September Equinox Marks the Start of Fall 2022

Complemented by cooler temperatures and falling leaves, the September equinox marks the beginning of the fall season for the Northern Hemisphere. This year’s autumnal equinox (for the Northern Hemisphere) or spring equinox (for the Southern Hemisphere) occurs on Sept. 22 at 8:04 p.m. CDT.

An illustration of the March (spring) and September (fall or autumn) equinoxes.
An illustration of the March (spring) and September (fall or autumn) equinoxes. During the equinoxes, both hemispheres receive nearly equal amounts of daylight. (Image not to scale) Credits: NASA/GSFC/Genna Duberstein

During an equinox the Sun shines directly over the equator resulting in nearly equal amounts of day and night throughout the world – except for the North and South Pole where the Sun approximately straddles the horizon for the entire day, according to Alphonse Sterling, an astrophysicist at NASA’s Marshall Space Flight Center in Huntsville, Alabama. Following the autumnal equinox, the Sun gradually continues to rise later and set earlier in the Northern Hemisphere – making the days shorter and the nightfall longer. The opposite is true in the Southern Hemisphere where the days begin to last longer.

Seasons are caused by Earth’s tilted axis which always points in the same direction. As Earth orbits around the Sun, the angle of sunlight that the Northern and Southern Hemispheres receive is different. “On the June solstice (summer) in the Northern Hemisphere, sunlight is more direct, so it warms the ground more efficiently,” said Mitzi Adams an Assistant Manager in the Heliophysics and Planetary Science Branch at Marshall. “In the Southern Hemisphere, sunlight is less direct (winter), which means that the ground is not heated as easily.”

A visual aid to better understand how the Earth's tilted axis causes the different seasons throughout the year in the Northern and Southern Hemispheres.
A visual aid to better understand how the Earth’s tilted axis causes the different seasons throughout the year in the Northern and Southern Hemispheres. Credit: NASA/Space Place

Astronomical seasons are defined by the Earth’s journey around the Sun, while meteorological seasons are guided by annual temperature cycles. Meteorologists group the seasons into time periods that line up with the weather and monthly calendar:  December through February is winter, March through May is spring, June through August is summer, and September through November is fall. Astronomical seasons are marked by the equinoxes and solstices that each happen twice a year. Solstices are when the Sun appears to reach the lowest or highest point in the sky all year; they mark the beginning of summer or winter. Solstices are commonly referred to as the longest (summer solstice) or shortest (winter solstice) day of the year.

The September equinox is a time that welcomes Earthlings to a new season. To those in the Northern Hemisphere, enjoy the beginning of milder weather and say hello to early sunsets and late sunrises.

by Lane Figueroa

Jupiter to Reach Opposition, Closest Approach to Earth in 59 Years!

Stargazers can expect excellent views of Jupiter the entire night of Monday, Sept. 26 when the giant planet reaches opposition. From the viewpoint of Earth’s surface, opposition happens when an astronomical object rises in the east as the Sun sets in the west, placing the object and the Sun on opposite sides of Earth.

Jupiter’s opposition occurs every 13 months, making the planet appear larger and brighter than any other time of the year. But that’s not all. Jupiter will also make its closest approach to Earth since 1963 – almost six decades ago! This happens because Earth and Jupiter do not orbit the Sun in perfect circles – meaning the planets will pass each other at different distances throughout the year. Jupiter’s closest approach to Earth rarely coincides with opposition, which means this year’s views will be extraordinary. At its closest approach, Jupiter will be approximately 367 million miles in distance from Earth, about the same distance it was in 1963. The massive planet is approximately 600 million miles away from Earth at its farthest point.

Photo of Jupiter with Red Spot
This photo of Jupiter, taken from the Hubble Space Telescope on June 27, 2019, features the Great Red Spot, a storm the size of Earth that has been raging for hundreds of years. Credits: NASA, ESA, A. Simon (Goddard Space Flight Center), and M.H. Wong (University of California, Berkeley)

“With good binoculars, the banding (at least the central band) and three or four of the Galilean satellites (moons) should be visible,” said Adam Kobelski, a research astrophysicist at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “It’s important to remember that Galileo observed these moons with 17th century optics. One of the key needs will be a stable mount for whatever system you use.”

