Kuiper Kat's Astronomy @kuiperkat - Tumblr Blog

fucks me up that by total coincidence the sun and moon's size difference is exactly matched to their difference in distance from us, thus making our beautiful total solar eclipses where you can see the silver threads of the sun's corona possible because the moon just covers the sun completely

The stars (literally) aligned just right for this experience to be possible. It's likely that aliens don't have this

uncivilliberties

The moon is also absolutely gargantuan by moon standards. It isn't the largest moon in the solar system, but it is BY FAR the largest in comparison with its planet. Ganymede is the largest satellite of Jupiter and the largest moon in the solar system. Its diameter is only about 3.8% of Jupiter's. Titan's radius is 4.4% of Saturn's. Callisto and Io are the next largest in the neighborhood, with 3.4% and 2.6% the diameter of Jupiter respectively.

Our moon is number 5. It is smaller in direct comparison to the above moons. The diameter of the moon is 3475 km. That is a full 27% of the diameter of the Earth. More than a quarter. That's ridiculous. It's unheard of. The universe is large enough that the word unique probably doesn't mean a lot, but this might be about as close as you get.

This has had a huge impact on our planet. Other things aliens might not have are significant tides. One of Mars's dumpy little potatoes wouldn't be able to move oceans the way our moon does.

Our moon has also stabilized our axis to a massive degree. Without her up there our axis would wobble all over the place and our climate would be far more chaotic. Aliens might not be quite so lucky.

I guess what I am really trying to say is that the moon is extremely cool. I like the moon.

willowdove

Just want to add that the reason we have such a large moon is because a whole planet crashed into proto-Earth. Theia (the planet) and Earth got so superheated by this collision that their component cores fused and the impact jettisoned a lot of material into space. That massive amount of jettisoned material became our moon. So Earth and the moon have very similar composition. This does not seem to be a common method of lunar formation.

gandalfsbignaturals

what if the answer to the fermi paradox is that life cant exist without a moon like luna

habbadax

I got a serious beef with the Fermi paradox. There is no Fermi paradox. There stopped being a Fermi paradox once the first radio telescopes went up, and we began to get a true sense of the sheer scale of the universe.

Space is big, empty, and loud. Sunspots can cause enough interference to affect global communications. We’re not even loud enough to talk over our own sun. On our own planet. We can barely communicate with Voyager, and we know exactly where it is and what its signal sounds like.

The Fermi paradox is like doubting the existence of Belfast, because you stood on a windy New York beach shouting towards it and didn’t get an answer.

headspace-hotel

kactusnz

i didn't realise we were drowned out by our own sun :(

derinthescarletpescatarian

She is screaming so loud

roversrovers

does it ever drive you crazy

just how fast the night changes

rawyld

Me too and yet the rest of the world just doesn’t seem to care about going to the Moon anymore. It is so sad that people don’t seem to be so excited as they use to be in the 1960’s.

droideplane

I understand why some people don't really care (we've done it before, lots of stressors in daily life, political opinions, etc). However, space exploration and moon missions are such joyful events. I think they're a good way to step back from the craziness and take a look at the bigger picture of our place in the universe and how we can explore it peacefully.

unpluggedlamp1

let’s forget about politics and do moon stuff instead. that seems fun. i like moon.

After the American Astronomical Society meeting in January, Sky-Watcher Telescopes sent me this incredible gift: the Heliostar 76mm Hydrogen Alpha Solar Telescope!

I was able to attach my iPhone to the Heliostar today and get some incredible views of our closest star.

I can't thank the Sky-Watcher team enough; this will be an incredible scope to use for outreach in NYC!

