Adler Planetarium Announces Opening of Stars Aligned
Header Image: Astrolabium Planum, a book from 1494, features a collection of illustrations corresponding to each degree of the zodiac. Image Credit: Josh Castleberry
On Friday, October 31, the Adler Planetarium’s newest temporary exhibition called Stars Aligned: Tracing the History of Astronomy and Astrology will open to the public. Exploring the connected histories of astronomy and astrology in the early modern period (c.1500-1800), this exhibit will help you understand how people of the past made sense of the world around them.
These two disciplines were once the same practice, but over time, astronomy and astrology took different paths, though tied to a similar purpose, a longing to understand our place in the universe.
Stars Aligned: Tracing The History Of Astronomy And Astrology
Draw back the curtains and get a glimpse into the popularity and practice of astrology in the early modern period through historic instruments and books, helping you piece together how these two disciplines, once intertwined, began to shift. Astronomy, as the mathematical study and charting of celestial bodies, laid the groundwork for scientific discovery. Astrology interpreted those same movements as signs, shaping how people thought about time and fate, and how they used the stars to navigate daily life.
“One of the core missions of the Adler has always been to tell the history of astronomy, to help us understand how where we came from impacts how we study the stars today. Astrology is a crucial part of that history, and it’s so exciting to be able to unpack that story with some of our most unusual and special artifacts,” says Dr. Katie Boyce-Jacino, curator and director of collections at the Adler.
“Approaching the history of astronomy from this angle gives us access to stories and lived experiences that we might not otherwise see. It’s a very human story, of people trying to make sense of the world around them, just like we do today!”
Image Caption: This object is a Northern Indian scroll from 1769 is an astrological calendar for the year, also known as a Hindu Almanac, or Panchānga. Image Credit: Josh Castleberry
Entering the exhibit will feel like entering an astrologer’s home or place of practice from the period, featuring both rarely seen collection pieces and new acquisitions that help tell the history of astrology.
Some featured items include a medical astrology book from the 1600s, a northern Indian scroll and astrological calendar from 1769, a book of zodiac illustrations that dates back to 1494, and the Banneker Almanac from African-American naturalist Benjamin Banneker that offers guidance on topics like planting, astrology, and civic engagement from the year 1795.
A Peek Into The New Exhibit
Before astrology apps, people used panchāngas to plan their lives. Dr. Katie Boyce-Jacino, curator and director of collections, explains how early-modern astrologers used panchāngas, or almanacs, to help people find the perfect day for an event in 18th-century Rajasthan, India.
This beautiful and well-preserved example of a 1769 panchānga is on display in our new exhibit, Stars Aligned.
Learn more about the new exhibit or buy tickets to be among the first to see this temporary exhibition, included with all ticket packages.
Universe-Sized Questions: Dark Matter, Dark Energy, and the Big Bang
Header Image: This is the central region of the Bullet Cluster, which is made of two massive clusters of galaxies. X-rays captured by NASA’s Chandra X-ray Observatory are colored pink. The blue represents dark matter precisely mapped by researchers using JWST. Image credit: NASA, ESA, CSA, STScI, CXC; Science: James Jee (Yonsei University/UC Davis), Sangjun Cha (Yonsei University), Kyle Finner (IPAC at Caltech)
Editor’s Note: This blog was originally published in 2022 and written by Michelle Nichols and Dr. Geza Gyuk and has been updated with more current information.
Dark matter. What is it? Why can’t we see it? And how is it related to dark energy and the Big Bang?
Every day, astronomers at the Adler Planetarium are asked curious questions about the universe. When a fan emailed us asking for an overview of the Big Bang, dark matter, and dark energy, our Director of Astronomy, Dr. Geza Gyuk and Director of Public Observing, Michelle Nichols, did what they do best—explained those extremely complex topics in a way that blew our minds and left us screaming follow-up questions for days.
Read on to learn about dark matter, dark energy, and the Big Bang, directly from the Adler Planetarium experts! Before you dive into the heavy science and distinction between dark matter and dark energy, take a look at our easily digestible overview of dark matter.
Dark Matter And Dark Energy
“Then Nearly 14 Billion Years Ago Expansion Started, Wait…”
Let’s start by describing the expansion of the universe. The expansion is frequently described as an expansion *into* something, sort of like an explosion, where the space is preexisting and matter is flung “out” into the space. This is not what is happening. Instead, the expansion of the universe is really an expansion of space itself. The distances between distant galaxies get larger. The s p a c e between objects physically increases like rubber when stretched.
That’s the key insight of Einstein’s Theory of General Relativity: space and time are dynamic things that can be stretched and twisted. They are not just stages on which physics and history play out.
If everything is expanding, then why do we notice it? After all, if we were getting larger and our measuring devices were also increasing in size, how could we measure that the distance to faraway galaxies is increasing? The answer is that physical objects, like people and planets and stars and solar systems and even galaxies, are “bound.” That is, they are held together by a force. In the case of people, we are held together by electromagnetism (as chemistry). For a solar system, or the Milky Way Galaxy, or the bound system of the Milky Way Galaxy plus the Andromeda Galaxy, that force is gravity.
