Are you ready for November’s sky watching highlights? Cool autumn evenings are a great time to look for the Pleiades star cluster. You’ll also have a couple of great opportunities to observe the Moon with Jupiter and Saturn. Plus, check out the phenomenon known as Earthshine. Learn about all that and more from NASA’s Jet Propulsion Laboratory’s video below!
Author: Marshall Space Flight Center
‘Once in a Blue Moon’ Coming Soon
by Lauren Lambert
There’s an extra special treat coming Earth’s way – a Blue Moon on the night of Oct. 31 for Halloween.
What is a Blue Moon?
According to modern folklore, it is a phenomenon where a Full Moon appears twice in one calendar month. Typically, each month has only one, as Full Moons occur about 29 days apart.
Our first Full Moon of the month – known as a Harvest Moon – occurred on Oct. 1. This is a name given to the Full Moon happening closest to the autumnal equinox – the first day of fall. The Blue Moon coming up is respectively known as the Hunter’s Moon. Rising in the early evening, the Hunter’s Moon was given its name because it provided plenty of moonlight for hunters to gather meat for the long winter ahead.
While the informal phrase “once in a Blue Moon” refers to something that rarely happens, the same definition rings true for the skies this Halloween. These moons are of significance because they only come every two or three years. In fact, the last Blue Moon occurred on March 31, 2018.
Contrary to its name, a Blue Moon has nothing to do with the Moon having a blue hue. However, very rarely there are actual blue-tinted Moons due to particles thrown into the atmosphere by natural catastrophes. In 1883, an Indonesian volcano called Krakatoa had an eruption so large that it was compared by scientists to a 100-megaton nuclear bomb. Lots of ash from the Krakatoa explosion rose into the atmosphere. Many of these ash particles were about 1 micron in size, which could scatter red light and act as a blue filter. This resulted in the Moon appearing blue.
Blue-colored Moons appeared for years following the 1883 eruption. Many other volcanos and even wildfires throughout history have been known to affect the color of the moon. As a rule of thumb, in order to create a bluish Moon, dust or ash particles must be larger than ~0.6 microns, which is the wavelength of red light. Having said that, what we call a Blue Moon appears pale grey and white – just like the Moon on any other night. Having a second Full Moon in one given month does not change its color.
October’s Blue Moon, however, will be the first Blue Moon to appear on Halloween since 1944. This moon occurred one month following the introduction of the Aggregat 4, or the V-2 rocket. This rocket was the first vehicle capable of reaching the edge of space. In years following, the Apollo Saturn V became its direct descendant.
As we approach October 2020’s Blue Moon, the Artemis Generation prepares to explore the Moon’s surface from a lunar base. NASA’s Artemis program is named after the twin sister to Apollo, the Sun god in Greek mythology, and she is known as the goddess of the Moon. There hasn’t been this much momentum to return to the Moon’s surface since the Apollo missions.
The next Halloween Blue Moon will occur in 2039. By then, the Artemis Generation will hopefully look at Mars from that same lunar base – perhaps passing the torch to an Ares Generation bound for the Red Planet.
It’s All About Mars in October
by Lance D. Davis
NASA is developing a path for an exciting journey to Mars – a rich destination for scientific discovery and human exploration as we expand our presence into the solar system. This month of October brings an amazing night-sky view of the Red Planet.
Mars is currently visible, reaching its highest point in the sky around midnight. Earth’s closest neighbor is also at its brightest and will remain that way well into November.
Right now, Mars is the third brightest object in Earth’s night. The Moon and Venus are the two brightest objects, and usually Jupiter is third. But for this season, Mars is passing close enough to Earth to outshine Jupiter. This great visibility of Mars coincides with an event known as opposition, which happens every two years and two months.
Opposition occurs when the orbit of a planet, such as Mars, takes it near the Earth. Just like runners passing each other on a track, the faster, inner planets, such as Earth, can approach and overtake slower-moving outer planets like Mars. When the planets pass each other during this opposition, Mars’ proximity means it will appear larger and brighter in our sky. Because the Sun, Earth, and Mars are lined up during this passing, Mars will rise at sunset, having a high overhead at midnight. This is the closest the Red Planet will come to Earth for the next 15 years, or until September 2035.
At its furthest, Mars reaches about 250 million miles (400 million km) from Earth. During the October opposition, it will be as close as 40 million miles (60 million km) – nearly seven times closer. Although Mars will still look like a bright star to the unaided eye, it will grow dramatically in size when seen in a telescope. This year, Mars’ closest approach to Earth happens just a week before the opposition on Oct. 13, giving the Red Planet its biggest, apparent size of the 2020’s.
When it comes to observing Mars around opposition, telescopes will show more of the planet’s details, such as dark and light regions on Mars’ surface, and the prominent south polar ice cap, which will be tilted towards the Earth. Due to the turbulence of our atmosphere, these details can be hard to see, especially in smaller telescopes.