#amateur astronomy #sungazing #solar astronomy #sidewalk astronomy #astronomy #hydrogen alpha #Hα #women in stem #latinas in stem

🎶It's tiiiiiiime🎶

Are you passionate about sharing science communication on your social media platforms? Apply for the Artemis II NASA Social and take part in the upcoming launch of the first crew to orbit the Moon since 1972! Visit the link to learn more 🌎🚀🌓

Lee esta nota en español aquí

#nasa #artemis #moon #NASA social #artemis 2

October’s Night Sky Notes: Let’s Go, LIGO!

by Kat Troche of the Astronomical Society of the Pacific

September 2025 marks ten years since the first direct detection of gravitational waves as predicted by Albert Einstein’s 1916 theory of General Relativity. These invisible ripples in space were first directly detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO). Traveling at the speed of light (~186,000 miles per second), these waves stretch and squeeze the fabric of space itself, changing the distance between objects as they pass.

Waves In Space

Gravitational waves are created when massive objects accelerate in space, especially in violent events. LIGO detected the first gravitational waves when two black holes, orbiting one another, finally merged, creating ripples in space-time. But these waves are not exclusive to black holes. If a star were to go supernova, it could produce the same effect. Neutron stars can also create these waves for various reasons. While these waves are invisible to the human eye, this animation from NASA’s Science Visualization Studio shows the merger of two black holes and the waves they create in the process.

Two black holes orbit each other, generating space-time ripples called gravitational waves in this animation. As the black holes get closer, the waves increase in until they merge completely. NASA's Goddard Space Flight Center Conceptual Image Lab

How It Works

A gravitational wave observatory, like LIGO, is built with two tunnels, each approximately 2.5 miles long, arranged in an "L" shape. At the end of each tunnel, a highly polished 40 kg mirror (about 16 inches across) is mounted; this will reflect the laser beam that is sent from the observatory. A laser beam is sent from the observatory room and split into two, with equal parts traveling down each tunnel, bouncing off the mirrors at the end. When the beams return, they are recombined. If the arm lengths are perfectly equal, the light waves cancel out in just the right way, producing darkness at the detector. But if a gravitational wave passes, it slightly stretches one arm while squeezing the other, so the returning beams no longer cancel perfectly, creating a flicker of light that reveals the wave’s presence.

When a gravitational wave passes by Earth, it squeezes and stretches space. LIGO can detect this squeezing and stretching. Each LIGO observatory has two “arms” that are each more than 2 miles (4 kilometers) long. A passing gravitational wave causes the length of the arms to change slightly. The observatory uses lasers, mirrors, and extremely sensitive instruments to detect these tiny changes. NASA

The actual detection happens at the point of recombination, when even a minuscule stretching of one arm and squeezing of the other changes how long it takes the laser beams to return. This difference produces a measurable shift in the interference pattern. To be certain that the signal is real and not local noise, both LIGO observatories — one in Washington State (LIGO Hanford) and the other in Louisiana (LIGO Livingston) — must record the same pattern within milliseconds. When they do, it’s confirmation of a gravitational wave rippling through Earth. We don’t feel these waves as they pass through our planet, but we now have a method of detecting them!

Get Involved

With the help of two additional gravitational-wave observatories, VIRGO and KAGRA, there have been 300 black hole mergers detected in the past decade; some of which are confirmed, while others await further study. While the average person may not have a laser interferometer lying around in the backyard, you can help with two projects geared toward detecting gravitational waves and the black holes that contribute to them:

Black Hole Hunters: Using data from the TESS satellite, you would study graphs of how the brightness of stars changes over time, looking for an effect called gravitational microlensing. This lensing effect can indicate that a massive object has passed in front of a star, such as a black hole.

Gravity Spy: You can help LIGO scientists with their gravitational wave research by looking for glitches that may mimic gravitational waves. By sorting out the mimics, we can train algorithms on how to detect the real thing.

You can also use gelatin, magnetic marbles, and a small mirror for a more hands-on demonstration on how gravitational waves move through space-time with JPL’s Dropping In With Gravitational Waves activity!

#night sky notes #kuiper kat writes #black holes #ligo

nasa

The Mascots in the Running to Fly around the Moon!