Kobelski recommends a larger telescope to see Jupiter’s Great Red Spot and bands in more detail; a 4 inch-or-larger telescope and some filters in the green to blue range would enhance the visibility of these features.

According to Kobelski, an ideal viewing location will be at a high elevation in a dark and dry area.

“The views should be great for a few days before and after Sept. 26,” Kobelski said. “So, take advantage of good weather on either side of this date to take in the sight. Outside of the Moon, it should be one of the (if not the) brightest objects in the night sky.”

As the Moon rose over the Wasatch Mountains near Salt Lake City on Feb. 27, 2019, the planet Jupiter could be seen, along with three of its largest moons.
As the Moon rose over the Wasatch Mountains near Salt Lake City on Feb. 27, 2019, the planet Jupiter could be seen, along with three of its largest moons. Stargazers should have a similar view during Jupiter in Opposition on Monday, Sept. 26. Credits: NASA/Bill Dunford

Jupiter has 53 named moons, but scientists believe that 79 moons have been detected in total. The four largest moons, Io, Europa, Ganymede, and Callisto, are called the Galilean satellites. They are named after the man who first observed them in 1610, Galileo Galilei. In binoculars or a telescope, the Galilean satellites should appear as bright dots on either side of Jupiter during opposition.

NASA’s Juno spacecraft, which has been orbiting Jupiter for six years, is dedicated to exploring the planet and its moons. Juno began its journey in 2011 and reached Jupiter five years later. Since 2016, the spacecraft has provided incredible images and data about Jupiter’s lively atmosphere, interior structures, internal magnetic field, and magnetosphere.

Scientists believe studying Jupiter can lead to breakthrough discoveries about the formation of the solar system. Juno’s mission was recently extended until 2025 or until the end of the spacecraft’s life. Learn more about Juno.

The next major project for Jupiter exploration is the Europa Clipper. This spacecraft will explore Jupiter’s iconic moon, Europa, which is known for its icy shell and vast ocean that lies beneath its surface. NASA scientists aim to find whether Europa has conditions able to sustain life.  Europa Clipper’s targeted launch is currently scheduled for no earlier than October 2024.

Learn more about the giant planet. And if you want to know what else is happening in the sky for September, check out  Jet Propulsion Laboratory’s latest “What’s Up” video:

by Lane Figueroa

Fireball lights up the sky over Salt Lake City

A bright meteor flew through the skies over northern Utah on Saturday morning, later raining down meteorites over the Great Salt Lake.

Residents of the Salt Lake City area were startled by loud booms at 8:30 a.m. MDT on Saturday, Aug. 13, 2022. Eyewitnesses saw a fireball in the sky, 16 times brighter than the full Moon.

GOES 17 Geostationary Lightning Mapper detection of the Aug. 13, 2022, fireball over northern Utah.
GOES 17 Geostationary Lightning Mapper detection of the Aug. 13, 2022, fireball over northern Utah. Credits: NOAA

Approximately 22,000 miles out in space, NOAA’s Geostationary Lightning Mappers (GLM) onboard the Geostationary Operational Environmental Satellites (GOES) 17 and 18 detected the meteor, which was first seen 50 miles over West Valley City. However, it is difficult to pinpoint its exact trajectory.

“Daytime fireballs are very tough to analyze,” said Bill Cooke, lead of NASA’s Meteoroid Environments Office at Marshall Space Flight Center in Huntsville, Alabama. “There are few eyewitness sightings of the fireball and videos posted on social media are difficult to calibrate without stars in the background.”

The meteor was first seen 50 miles over West Valley City, Utah, moving to the northwest at 39,000 miles per hour. The object broke apart above the eastern shore of the Great Salt Lake.
The meteor was first seen 50 miles over West Valley City, Utah, moving to the northwest at 39,000 miles per hour. The object broke apart above the eastern shore of the Great Salt Lake. Credits: NASA

After traveling northwest at 39,000 miles per hour, the object – a piece of an asteroid about 2 feet across – broke apart above the eastern shore of the lake. “One meteorite has been recovered from the lake shore,” said Cooke. “There are probably more, but I would expect the vast majority fell into the water.”