Many amateur astronomers use a color video camera attached to their telescope, running special software that selects the best frames to stack into a single image. This helps in negating the blurring caused by the air.
The most striking thing about Mars’ appearance – whether seen with the naked eye or through a telescope – is its red color. This color is caused by iron in the rocks on Mars’ surface – the same thing that causes the red color in sandstone formations in the southwestern US.
So, when you spot Mars, keep your eye on it and enjoy its fiery, red brightness!
Sky Watching Highlights for October 2020
There’s plenty to see in the sky for October! The Moon will be full not once, but twice this month. It’s also a great time for viewing Mars and trying to spot the galaxy of Andromeda. Learn more from the video below produced by NASA’s Jet Propulsion Laboratory.
International Observe the Moon Night 2020
by Lance D. Davis
International Observe the Moon Night is a worldwide public event encouraging observation, appreciation and understanding of our Moon and its connection to NASA exploration and discovery.
This is a great time to celebrate the Moon with enthusiasts and curious people all over Earth as excitement grows about NASA’s Artemis program, which will send the next man and first woman to the Moon.
Since 2010, the celebration has occurred annually in September or October when the Moon is around first quarter – a great phase for excellent viewing opportunities.
You can join NASA’s Marshall Space Flight Center for a live planetarium show Saturday, Sept. 26 at 6:30 p.m. CDT – available online to everyone via YouTube and Facebook. Interviews with planetary and citizen scientists will also be included.
This virtual event is brought to you by the Planetary Missions Program Office at Marshall and U.S. Space & Rocket Center.
Whether it’s outdoors, at home, online, or wherever you may be, you are encouraged to be a part of International Observe the Moon Night. Please remember to follow your local health and safety guidelines.
Learn more and find other events here.
The Autumnal Equinox is Near
Happy equinox, Earthlings! Sept. 22 marks the fall equinox, when day and night are nearly equal.
“However, that day/night length depends on where you are on Earth,” said NASA solar scientist Mitzi Adams. “For example, at the North and South Poles, the length of the day and night is six months!”
At the North Pole, the Sun will sink below the horizon for a kind of twilight from now until sometime in October when it will be completely dark, explained Adams. Spring twilight begins a few weeks before the vernal, or spring, equinox in March, when the Sun rises above the horizon again.
This only happens twice in Earth’s year-long trip around the Sun. The rest of the year, the Sun shines unevenly over the Northern and Southern Hemispheres. That’s because Earth’s axis is tilted with respect to the Sun-Earth plane. But on these special days – the spring and fall equinox – the Sun shines equally on both north and south.
Here in the Northern Hemisphere, it’s the first day of astronomical fall. From now until the beginning of spring, nighttime hours will last longer than daylight as the Sun travels a shorter arc across the sky each day. The Sun has its shortest path of the year at the time of the winter solstice — the shortest day and longest night of the year — when sunrise and sunset are as far south as they can go (at any one location). It’s just the opposite in the Southern Hemisphere, where September 22 kicks off astronomical spring.
The equinox—meaning “equal night” in Latin—occurs at 8:31 a.m. CDT.
Sky Watching Highlights for September 2020
This month spot the Moon together with Mars and Venus, along with the flickering star Fomalhaut, which had itself a planet…until it didn’t! Check out the video below produced by NASA’s Jet Propulsion Laboratory to learn more.
Perseids Peak: Watch Best Meteor Shower of the Year!
By Emily Clay
The Perseid meteor shower is here! With Comet NEOWISE making its way out of the solar system, it is time for a celestial show caused by a different comet. Perseid meteors, caused by debris left behind by the Comet Swift-Tuttle, began streaking across the skies in late July and will peak in the pre-dawn hours of Aug. 12.
The Perseid meteor shower is often considered to be one of the best meteor showers of the year due to its high rates and pleasant late-summer temperatures. This year’s shower, however, has the unfortunate circumstance of the Moon phase—last quarter—impeding the view of the shower peak, reducing the visible meteors from over 60 per hour down to 15-20 per hour. But the Perseids are rich in bright meteors and fireballs, so it will still be worth going out in the early morning to catch some of nature’s fireworks.
WHEN SHOULD I LOOK?
Make plans to stay up late the night of Aug. 11 or wake up early the morning of Aug. 12. The Perseids are best seen between about 2 a.m. your local time and dawn. The Moon rises at around midnight, so its brightness will affect the peak viewing window. However, even though the Moon’s phase and presence will keep the frequency of visible meteors lower, there is still nearly one meteor every two minutes during the peak!
If those hours seem daunting, not to worry! You can go out after dark, around 9 p.m. local time, and see a few Perseids. Just know that you won’t see nearly as many as you would had you gone out during the early morning hours.