Earlier this year, the Moon Mascot design contest challenged people of all ages from all over the world to contribute ideas for the zero gravity indicator for the Artemis II mission. This plush item serves a very important purpose — it indicates when the astronauts have reached space by floating around the spacecraft! The zero gravity indicator also reminds the astronauts of Earth when they are far from home.

The Moon Mascot design contest received thousands of entries from over 50 countries — but only 25 are entering the finalist round.

“Rise” | Lucas Ye from Mountain View, California

“Rise” has a soft round body that resembles the Moon and wears a baseball cap that represents Earth. This design is inspired by the “Earthrise” photo captured in 1968 by the Apollo 8 crew.

kuiperkat

Okay, but Crust-acean is A PERFECT SPECIMEN THAT CAN DO NO WRONG

JUST LOOK AT IT

#nasa #artemis #moon #plushie #crab #gravity indicator

NASA (and Kat) Award Wins!

Back in April, NASA picked up a win at the 29th Annual Webby Awards for Video & Film Events & Live 2025, and in June, received the Emmy for Outstanding Live News Special at the 46th Annual News & Documentary Emmy Awards for their broadcast, 2024 Total Solar Eclipse: Through the Eyes of NASA.

Y'know - this broadcast:

April 2024 (look at this dweeb)

As a result of my work on this broadcast...

July 2025 (dweeb with accessories)

I WON A FLIPPIN' WEBBY AND EMMY!

I'm still trying to wrap my head around this. The biggest thanks in the world goes to the @nasa team for bringing me in on this amazing project — something I'd've never thought was possible. Huge shout out to my colleagues at @astrosocietydotorg for getting me this opportunity, to my family/friends for thinking what I do is cool, and my astrono-babe, Michael, for backing me up every step of the way 💖

#kuiper kat writes #women in stem #webby awards #emmy awards #nasa #2024 Total Solar Eclipse: Through the Eyes of NASA #achievements #amateur astronomy

July’s Night Sky Notes: Spy the Scorpion

by Kat Troche of the Astronomical Society of the Pacific

As summer deepens in the Northern Hemisphere, a familiar constellation rises with the galactic core of the Milky Way each evening: Scorpius the Scorpion. One of the twelve zodiacal constellations, Scorpius contains many notable objects, making it an observer's delight during the warmer months. Here are some items to spy in July:

This star map of the Scorpius constellation highlights the star Antares and several notable deep-sky objects like the Rho Ophiuchi Complex, Messier 4, the Cat’s Paw Nebula, and Caldwell 76, the Baby Scorpion Cluster. Credit: Stellarium Web

Antares: referred to as “the heart of the scorpion,” this supergiant has a distinct reddish hue and is visible to the naked eye. If you have good skies, try to split this binary star with a medium-sized telescope. Antares is a double star with a white main-sequence companion that comes in at a 5.4 magnitude.

Messier 4: one of the easiest globular clusters to find, M4 is the closest of these star clusters to Earth at 5,500 light years. With a magnitude of about 5.6, you can spot this with a small or medium-sized telescope in average skies. Darker skies will reveal the bright core. Use Antares as a guide star for this short trip across the sky.

Caldwell 76: If you prefer open star clusters, locate C76, also known as the Baby Scorpion Cluster, right where the ‘stinger’ of Scorpius starts to curve. At a magnitude of 2.6, it is slightly brighter than M4, albeit smaller, and can be spotted with binoculars and the naked eye under good sky conditions.

A digital map of the Rho Ophiuchi Complex. Credit: Stellarium Web

Lastly, if you have an astrophotography set up, capture the Cat’s Paw Nebula near the stinger of Scorpius. You can also capture the Rho Ophiuchi cloud complex in the nearby constellation Ophiuchus. Brilliant Antares can be found at the center of this wondrous structure.