NASA studies meteoroid environments in space to protect astronauts and satellites in space. NASA’s Meteoroid Environment Office prepares meteoroid forecasts for missions like Artemis I, the first integrated test of NASA’s deep space exploration systems: the Orion spacecraft, Space Launch System rocket, and the ground systems at Kennedy Space Center in Cape Canaveral, Florida. The Artemis I launch is currently targeted for Aug. 29.

For more information on NASA’s All Sky Fireball Network, visit:

https://fireballs.ndc.nasa.gov 

To follow and share meteor updates, visit:

https://www.facebook.com/NasaMeteorWatch

By Hannah Maginot

Saturn to Reach Opposition Aug. 14

Saturn will have one of its best viewing opportunities of the year in the period surrounding Sunday, Aug. 14. Or it would, if the nearly Full Moon doesn’t spoil our fun.

On that date, Saturn will reach opposition – the point where it lies directly opposite the Sun in our night sky – around midnight local time for most stargazers, with the constellation Capricornus behind it.

Saturn will be visible for much of the night, rising above the southeastern horizon and lingering high in the southern sky. This will occur during Saturn’s perigee – its closest approach to Earth – making it even larger and brighter than usual.

An illustration of NASA's Cassini spacecraft in orbit around Saturn, where it documented the ringed planet in 2017.
An illustration of NASA’s Cassini spacecraft in orbit around Saturn, where it documented the ringed planet in 2017. (NASA/JPL-Caltech)

But as previously noted the last blog, the Moon will become full Aug. 11-12, and its bright wash of light will challenge spotters to clearly make out much around it in the night sky. Hopefully, Saturn’s position – west of the rising Moon – won’t cause it to be directly impacted.

The best thing about opposition this year is that Saturn will be visible all night long, said Caleb Fassett, a planetary scientist at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “That gives stargazers a good, long chance to find and observe it,” he said.

And despite the light-clutter from the Moon, all may not be lost. The rings of Saturn will face Earth at a 13-degree angle to our line of sight. And though Saturn is much farther from the Sun than our planet – an average 886 million miles out, compared to 94.4 million for Earth – a unique phenomenon may lend it even greater brightness during opposition.

The Seeliger effect, named for German astronomer Hugo von Seeliger, who died in 1924, identifies a dramatic brightening of a distant body or particle field when illuminated from directly behind the observer. With Earth passing between Saturn and the Sun, the sixth planet’s icy rings are likely to brighten perceptibly in the hours around opposition. 

Even so, it will still require a telescope to spot Saturn – which takes 29.4 Earth years to complete a single solar orbit – as anything more than a bright point of light.

Fassett recommends a 4-inch to 8-inch telescope to fully resolve the rings and provide a good look at the planet itself during opposition. With a decent telescope, it may even be possible to catch a glimpse of Titan and other Saturnian moons.

“It’s always pretty cool to see the distant planets, and Saturn is wild,” Fassett said. “Its rings and other unique characteristics make it a great subject of study for amateur astronomers and young space enthusiasts, and its moons are of great scientific interest.”

Among them is Titan, largest of Saturn’s moons, and the destination for NASA’s planned Dragonfly mission. Set to launch in 2027, Dragonfly will deliver an 8-bladed rotorcraft to the icy surface of Titan in the mid-2030s. There, it will examine the atmosphere and take samples of the surface, advancing our search for the building blocks of life and characterization of Titan’s habitability.

Learn more about Saturn here.

by Rick Smith

Perseids Meteor Shower on the Way

The Perseids are back! Well… sort of.

Usually bringing one of the most vivid annual meteor showers visible in Earth’s night sky, commonly delivering 50-100 “shooting stars” per hour at its height, the Perseids will peak Aug. 12 and 13. There’s just one problem: the full Moon.

A shower of Perseid meteors lights up the sky in 2009 in this NASA time-lapse image.
A shower of Perseid meteors lights up the sky in 2009 in this NASA time-lapse image. (NASA/JPL)

“Sadly, this year’s Perseids peak will see the worst possible circumstances for spotters,” said NASA astronomer Bill Cooke, who leads the Meteoroid Environment Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “Most of us in North America would normally see 50 or 60 meteors per hour,” he said, “but this year, during the normal peak, the full Moon will reduce that to 10-20 per hour at best.”