How can you see the Perseids if the weather doesn’t cooperate where you are? A live broadcast of the meteor shower from a camera at NASA’s Marshall Space Flight Center in Huntsville, Alabama, (if our weather cooperates!) will be available on the NASA Meteor Watch Facebook starting around 8 p.m. CDT on Aug. 11 and continuing until sunrise on Aug. 12. Meteor videos recorded by the NASA All Sky Fireball Network are also available each morning; to identify Perseids in these videos, look for events labeled “PER.”
WHY ARE THEY CALLED PERSEIDS?
All meteors associated with one particular shower have similar orbits, and they all appear to come from the same place in the sky, called the radiant. Meteor showers take their name from the location of the radiant. The Perseid radiant is in the constellation Perseus. Similarly, the Geminid meteor shower, observed each December, is named for a radiant in the constellation Gemini.
HOW TO OBSERVE PERSEIDS
If it’s not cloudy, pick an observing spot away from bright lights, lay on your back, and look up! You don’t need any special equipment to view the Perseids – just your eyes. (Note that telescopes or binoculars are not recommended because of their small fields of view.) Meteors can generally be seen all over the sky so don’t worry about looking in any particular direction.
While observing this month, not all of the meteors you’ll see belong to the Perseid meteor shower. Some are sporadic background meteors. And some are from other weaker showers also active right now, including the Alpha Capricornids, the Southern Delta Aquariids, and the Kappa Cygnids. How can you tell if you’ve seen a Perseid? If you see a meteor try to trace it backwards. If you end up in the constellation Perseus, there’s a good chance you’ve seen a Perseid. If finding constellations isn’t your forte, then note that Perseids are some of the fastest meteors you’ll see!
Pro tip: Remember to let your eyes become adjusted to the dark (it takes about 30 minutes) – you’ll see more meteors that way. Try to stay off of your phone too, as looking at devices with bright screens will negatively affect your night vision and hence reduce the number of meteors you see!
Sky Watching Highlights for August 2020
The month of August brings a bunch of opportunities to see the Moon posing with the planets. Plus, here come the meteors! Learn more via the video below produced by NASA’s Jet Propulsion Laboratory.
See Comet NEOWISE! A Once-in-a-Lifetime Event
For Comet Vocabulary, please read to the end of the post.
For most, early July is when most people living in the United States look to the skies to watch dazzling firework shows. However, this month there is a different kind of show happening in the sky.
Comet Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) was only discovered a few months ago on March 27 by NASA’s NEOWISE telescope and has quickly become a popular solar system visitor. Its popularity is warranted, however, as it is the brightest comet since Comet Hale-Bopp that passed by Earth 23 years ago in 1997.
Comet nuclei are cosmic snowballs of frozen gases, rock and dust that orbit the sun. They can range in size from a few miles to tens of miles wide, and the nucleus of NEOWISE measures about 3 miles across. When these comets approach the sun, their frozen bodies start to sublimate, and they spew dust and gasses in a tail that can span millions of miles.
Comet NEOWISE made its harrowing close approach to the sun, known as its perihelion, on July 3, and it is now zooming past the Earth on its way back out of the solar system. NEOWISE will make its closest approach (64 million miles) to Earth on July 22, but the best viewing window is happening right now until July 19.
NEOWISE can be seen with the naked eye, but for an even better viewing experience, binoculars or even a telescope is recommended. As for which to choose, binoculars are your current best option. “Definitely use binoculars for now – the tail of NEOWISE is at least 7 degrees long, which is much bigger than the field of view of most telescopes,” said Bill Cooke, lead of NASA’s Meteoroid Environment Office at Marshall Space Flight Center. “Binoculars will allow you to see the whole thing, whereas a telescope only shows a tiny part.”
To see NEOWISE, start looking in the northwestern sky about an hour after sunset. The comet will be below the stars that make up the bowl of the Big Dipper and shining nearly as brightly at a magnitude 3. If you are an early riser, you can still see NEOWISE about an hour before sunrise in the northeastern horizon until the end of the week.
You need a clear view of the horizon to see this comet. Beaches, fields, and areas with higher elevations are all great observation spots. In areas with more light pollution, binoculars may be necessary for viewing. This is definitely a once-in-a-lifetime event, as NEOWISE won’t be visiting again for 6,800 years!
Learn more about comets at NASA’s Solar System Exploration website.
For comet-related, kid-friendly activities, visit NASA Science Space Place.
Comet – Made up of ice, dust and gas which form a coma and sometimes a visible tail when it is orbiting close to the sun
Nucleus – The head of the comet, which is made up of ice and frozen gas that vaporizes to form the coma and the tail
Sublimate – The transition of a substance directly from the solid to the gas state, without passing through the liquid state
Perihelion – The point where an object orbiting the sun is closest to the sun
Magnitude – The units used to describe brightness of astronomical objects. The smaller the numerical value, the brighter the object is