Manaiakalani

While many cultures tell tales of a ‘scorpion’ in the sky, several Polynesian cultures see the same stars as the demigod Māui's fishhook, Manaiakalani. It is said that Māui didn’t just use his hook for giant fish in the sea, but to pull new islands from the bottom of the ocean. There are many references to the Milky Way representing a fish. As Manaiakalani rises from the southeast, it appears to pull the great celestial fish across a glittering sea of stars.

Measure Your Darkness

While you can use smartphone apps or dedicated devices like a Sky Quality Meter, Scorpius is a great constellation to measure your sky darkness with! On a clear night, can you trail the curve of the tail? Can you see the scorpion’s heart? Use our free printable Dark Sky Wheel, featuring the stars of Scorpius on one side and Orion on the other for measurements during cooler months. You can find this resource and more in the Big Astronomy Toolkit.

#night sky notes #kuiper kat writes #astronomy #stargazing #scorpius #constellations

June’s Night Sky Notes: Seasons of the Solar System

by Kat Troche of the Astronomical Society of the Pacific

Here on Earth, we undergo a changing of seasons every three months. But what about the rest of the Solar System? What does a sunny day on Mars look like? How long would a winter on Neptune be? Let’s take a tour of some other planets and ask ourselves what seasons might look like there.

Martian Autumn

Although Mars and Earth have nearly identical axial tilts, a year on Mars lasts 687 Earth days (nearly 2 Earth years) due to its average distance of 142 million miles from the Sun, making it late autumn on the red planet. This distance and a thin atmosphere make it less than perfect sweater weather. A recent weather report from Gale Crater boasted a high of -18 degrees Fahrenheit for the week of May 20, 2025.

Credit: NASA/JPL-Caltech

Seven Years of Summer

Saturn has a 27-degree tilt, very similar to the 25-degree tilt of Mars and the 23-degree tilt of Earth. But that is where the similarities end. With a 29-year orbit, a single season on the ringed planet lasts seven years. While we can’t experience a Saturnian season, we can observe a ring plane crossing here on Earth instead. The most recent plane crossing took place in March 2025, allowing us to see Saturn’s rings ‘disappear’ from view.

A Lifetime of Spring

NASA Hubble Space Telescope observations in August 2002 show that Neptune's brightness has increased significantly since 1996. The rise is due to an increase in the amount of clouds observed in the planet's southern hemisphere. These increases may be due to seasonal changes caused by a variation in solar heating. Because Neptune's rotation axis is inclined 29 degrees to its orbital plane, it is subject to seasonal solar heating during its 164.8-year orbit of the Sun. This seasonal variation is 900 times smaller than experienced by Earth because Neptune is much farther from the Sun. The rate of seasonal change also is much slower because Neptune takes 165 years to orbit the Sun. So, springtime in the southern hemisphere will last for several decades! Remarkably, this is evidence that Neptune is responding to the weak radiation from the Sun. These images were taken in visible and near-infrared light by Hubble's Wide Field and Planetary Camera 2. Credit: NASA, L. Sromovsky, and P. Fry (University of Wisconsin-Madison)

Even further away from the Sun, each season on Neptune lasts over 40 years. Although changes are slower and less dramatic than on Earth, scientists have observed seasonal activity in Neptune’s atmosphere. These images were taken between 1996 and 2002 with the Hubble Space Telescope, with brightness in the southern hemisphere indicating seasonal change.

As we welcome summer here on Earth, you can build a Suntrack model that helps demonstrate the path the Sun takes through the sky during the seasons. You can find even more fun activities and resources like this model on NASA's Wavelength and Energy activity.

#night sky notes #stargazing #astronomy #kuiper kat writes #nasa #mars #neptune

April’s Night Sky Notes: Catch the Waves!

by Kat Troche of the Astronomical Society of the Pacific

The Electromagnetic Spectrum

If you’ve ever heard the term “radio waves,” used a microwave or a television remote, or had an X-ray, you have experienced a broad range of the electromagnetic spectrum! But what is the electromagnetic spectrum? According to Merriam-Webster, this spectrum is “the entire range of wavelengths or frequencies of electromagnetic radiation extending from gamma rays to the longest radio waves and including visible light.” But what does that mean? Scientists think of the entire electromagnetic spectrum as many types of light, only some that we can see with our eyes. We can detect others with our bodies, like infrared light, which we feel as heat, and ultraviolet light, which can give us sunburns. Astronomers have created many detectors that can "see" in the full spectrum of wavelengths.