The Moon is so much brighter than anything else in the night sky, and it will wash out all, but the very brightest Perseids as they streak through our atmosphere and burn up far overhead.

As the full Moon subsides, the Perseids will begin to wane Aug. 21-22 and cease completely by Sept. 1. They’re the debris remnants of Comet Swift-Tuttle, a lumbering “snowball” composed of ice, rock, and dust, which orbits our Sun every 133 years. The comet itself was last visible to us in 1992 and won’t pass our way again until 2125.

How far back sightings of the Perseids actually go remains a matter of some contention, Cooke said. The comet itself wasn’t identified until 1862, but the meteor shower was seen over medieval Europe. The annual event came to be known as “the Tears of St. Lawrence,” named for the last of seven Roman church deacons martyred by the emperor Valerian in August of the year 258.

So, this is probably not the best year to make a special trip in order to see the Perseids, but, if you find yourself outside between midnight and dawn on Aug. 13, don’t forget to look up anyway.  Because you never know – you might just catch one of the bright Perseid meteors that defies the glare of the Moon. Also, the occasional early Perseid can streak across the sky as much as a week beforehand.

If you want to know what else is in the sky for August, check out the latest “What’s Up” video from Jet Propulsion Laboratory:

by Rick Smith

New meteor shower? How many meteors will I see, really?

Astronomers are excited about the possibility of a new meteor shower May 30-31. And that excitement has sparked a lot of information about the tau Herculids. Some has been accurate, and some has not.

We get excited about meteor showers, too! But sometimes events like this don’t live up to expectations – it happened with the 2019 Alpha Monocerotid shower, for example. And some astronomers predict a dazzling display of tau Herculids could be “hit or miss.”

This infrared image from NASA's Spitzer Space Telescope shows the broken Comet 73P/Schwassman-Wachmann 3.
This infrared image from NASA’s Spitzer Space Telescope shows the broken Comet 73P/Schwassman-Wachmann 3 skimming along a trail of debris left during its multiple trips around the sun. The flame-like objects are the comet’s fragments and their tails, while the dusty comet trail is the line bridging the fragments. (Credit: NASA)

So, we’re encouraging eager skywatchers to channel their inner scientists, and look beyond the headlines. Here are the facts:

  • On the night of May 30 into the early morning of May 31, Earth will pass through the debris trails of a broken comet called 73P/Schwassmann-Wachmann, or SW3.
  • The comet, which broke into large fragments back in 1995, won’t reach this point in its orbit until August.
  • If the fragments from were ejected with speeds greater than twice the normal speeds—fast enough to reach Earth—we might get a meteor shower.
  • Spitzer observations published in 2009 indicate that at least some fragments are moving fast enough. This is one reason why astronomers are excited.
  • If a meteor shower does occur, the tau Herculids move slowly by meteor standards – they will be faint.

Observers in North America under clear, dark skies have the best chance of seeing a tau Herculid shower. The peak time to watch is around 1am on the East Coast or 10pm on the West Coast.

We can’t be certain what we’ll see. We can only hope it’s spectacular.

Mars-Jupiter Conjunction Visible May 29

Most stargazers will have a prime viewing opportunity to see the planets Mars and Jupiter draw incredibly close in the predawn sky on the nights of May 27-30.

Sky chart showing how Jupiter and Mars will appear in the pre-sunrise sky on May 28-30.
Sky chart showing how Jupiter and Mars will appear in the pre-sunrise sky on May 28-30. Credits: NASA/JPL-Caltech

The two planets will appear 20 degrees or so above the horizon in the eastern-southeastern sky, against the constellation Pisces, approximately 45 minutes before local sunrise. This Mars-Jupiter conjunction will be visible, barring local weather issues, in the predawn hours each morning from May 27 to May 30. The conjunction will peak at 3:57 a.m. CDT on May 29.

“Planetary conjunctions traditionally have been more the stuff of astrology than serious astronomy, but they never fail to impress during observations, particular when the gas giants are involved,” said Mitzi Adams, an astronomer and researcher at NASA’s Marshall Space Flight Center in Huntsville, Alabama.

