ADIRUs) started providing incorrect data to the flight computer. In response to the anomalous data, the autopilot disengaged automatically, and a few seconds later, the pilots received electronic messages on the aircraft's ECAM, warning them of an irregularity with the autopilot and inertial reference systems, and audible stall and overspeed warnings. During this time, the captain began to manually control the aircraft. The autopilot was then re-engaged and the aircraft started to return to the prior selected flight level. The autopilot was disengaged by the crew after about 15 seconds and would remain disengaged for the remainder of the flight.
At 12:42:27, the aircraft made a sudden, uncommanded pitch down manoeuvre, experiencing –0.8 g, reaching 8.4 degrees pitch down and rapidly descending 650 feet (200 m). Twenty seconds later, the pilots were able to return the aircraft to the assigned cruise flight level, FL370. At 12:45:08, the aircraft made a second uncommanded manoeuvre of a similar nature, this time causing an acceleration of +0.2 g, a 3.5 degree down angle, and a loss of altitude of 400 feet (120 m); the flight crew was able to re-establish the aircraft's assigned level flight 16 seconds later. Unrestrained (and even some restrained) passengers and crew were flung around the cabin or crushed by overhead luggage, as well as crashing with and through overhead compartment doors. The pilots stabilised the plane and declared a state of alert, which was later updated to mayday when the extent of injuries was relayed to the flight crew.
The Australian Transport Safety Bureau (ATSB) investigation found a fault with one of the aircraft's three air data inertial reference units (ADIRUs) and a previously unknown software design limitation of the Airbus A330's fly-by-wire flight control primary computer (FCPC).
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Image credit: PBS