This illustration shows the wavelength sensitivity of a number of current and future space- and ground-based observatories, along with their position relative to the ground and to Earth’s atmosphere. The wavelength bands are arranged from shortest (gamma rays) to longest (radio waves). The vertical color bars show the relative penetration of each band of light through Earth’s atmosphere. Credit: NASA, STScI

Telescope Types

While multiple types of telescopes operate across the electromagnetic spectrum, here are some of the largest, based on the wavelength they primarily work in:

Radio: probably the most famous radio telescope observatory would be the Very Large Array (VLA) in Socorro County, New Mexico. This set of 25-meter radio telescopes was featured in the 1997 movie Contact. Astronomers use these telescopes to observe protoplanetary disks and black holes. Another famous set of radio telescopes would be the Atacama Large Millimeter Array (ALMA) located in the Atacama Desert in Chile. ALMA was one of eight radio observatories that helped produce the first image of supermassive black holes at the center of M87 and Sagittarius A* at the center of our galaxy. Radio telescopes have also been used to study the microwave portion of the electromagnetic spectrum.

Infrared: The James Webb Space Telescope (JWST) operates in the infrared, allowing astronomers to see some of the earliest galaxies formed nearly 300 million years after the Big Bang. Infrared light allows astronomers to study galaxies and nebulae, which dense dust clouds would otherwise obscure. An excellent example is the Pillars of Creation located in the Eagle Nebula. With the side-by-side image comparison below, you can see the differences between what JWST and the Hubble Space Telescope (HST) were able to capture with their respective instruments.

NASA’s Hubble Telescope captured the Pillars of Creation in 1995 and revisited them in 2014 with a sharper view. Webb’s infrared image reveals more stars by penetrating dust. Hubble highlights thick dust layers, while Webb shows hydrogen atoms and emerging stars. You can find this and other parts of the Eagle Nebula in the Serpens constellation. Credit: NASA, ESA, CSA, STScI, Hubble Heritage Project (STScI, AURA)

Visible: While it does have some near-infrared and ultraviolet capabilities, the Hubble Space Telescope (HST) has primarily operated in the visible light spectrum for the last 35 years. With over 1.6 million observations made, HST has played an integral role in how we view the universe. Review Hubble’s Highlights here.

The Crab Nebula, located in the Taurus constellation, is the result of a bright supernova explosion in the year 1054, 6,500 light-years from Earth. Credit: X-ray: NASA/CXC/SAO; Optical: NASA/STScI; Infrared: NASA/JPL/Caltech; Radio: NSF/NRAO/VLA; Ultraviolet: ESA/XMM-Newton

X-ray: Chandra X-ray Observatory was designed to detect emissions from the hottest parts of our universe, like exploding stars. X-rays help us better understand the composition of deep space objects, highlighting areas unseen by visible light and infrared telescopes. This image of the Crab Nebula combines data from five different telescopes: The VLA (radio) in red; Spitzer Space Telescope (infrared) in yellow; Hubble Space Telescope (visible) in green; XMM-Newton (ultraviolet) in blue; and Chandra X-ray Observatory (X-ray) in purple. You can view the breakdown of this multiwavelength image here.

Try This At Home

Even though we can’t see these other wavelengths with our eyes, learn how to create multiwavelength images with the Cosmic Coloring Compositor activity and explore how astronomers use representational color to show light that our eyes cannot see with our Clues to the Cosmos activity.