During such a conjunction, two planets appear close together in Earth’s night sky. In the case of Earth’s solar system, conjunctions happen frequently because our sister planets travel around the Sun in a fairly similar ecliptic plane, often appearing to meet in our night sky despite being millions of miles away from one another.

At their closest point, Mars and Jupiter will be separated by no more than 0.6 degrees. Astronomers routinely use degrees to measure the angular distance between objects in the night sky. To observers on the ground, the distance between the two planets will be no more than the width of a raised finger, with Mars appearing just to the lower right of the massive gas giant.

It might be necessary to use binoculars or a telescope to spot Mars clearly, said Alphonse Sterling, a NASA astronomer who works with Adams at Marshall. But he noted that observers should have no trouble identifying Jupiter, even with unaided eyes.

“We anticipate Jupiter will shine at a magnitude of -2.2,” Sterling said. “Mars, in comparison, will have a magnitude of just 0.7.”

The brightness of celestial bodies is measured according to their magnitude value, a number which decreases as brightness increases. A negative value indicates the planet or moon is easy to see in the night sky, even with ambient light from one’s surroundings.

Mars and Jupiter are millions of miles away from us, of course – more than 136 million miles will separate Earth and Mars at the time of the conjunction, with Jupiter nearly four times further away. Even so, Jupiter will be the far brighter of the two. With its planetary diameter of around 4,200 miles, Mars is dwarfed by the massive Jovian giant, which has a diameter of about 89,000 miles. Being so much smaller, Mars reflects far less sunlight.

Mars also orbits the Sun more quickly, spinning eastward in our night sky fast enough to leave its lumbering gas-giant counterpart behind. Mars will catch up to Jupiter again and pass it during another conjunction in August 2024.

Adams and Sterling look forward to spotting the planetary conjunction.

“It’s thrilling to look up and recognize that these two worlds represent the breadth of NASA’s planned and potential goals for science and exploration,” Adams said. “As NASA prepares to send the first human explorers to the planet Mars, the possibilities could be virtually limitless for groundbreaking science discoveries among Jupiter’s fascinating moons.”

“This conjunction brings together two vastly different worlds, which both hold incredible promise to help us better understand our solar system, humanity’s place in the cosmos, and where we may be headed as a species,” Sterling added.

“Get outside before sunrise on May 29 and see them for yourself – and imagine all we’ve yet to learn from them,” he added.

Enjoy this celestial event as you watch the skies!

By Rick Smith

Total Lunar Eclipse on View May 15-16

On the night of May 15, and into the early hours of May 16, skywatchers will be treated to a phenomenon which takes place every 1.5 years or so: a total lunar eclipse.

Total lunar eclipses occur when the Moon and Sun are on opposite sides of Earth and the planet casts a complete shadow, or umbra, over its sole natural satellite. There may be multiple partial lunar eclipses each year, but total eclipses are a bit rarer. Best of all, unlike the precautions one takes to observe a total solar eclipse, it’s completely safe to watch a lunar eclipse unfold with the unaided eye. Even so, binoculars or a powerful telescope definitely can enrich the experience.

A nearly total eclipse
A nearly total eclipse of November’s full “Beaver Moon” captured over the city of New Orleans before dawn on Nov. 19, 2021. The 97% eclipse clocked in at 3 hours, 28 minutes, and 24 seconds, making it the longest partial lunar eclipse in 580 years. Credits: NASA/Michoud Assembly Facility

The partial eclipse phase will begin over North America at 9:28 p.m. Central Daylight Time on May 15. Totality will begin at 10:29 p.m. CDT, concluding about midnight. After totality, the partial phase will end at 12:56 a.m. CDT on May 16.

This full Moon was known by early Native American tribes as the Flower Moon because this was the time of year when spring flowers appeared in abundance.

Mitzi Adams and Alphonse Sterling, both astronomers at NASA’s Marshall Space Flight Center in Huntsville, Alabama, are particularly excited to observe the lunar eclipse. One of the most recent such events they documented – in January 2018 – was very low on the horizon, with trees and buildings partially obscuring the eclipse during totality.

