Fireball over Lake Michigan.

The American Meteor Society has received reports of a bright fireball meteor being seen over the Lake Michigan, slightly before 11.50 pm on Friday 10 May 2019 Central Time (about 4.50 am on Saturday 11 May GMT). The meteor was seen from Illinois, Indiana, Michigan, Ohio, Pennsylvania, and Wisconsin, with the majority of the reports coming from Illinois. 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. 

The 10 May 2019 Lake Michigan Meteor, seen from Elgin, Illinois. Bluff City Jeff/Twitter.

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. This object appeared to move north-to-south, passing over Lake Michigan and part of Indiana, where it disappeared. 

 Map showing areas where sightings of the meteor were reported, and the apparent path of the object (blue arrow). American Meteor Society.

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.

 

Witness reports can help astronomers to understand these events. If you witness a fireball-type meteor over the US you can report it to the American Meteor Society here. 

 

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Fireball meteor over Michigan causes Earthquake.

The American Meteor Society has received reports of a bright fireball meteor being seen over the Great Lakes region of North America at about 8.10 am local time (about 1.10 am GMT) on Tuesday 16 January 2018. People have reported seeing the event from Iowa, Illinois, Indiana, Ohio, Michigan, Pennsylvania, and Ontario (Canada), with the majority of sightings coming from Michgan and Ohio. 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. The object was seen moving from northeast  to southwest over the eastern part of the state. 

The 16 January 2018 meteor seen from Michigan. Zack Lawler/WWMT.

The Object has been calculated to have been moving from east to west over the southeastern part of Michigan, and produced a loud booming noise that was recorded as a Magnitude 2.0 Earthquake by the United States Geological Survey. This has been interpretted as being indicative of a large, slow moving (about 45 000 km per hour) object, and it is thought likely that a number of meteorites will have reached the ground.

Map showing areas in southeast Michigan where sightings of the meteor were reported, and the route of the object (blue arrow). American Meteor Society.

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).

 

 The recorded epicenter of the 16 January Michigan fireball-induced Earthquake (gold star) and areas where it was felt (blue and white squares). USGS.

 

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.

 

Witness reports can help astronomers to understand these events. If you witness a fireball-type meteor over the UK you can report it to the American Meteor Society here.

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Algal Bloom covers much of western Lake Erie.

Much of the western end of Lake Erie in North America is currently covered by an Algal Bloom, which estimated to cover about 1800 square kilometres of the lake's surface by the end of September 2017. This is the latest in a series of such late-summer blooms that have been recorded since the early 2000s, causing problems for communities and wildlife around the lake, as the Algae are both toxic and cause problems by absorbing oxygen from the water, causing other aquatic organisms to asphyxiate. These Blooms are thought to be the result of eutrophication (excess nutrient loading) caused by excessive use of fertilisers on farmland in the basins of rivers which drain into the lake. Authorities in the US have responded to these Blooms by introducing stringent rules on fertiliser use in these river basins, yet the Blooms have continued to grow larger each year, causing many people to question whether fertiliser use is truly the cause of the problem.

MODIS/Terra satellite image of an Algal Bloom on Lake Erie taken on 24 September 2017. NASA/Earth Observatory.

In a paper published in the Journal of Great Lakes Research on 12 May 2017, Jeff Ho of the Department of Civil & Environmental Engineering at Stanford University and the Department of Global Ecology at the Carnegie Institution for Science, and Anna Michalak, also of the Department of Global Ecology at the Carnegie Institution for Science, present the results of a study in which they combine data from the current MERIS spectroradiometer on the European Space Agency's Envisat satellite and MODIS spectroradiometer on NASA's Terra satellite with data collected by the historic Landsat 5 satellite to produce a longer-term analysis of Algal Blooms on Lake Erie.

The combination of the Terra, Envist and Landsat 5 data enabled Ho and Michalak to build up a series of images of the lake dating back to 1984. In addition, since different types of Algae refract light at different wavelengths, it was possible to determine the makeup of these Blooms.

Ho and Michalak found that Blooms were present in the earliest images, with the summers of 1984-87 dominated by Diatom and Chlorophyte (Green Algae) growth. In 1988-92 there was a significant decrease in the overall biomass of the Blooms, with the Diatoms being replaced incrementally by Chrysophyte (Golden) Algae, which are largely inedible to Zooplankton, beginning a breakdown in food-chains in the lake. From 1993 to 1996 the Chlorophyte component of the Blooms was progressively replaced by Cyanobacteria of the genus Microcystis, which produce a range of harmful toxins, further excluding larger organisms from the lake. These Microcystis-dominated Blooms grew in size, recovering the 1984-87 biomass over the period 1997-2000, then increasing further in size from 2000 onwards, eventually producing the large and alarming Blooms of recent years.

Microcystis aeruginosa, a highly toxic species of Cyanobacteria associated with harmful Algal Blooms. Sergei Shalygin/AlgaeBase.

Ho and Michalak suggest that while excess nutrients from farm runoff may have been the original cause of the crisis, triggering a change in the makeup of the Blooms, the increase in the size of the Blooms is a result of this change, with an explosion in Bloom size occurring after the Blooms became dominated by species which excluded secondary consumers. Once this occurred the original cycle, in which nutrients are observed by Algae, then passed to secondary consumers (Zooplankton and small Fish), then larger Fish, and eventually taken out the lake by terrestrial predators (Humans, Birds, etc.), with one in which Algae died and sank to the bottom, where they decompose and release nutrients back into the lake, fuelling larger Blooms each year.

Ho and Michalak still believe that reducing the amount of nutrient runoff reaching the lake is the key to solving the problem, but that this will now take much longer to accomplish, as rather than relying on food chains to remove the excess nutrients, it will now be necessary to wait for them to be washed out via the River Niagara or be incorporated into permanent sediments at the bottom of the lake.

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Fireball over the Eastern Great Lakes region.

The American Meteor Society has received reports of a bright fireball meteor being seen over parts of the Eastern Great Lakes region slightly after 10.35 pm on Tuesday 4 October 2016 Eastern Daylight Time (slightly after 2.35 am on Wednesday 5 October GMT). The majority of the reports came from the Canadian state of Ontario, but sightings were also reported from New York, Pennsylvania, Maryland, New Jersey, Washington DC, Michigan, West Virginia, Delaware, Massachusetts, Virginia and Québec. 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.

 Animation of the 4 October fireball made using still photographs taken at the University of Toronto Scarborough Observatory. American Meteor Society.

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. It is possible that this object will have produced meteorites that reached the surface (an object visible in the sky is a meteor, a rock that falls from the sky and can be physically held and examined is a meteorite).

Witness reports can help astronomers to understand these events. If you witnessed this fireball you can report it to the American Meteor Society here.

See also...

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