#night sky notes #april 2025 #electromagnetic spectrum #wavelengths #radio astronomy #visible light #infrared astronomy #jwst #hubble #chandra #kuiper kat writes

thehikingastronomer

"Quite simply and astonishingly, this is dismantling the National Park Service as we know it, ranger by ranger and brick by brick." - Theres

34 National Park visitor centers and offices, several Geological Survey offices and stations, and dozens of other BLM and Department of the Interior offices and centers are being shut down.

They are coming for the forests and parks. They actively want to destroy the purest things contained within the United States.

#national parks #nps #usgs #united states

March’s Night Sky Notes: Messier Madness

by Kat Troche of the Astronomical Society of the Pacific

What Are Messier Objects?

During the 18th century, astronomer and comet hunter Charles Messier wanted to distinguish the ‘faint fuzzies’ he observed from any potential new comets. As a result, Messier cataloged 110 objects in the night sky, ranging from star clusters to galaxies to nebulae. These items are designated by the letter ‘M’ and a number. For example, the Orion Nebula is Messier 42 or M42, and the Pleiades are Messier 45 or M45. These are among the brightest ‘faint fuzzies’ we can see with modest backyard telescopes and some even with our eyes.

Stargazers can catalog these items on evenings closest to the new moon. Some even go as far as having “Messier Marathons,” setting up their telescopes and binoculars in the darkest skies available to them, from sundown to sunrise, to catch as many as possible. Here are some items to look for this season:

M44 in Cancer and M65 and 66 in Leo can be seen high in the evening sky 60 minutes after sunset. Credit: Stellarium Web

Messier 44 in Cancer: The Beehive Cluster, also known as Praesepe, is an open star cluster in the heart of the Cancer constellation. Use Pollux in Gemini and Regulus in Leo as guide stars. A pair of binoculars is enough to view this and other open star clusters. If you have a telescope handy, pay a visit two of the three galaxies that form the Leo Triplet - M65 and M66. These items can be seen one hour after sunset in dark skies.

Locate M3 and M87 rising in the east after midnight. Credit: Stellarium Web

Messier 3 Canes Venatici: M3 is a globular cluster of 500,000 stars. Through a telescope, this object looks like a fuzzy sparkly ball. You can resolve this cluster in an 8-inch telescope in moderate dark skies. You can find this star cluster by using the star Arcturus in the Boötes constellation as a guide.

Messier 87 in Virgo: Located just outside of Markarian’s Chain, M87 is an elliptical galaxy that can be spotted during the late evening hours. While it is not possible to view the supermassive black hole at the core of this galaxy, you can see M87 and several other Messier-labeled galaxies in the Virgo Cluster using a medium-sized telescope.

Locate M76 and M31 setting in the west, 60 minutes after sunset. Credit: Stellarium Web

Messier 76 in Perseus: For a challenge, spot the Little Dumbbell Nebula, a planetary nebula between the Perseus and Cassiopeia constellations. With an apparent magnitude of 12.0, you will need a large telescope and dark skies. You can find both M76 and the famous Andromeda Galaxy (M31) one hour after sunset, but only for a limited time, as these objects disappear after April. They will reappear in the late-night sky by September.

Plan Ahead

When gearing up for a long stargazing session, there are several things to remember, such as equipment, location, and provisions:

Do you have enough layers to be outdoors for several hours? You would be surprised how cold it can get when sitting or standing still behind a telescope!

Are your batteries fully charged? If your telescope runs on power, be sure to charge everything before you leave home and pack any additional batteries for your cell phone. Most people use their mobile devices for astronomy apps, so their batteries may deplete faster. Cold weather can also impact battery life.

Determine the apparent magnitude of what you are trying to see and the limiting magnitude of your night sky. You can learn more about apparent and limiting magnitudes with our Check Your Sky Quality with Orion article.

When choosing a location to observe from, select an area you are familiar with and bring some friends! You can also connect with your local astronomy club to see if they are hosting any Messier Marathons. It’s always great to share the stars!