Then, of course, the global COVID-19 pandemic put a damper on eclipse watch parties in 2020-2021.

A telescopic visualization of the total lunar eclipse
A telescopic visualization of the total lunar eclipse, happening May 15-16, 2022.
Credits: NASA/Goddard/Ernie Wright

“It’s exciting to get back to holding astronomical society events in person, where it’s safer to share a telescope eyepiece,” Adams said.

Unlike a total solar eclipse – in which ideal viewing is limited to a roughly 100-mile-wide “path of totality” as the shadow of Earth’s Moon sweeps across the land relative to the position of the Sun – a lunar eclipse has no such limits.

“The whole half of Earth in darkness during those hours will be able to see it,” Sterling said. “You don’t have to work too hard to find a good vantage point. Just go outside!”

What can viewers expect to see? As Earth’s shadow deepens on the face of the Moon, it will darken to a ruddy, red color, with its intensity depending on atmospheric interference.

It’s no surprise observers coined the ominous-sounding phrase “blood moon,” but the effect is completely natural. During the eclipse, most visible-spectrum light from the Sun is filtered out. Only the red and orange wavelengths reach the surface.

The blocking of the Moon’s reflected light has another benefit, Adams said.

“No moon means more visible stars,” she said. “During totality, if the skies are clear, we may even be able to see the Milky Way itself, showing up as a hazy white river of stars stretching away in a curving arc.”

Sterling notes that the long duration of the total eclipse offers amateur shutterbugs plenty of time to experiment with photographing the event. He recommends trying varying exposure times with conventional cameras for maximum effect.

He and Adams both emphasize the value of putting the camera aside, as well.

“Just watch it happen,” Adams said. “Looking at the Moon, it’s hard not to think about the people who actually walked there, and about those who soon will do so again – when NASA’s Artemis program launches the next human explorers to the Moon in coming years.”

Sterling said the most valuable aspect of the event is the chance to spark wonder in young minds. “We don’t get a lot of groundbreaking astronomical information from lunar eclipses, but they’re a great way to inspire discussion and engage the astronomers and explorers of tomorrow,” he said.

Find out how to watch the total lunar eclipse with NASA Science Live on Facebook. Learn more about NASA’s observations of eclipses, and inspire young stargazers with activities and information.

You can also learn more about lunar eclipses via the video below:

Happy skywatching!

by Rick Smith

Meteor Showers to Bookend Overnight Skywatching Opportunities in May

As the spring season continues, May could prove to be of great interest for stargazers and space enthusiasts – with a pair of potentially active meteor showers opening and closing the month.

“Meteors aren’t uncommon,” Bill Cooke said, who leads NASA’s Meteoroid Environment Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “Earth is bombarded every day by millions of bits of interplanetary detritus speeding through our solar system.”

A meteor mosaic comprised of 99 images, using a blue filter, of the Eta Aquariids observed during the early morning hours
A meteor mosaic comprised of 99 images, using a blue filter, of the Eta Aquariids observed during the early morning hours from April 30 to May 8, 2013.
Credits: NASA All Sky Fireball Network

Most particles are no bigger than dust and sand. Hitting the upper atmosphere at speeds up to 45 miles per second, they flare and burn up. On any given night, the average person can see from 4 to 8 meteors per hour. Meteor showers, however, are caused by streams of comet and asteroid debris, which create many more flashes and streaks of light as Earth passes through the debris field.

“It’s a perfect opportunity for space enthusiasts to get out and experience one of nature’s most vivid light shows,” Cooke said.

Eta Aquariids (May 5-6)

First up, on the night of May 5 and early hours of May 6, around 3:00 am CDT, is the eta Aquariid shower, caused by the annual encounter with debris from Halley’s comet – remnants of the comet’s tour through the solar system once every 75 or 76 years. Its radiant – or the point in the night sky from which the meteor shower appears to originate – is the constellation Aquarius. The shower is named for the brightest star in that constellation, eta Aquarii.

A 2013 eta Aquariid composite
A 2013 eta Aquariid composite from a camera used in New Mexico.
Credits: NASA Meteoroid Environment Office

Until Halley’s comet is next visible from Earth in 2061, only the eta Aquariids – and their fall counterpart, the Orionid meteor shower, which is visible each October – mark the passage of this solar system visitor.

