Wednesday, August 3, 2016

NASA Expects Fireball Outbursts From Perseid Meteor Shower In August 2016

The 2016 Perseid Meteor Shower is visible for about two weeks before and after its peak which occurs during the early morning hours of August 12, 2016.  The summer's best meteor shower will be more spectacular this year because NASA astronomers are predicting twice the normal amount of meteors.

The Perseid Meteor Shower produces more fireballs than any other meteor shower, according to Bill Cooke of NASA's Meteoroid Environment Office.  A fireball is a very bright meteor, at least as bright as the planets Jupiter or Venus.  They can be seen on any given night as random meteoroids strike Earth's upper atmosphere. One fireball every few hours is not unusual.  Fireballs become more numerous, however, when Earth is passing through the debris stream of a comet.  That’s what will happen this month.

Cooke thinks the Perseids are rich in fireballs because of the size of the parent comet. Comet Swift-Tuttle has a huge nucleus--about 26 km in diameter," said Cooke. "Most other comets are much smaller, with nuclei only a few kilometers across. As a result, Comet Swift-Tuttle produces a large number of meteoroids, many of which are large enough to produce fireballs."

Perseid Meteor Shower Outburst In 2016

“Forecasters are predicting a Perseid outburst this year with double normal rates on the night of Aug. 11-12,” said Cooke. “Under perfect conditions, rates could soar to 200 meteors per hour.”

An outburst is a meteor shower with more meteors than usual. The last Perseid outburst occurred in 2009.

Every Perseid meteor is a tiny piece of the comet that orbits the sun every 133 years. Each swing through the inner solar system can leave trillions of small particles in its wake. When Earth crosses paths with Swift-Tuttle’s debris, specks of comet-stuff hit Earth’s atmosphere and disintegrate in flashes of light. These meteors are called Perseids because they seem to fly out of the constellation Perseus.

Most years, Earth might graze the edge of Swift-Tuttle’s debris stream, where there’s less activity. Occasionally, though, Jupiter’s gravity tugs the huge network of dust trails closer, and Earth plows through closer to the middle, where there’s more material.

This may be one of those years. Experts at NASA and elsewhere agree that three or more streams are on a collision course with Earth.

“Here’s something to think about. The meteors you’ll see this year are from comet flybys that occurred hundreds if not thousands of years ago,” said Cooke. “And they’ve traveled billions of miles before their kamikaze run into Earth’s atmosphere.”

2016 Perseid Meteor Shower: Where To Watch

The Perseids meteor shower will be visible almost all over the world - but will be best seen in the northern hemisphere.   A major determining factor on where a good place is to watch the Perseids meteor shower is local cloud cover and artificial light pollution. Lie on your back and look straight up. Allow about 45 minutes for your eyes to adjust to the dark.

2016 Perseid Meteor Shower: Where To Look

You can tell if a meteor belongs to a particular shower by tracing back its path to see if it originates near a specific point in the sky, called the radiant. The constellation in which the radiant is located gives the shower its name, and in this case, Perseids appear to come from a point in the constellation Perseus. Photo credit: NASA/JPL

2016 Perseid Meteor Shower: When To Watch

The best way to see the Perseids is to go outside between midnight and dawn on the morning of Aug. 12th. Although the moon is bright enough to blot out some of the meteors, it sets around 1 a.m. on the morning of August 12th, just at the peak time for the best Perseid viewing. While skywatchers will see the most meteors after moonset on Friday morning August 12th, the nights on either side of the peak have elevated rates too.

TOP PHOTO: An outburst of Perseid meteors lights up the sky in August 2009 in this time-lapse image. Stargazers expect a similar outburst during next week’s Perseid meteor shower, which will be visible overnight on Aug. 11 and 12. Photo Credits: NASA/JPL