You can see all 110 items and their locations with NASA’s Explore the Night Sky interactive map and the Hubble Messier Catalog, objects that have been imaged by the Hubble Space Telescope.

#night sky notes #march 2025 #stargazing #messier marathon #astronomy #kuiper kat writes #messier objects

bloodbending

can’t believe tiktok is actually getting banned, twitter is infested with bots and brainworm-infested musk bots, facebook is king of QAnon, instagram caught the plague from facebook and is dying a slow death in real time… and as the dust settles… only Miss Tumblr is left standing… failing upwards once again

curliestofcrowns

where's that speed skating gif

scarygodmother

thehikingastronomer

Tumblr is the perfect social media and nothing anyone says will change that non-disputable fact. In fact the only reason it has ever struggled is because it is so non-inflammatory as a social media site that it consistently manages to push away all people who have to be mad at the world all the time.

I rarely see viral misinformation.

Minus a few notable hiccups, bots basically steer clear.

AI, to my knowledge, can't gain access.

Staff successfully mocked the shit out of Elon with the two-for-$8 badges you can purchase near-indefinitely in what went down as the greatest fundraising scheme this site ever saw.

Literally the entirety of Tumblr's user base engages in stupid-but-healthy community building site-wide challenges and games every year.

Goncharov.

As long as we forget about the ball pit, Tumblr is the perfect social media.

#long live tumblr I guess?

January’s Night Sky Notes: The Red Planet

by Kat Troche of the Astronomical Society of the Pacific

Have you looked up at the night sky this season and noticed a bright object sporting a reddish hue to the left of Orion? This is none other than the planet Mars! January will be an excellent opportunity to spot this planet and some of its details with a medium-sized telescope. Be sure to catch these three events this month.

Martian Retrograde

Mars entered retrograde (or backward movement relative to its usual direction) on December 7, 2024, and will continue throughout January into February 23, 2025. You can track the planet’s progress by sketching or photographing Mars’ position relative to nearby stars. Be consistent with your observations, taking them every few nights or so as the weather permits. You can use free software like Stellarium or Stellarium Web (the browser version) to help you navigate the night as Mars treks around the sky. You can find Mars above the eastern horizon after 8:00 PM local time.

This mid-January chart shows the path of Mars from September 2024 to June 2025 as it enters and then exits in retrograde motion. Mars appears to change its direction of motion in the sky because Earth is passing the slower-moving Mars in its orbit. Credit: Stellarium

Hide and Seek

On the night of January 13th, you can watch Mars ‘disappear’ behind the Moon during an occultation. An occultation is when one celestial object passes directly in front of another, hiding the background object from view. This can happen with planets and stars in our night sky, depending on the orbit of an object and where you are on Earth, similar to eclipses.

A simulated view of the Moon as Mars begins its occultation on January 13, 2025. Credit: Stellarium

Depending on where you are within the contiguous United States, you can watch this event with the naked eye, binoculars, or a small telescope. The occultation will happen for over an hour in some parts of the US. You can use websites like Stellarium Web or the Astronomical League’s ‘Moon Occults Mars’ chart to calculate the best time to see this event.

Closer and Closer

As you observe Mars this month to track its retrograde movement, you will notice that it will increase in brightness. This is because Mars will reach opposition by the evening of January 16th. Opposition happens when a planet is directly opposite the Sun, as seen from Earth. You don’t need to be in any specific city to observe this event; you only need clear skies to observe that it gets brighter. It’s also when Mars is closest to Earth, so you’ll see more details in a telescope.

Want a quick and easy way to illustrate what opposition is for Jupiter, Saturn, Mars, or other outer worlds? Follow the instructions on our Toolkit Hack: Illustrating Opposition with Exploring the Solar System page using our Exploring Our Solar System activity!