“It will be interesting to see if the rates are low this year, or if we will get a spike in numbers before next year’s forecast outburst,” Cooke said.

The annual meteor shower has the best rates for those in the Southern Hemisphere, but even in the Northern Hemisphere, if weather conditions are right, there is a possibility of seeing up to 30 meteors per hour. The waxing crescent Moon will set before the eta Aquariid radiant gets high in the sky, leaving dark skies for what should be an excellent show. Best viewing happens after 3 AM local time, so get up early.

Tau Herculids (May 30-31)

A possible newcomer this year is the tau Herculid shower, forecast to peak on the night of May 30 and early morning of May 31.

Back in 1930, German observers Arnold Schwassmann and Arno Arthur Wachmann discovered a comet known as 73P/Schwassmann-Wachmann, or “SW3, which orbited the Sun every 5.4 years. Being so faint, SW3 wasn’t seen again until the late 1970s, seeming pretty normal until 1995, when astronomers realized the comet had become about 600 times brighter and went from a faint smudge to being visible with the naked eye during its passage. Upon further investigation, astronomers realized SW3 had shattered into several pieces, littering its own orbital trail with debris. By the time it passed our way again in 2006, it was in nearly 70 pieces, and has continued to fragment further since then.

If it makes it to us this year, the debris from SW3 will strike Earth’s atmosphere very slowly, traveling at just 10 miles per second – which means much fainter meteors than those belonging to the eta Aquariids. But North American stargazers are taking particular note this year because the tau Herculid radiant will be high in the night sky at the forecast peak time. Even better, the Moon is new, so there will be no moonlight to wash out the faint meteors.

“This is going to be an all or nothing event. If the debris from SW3 was traveling more than 220 miles per hour when it separated from the comet, we might see a nice meteor shower. If the debris had slower ejection speeds, then nothing will make it to Earth and there will be no meteors from this comet,” Cooke said.

Learn more about meteors and meteorites. Also, if you want to know what else is in the sky for May, check out the latest “What’s Up” video from Jet Propulsion Laboratory:

Enjoy all this month has to offer as you watch the skies!

by Rick Smith

Loud fireball spotted over southern Mississippi mostly heard, hardly seen

A fiery meteor streaked across the morning skies in southern Mississippi yesterday on April 27, 2022.

More than 30 eyewitnesses in the states of Arkansas, Louisiana and Mississippi reported seeing a bright fireball at 8:03 a.m. CDT. The sighting was soon followed by numerous reports of loud booms heard in Claiborne County, Mississippi, and surrounding counties.

GLM image from the GOES 16 satellite.
GLM image from the GOES 16 satellite. Credits: NOAA

Approximately 22,000 miles out in space, NOAA’s Geostationary Lightning Mappers (GLM) onboard the Geostationary Operational Environmental Satellites (GOES) 16 and 17 detected several bright flashes associated with the fragmentation’s of this bolide, or exceptionally bright meteor, which was first spotted 54 miles above the Mississippi River near the Mississippi town of Alcorn.

“This is one of the nicer events I have seen in the GLM data,” said Bill Cooke, lead of NASA’s Meteoroid Environments Office at Marshall Space Flight Center in Huntsville, Alabama.

Fireball ground track from eyewitness accounts.
Fireball ground track from eyewitness accounts. Credits: NASA/American Meteor Society

The object – thought to be a piece of an asteroid about a foot in diameter with a weight of 90 pounds – moved southwest at a speed of 55,000 miles per hour, breaking into pieces as it descended deeper into Earth’s atmosphere. It disintegrated about 34 miles above the swampy area north of Minorca in Louisiana.

The fragmentation of this fireball generated an energy equivalent of 3 tons of TNT (trinitrotoluene), which created shock waves that propagated to the ground, producing the booms and vibrations felt by people in the area.

At its peak, the fireball was over 10 times brighter than the Full Moon.

“What struck me as unusual was how few eyewitness reports we had given the skies were so clear,” said Cooke. “More people heard it than saw it.”

by Lance D. Davis