Bright fireball meteor over northeast China.

Witnesses across northeastern China have reported witnessing a fireball meteor slightly after 0.15 am Beijing Time  on Friday 11 October 2019 (slightly after 4.15 pm on Thursday 10 October GMT). The majority of sightings came from the city of Songyuan in Jilin Province, but with many sightings elsewhere in Jilin and Heilongjiang provinces. A fireball is defined as a meteor (shooting star) brighter than the planet Venus. These are typically caused by pieces of rock burning up in the atmosphere, but can be the result of man-made space-junk burning up on re-entry. 

Dashboard camera image of a fireball over northeastern China on 11 October 2019, seen from Jilin Province. CCTV.

Objects of this size probably enter the Earth's atmosphere several times a year, though unless they do so over populated areas they are unlikely to be noticed. They are officially described as fireballs if they produce a light brighter than the planet Venus. The brightness of a meteor is caused by friction with the Earth's atmosphere, which is typically far greater than that caused by simple falling, due to the initial trajectory of the object. Such objects typically eventually explode in an airburst called by the friction, causing them to vanish as an luminous object. However this is not the end of the story as such explosions result in the production of a number of smaller objects, which fall to the ground under the influence of gravity (which does not cause the luminescence associated with friction-induced heating).

 

These 'dark objects' do not continue along the path of the original bolide, but neither do they fall directly to the ground, but rather follow a course determined by the atmospheric currents (winds) through which the objects pass. Scientists are able to calculate potential trajectories for hypothetical dark objects derived from meteors using data from weather monitoring services.

 

See also...

 

Follow Sciency Thoughts on Facebook.

Second explosion at Jilin mine kills at least seven more workers.

A second explosion at the Babao Coal Mine in Baishan, Jilin Province, has killed a further seven mineworkers. The mine was closed on Friday 29 March 2013, after a gas explosion which led to 29 fatalities, but on the morning of Monday 1 April a manager at the mine responded to a report of smoke issuing from the pit by sending a team of 21 workers to extinguish the blaze. This team was reportedly on a platform 300-400 m beneath the surface when a second gas explosion occured. The bodies of seven miners have been recovered, and four have been rescued with minor injuries; the reamining ten are still missing.

 

Relatives of trapped workers at the Babao Mine waiting for news. Zhang Yao/China News Service.

The mine is operated by the state owned Tonghua Mining Group, which is generally considered to have a good safety record, compared to other companies in the country. The mine had been ordered to close pending an investigation by authorities, and permission for the mineworkers to re-enter the pit had not been granted. Police have now reportedly detained a number of senior managers at the mine, who can be held criminally responsible under Chinese law. 

See also Twenty-eight miners reported dead after explosion at Chinese coal mine, 83 feared dead after Tibetan landslip, Seven workers killed by mine explosion in Hunan Province, China, Miners trapped by flooding at Qielichong Coal Mine in Hunan Province, China and At least 21 miners killed in mining disaster in Yunnan Province, China.

Follow Sciency Thoughts on Facebook.

 

Twenty-eight miners reported dead after explosion at Chinese coal mine.

Twenty-eight miners are reported to have died in a gas explosion at the Babao Coal Mine in Jilin Province, in the far northeast of China, at 10.40 pm local time (1.40 pm GMT) on Friday 29 March 2013. A further 13 workers suffered miner injuries; rescuers are not looking for any further people.

The location of the Babao Coal Mine. Google Maps.

Gas explosions in coal mines are an unpleasantly common event. Coal is formed by the compression and heating of plant matter in deeply buried sediments. The remaining coal is mostly carbon, with other elements that  were present in the original material being squeezed out by the pressure. However if these are not able to escape they will be trapped as pockets of gas, typically a mix of methane, hydrogen, carbon monoxide, water vapor and volatile hydrocarbons.

China gains 70% of its energy from coal-burning power stations, which places the country under great pressure to maintain coal supplies. This has led to a poor safety record within the mining sector, particularly in the private sector, where there is a culture of seeking quick profits in poorly regulated (and often officially non-existent) mines. State owned mines are often thought to be better regulated, but still compare badly to mines in other parts of the world; the Babao Coal Mine is run by the state-owned Tonghua Mining Group.

See also 83 feared dead after Tibetan landslip, Polish miners rescued after Earthquake, Seven workers killed by mine explosion in Hunan Province, China, Miners trapped by flooding at Qielichong Coal Mine in Hunan Province, China and At least 21 miners killed in mining disaster in Yunnan Province, China.

Follow Sciency Thoughts on Facebook.