A mosaic of the Valles Marineris hemisphere of Mars projected into point perspective, a view similar to that which one would see from a spacecraft. The mosaic is composed of 102 Viking Orbiter images of Mars. Credit: NASA/JPL-Caltech

Mars has fascinated humanity for centuries, with its earliest recorded observations dating back to the Bronze Age. By the 17th century, astronomers were able to identify features of the Martian surface, such as its ice caps and darker regions. Since the 1960s, exploration of the Red Planet has intensified with robotic missions from various space organizations. Currently, NASA has five active missions, including rovers and orbiters, with the future focused on human exploration and habitation. Mars will always fill us with a sense of wonder and adventure as we reach for its soil through initiatives such as the Moon to Mars Architecture and the Mars Sample Return campaign.

#night sky notes #january 2025 #mars #mars retrograde #occultation #opposition #kuiper kat writes

November's Night Sky Notes: Snowballs from Space

by Kat Troche of the Astronomical Society of the Pacific

If you spotted comet C/2023 A3 (Tsuchinshan-ATLAS) in person, or seen photos online this October, you might have been inspired to learn more about these visitors from the outer Solar System. Get ready for the next comet and find out how comets are connected to some of our favorite annual astronomy events.

Comet Composition

A comet is defined as an icy body that is small in size and can develop a ‘tail’ of gas as it approaches the Sun from the outer Solar System. The key traits of a comet are its nucleus, coma, and tail.

The nucleus of the comet is comprised of ice, gas, dust, and rock. This central structure can be up to 80 miles wide in some instances, as recorded by the Hubble Space Telescope in 2022 – large for a comet but too small to see with a telescope. As the comet reaches the inner Solar System, the ice from the nucleus starts to vaporize, converting into gas. The gas cloud that forms around the comet as it approaches the Sun is called the coma. This helps give the comet its glow. But beware: much like Icarus, sometimes these bodies don’t survive their journey around the Sun and can fall apart the closer it gets.

The most prominent feature is the tail of the comet. Under moderately dark skies, the brightest comets show a dust tail, pointed away from the Sun. When photographing comets, you can sometimes resolve the second tail, made of ionized gases that have been electronically charged by solar radiation. These ion tails can appear bluish, in comparison to the white color of the dust tail. The ion tail is also always pointed away from the Sun. In 2007, NASA’s STEREO mission captured images of C/2006 P1 McNaught and its dust tail, stretching over 100 million miles. Studies of those images revealed that solar wind influenced both the ion and dust tail, creating striations – bands – giving both tails a feather appearance in the night sky.

Comet McNaught over the Pacific Ocean. Image taken from Paranal Observatory in January 2007. Credits: ESO/Sebastian Deiries

Coming and Going

Comets appear from beyond Uranus, in the Kuiper Belt, and may even come from as far as the Oort Cloud. These visitors can be short-period comets like Halley’s Comet, returning every 76 years. This may seem long to us, but long-period comets like Comet Hale-Bopp, observed from 1996-1997 won’t return to the inner Solar System until the year 4385. Other types include non-periodic comets like NEOWISE, which only pass through our Solar System once.

But our experiences of these comets are not limited to the occasional fluffy snowball. As comets orbit the Sun, they can leave a trail of rocky debris in its orbital path. When Earth finds itself passing through one of these debris fields, we experience meteor showers! The most well-known of these is the Perseid meteor shower, caused by Comet 109P/Swift-Tuttle. While this meteor shower happens every August in the northern hemisphere, we won’t see Comet Swift-Tuttle again until the year 2126.

A view of the 2023 Perseid meteor shower from the southernmost part of Sequoia National Forest, near Piute Peak. Debris from comet Swift-Tuttle creates the Perseids. Credit: NASA/Preston Dyches

See how many comets (and asteroids!) have been discovered on NASA’s Comets page, learn how you can cook up a comet, and check out our mid-month article where we’ll provide tips on how to take astrophotos with your smartphone!

#night sky notes #november 2024 #comets #kuiper kat writes #meteor showers

It's been a great week for astronomy in NYC, y'all.

October 10: 🩷 aurorae 💚