Key Point: These electromagnetic forces or the gravitational force over smaller distances is “stronger,” in a certain sense, than the force of the expansion of the universe would be at smaller distances.
What does that mean? The universe increases in size over time, but bound objects and bound systems do not. Therefore, we only see this expansion as increasing distances between far-flung galaxies. And because our “rulers” are bound, we can use them to measure the ever-increasing space between galaxies.
The Big Bang (And Balloons)
The best analogy we can give, without resorting to the equations themselves, is to visualize the universe as the “surface” of a very large rubber balloon.
A Large Rubber Balloon = The Universe
Bound objects within the universe are like regions of the balloon that are glued. The rubber can’t expand where it is glued so those objects don’t get bigger. Motion through the universe is analogous to moving along the surface of the balloon. In fact, everything physical happens on the surface. Of course, the universe is three dimensional and the balloon surface is only two dimensional, so we’d have to imagine some sort of hyperballoon to have this completely correct, but the general idea can be understood by imagining a 2-D universe.
Imagine objects living on the surface of the balloon. Now imagine the balloon being inflated. As it is inflated the rubber (space) is stretched and gets bigger. Two spots on the balloon will have a greater length of rubber between them. While in this case the 2-dimensional surface of the balloon does expand outwards into 3-D space, this is not really important. What is important is that the distances on the surface get larger. As time goes on the *area* of the balloon increases. If one projects backwards the area of the balloon must have been much much smaller in the past.
Our universe is like the surface of the balloon, but with one more dimension. Project backwards in time and the *volume* of the universe must have been smaller. Far back in time, the volume of the universe was much much smaller and matter was much more densely packed.
As it turns out, the equations tell us that as the universe expands, not only does the distance between (unbound) objects increase, but the velocity of the objects also decreases (or in the case of photons of light, the energy decreases). Wind the universe’s clock backwards and you’ll find that in the early universe matter was moving very fast and was very close together: it must have been very, very hot and very, very dense. That is the state we call the Big Bang.
Dark Matter (And All Kinds Of Matter) Matters
In fact, the temperatures and the energy per particle were so high that matter behaved very differently in the first few moments of the universe. At tremendous energies, matter can actually be created in the collisions between particles. And that is exactly what we think happened.
Exotic forms of matter were created that are very different from our familiar protons and electrons and neutrons. And, in fact, more of this “exotic” matter was created than normal matter! And it is still here. All around us.
Why can’t we see 90% of the matter that makes up the universe? Because, in our current low-energy universe, it doesn’t interact with normal matter (or even itself!) in any way except gravitationally. To see it would require electromagnetic interaction, and it doesn’t form planets or stars or anything. We call it dark matter because it is dark and does not shine. It clumps together some, but mostly only at distances that are the sizes of galaxies.
So while trillions of particles of dark matter are passing through you every second (yes, right now!) you don’t feel a thing.
Dark Matter: The Fuel Of The Universe
Ok, so dark matter is exotic matter formed in great abundance in the early universe…but what is dark energy? How much of our universe is dark energy? To be completely honest, we don’t know.
How Much Matter Is There In The Universe?
What we know is that by measuring the 3-D distribution and motions of stars and galaxies, and by calculating how gravity works to tug around matter, we can figure out how much normal matter and dark matter there must be in the universe. We do this by comparing what we see in terms of the motions of the visible matter to the calculations. That gives a specific number for how much matter there is in the universe.
Answering The Question: How Much Of Our Universe Is Dark Matter?
Turns out to total about 30% of the so-called “critical density,” with 5% of that being normal matter and 25% being dark matter. But other measurements and calculations show that the density of the universe is pretty close to 100% of the “critical” density.
Anything that can make up that 70% difference in density has to be spread out very widely and can’t cluster and clump at all. In fact, it has to behave very differently from normal matter or even dark matter. Instead of generating an attractive force of gravity, it has a repulsive force of gravity. And that repulsive force ought to be making the expansion rate of the universe speed up instead of slowing down. And that is what we see by looking at the most distant objects in the universe. The universe is expanding faster now than it was 5 billion years ago.
The Evidence For Dark Matter And Dark Energy
Our evidence for dark matter and dark energy is actually very extensive and convincing across many, many measurements of very different types, such as the motions of galaxies and stars and clusters of galaxies, the abundance of particular types of chemical elements, the bending of light from distant galaxies, the patterns of brightness in the microwave background radiation, the distribution of galaxies in space, the speed of recession of supernovae in galaxies out to the edge of the observable universe…all of these are part of the observations that support this consensus cosmological model.
TLDR: Dark Matter Vs. Dark Energy
To Summarize Dark Matter Versus Dark Energy: Dark matter helps normal matter clump up and form galaxies. Dark energy fuels the expansion of the universe. And the early universe was very, very hot and very, very dense. It’s complicated, but explainable!
One of the science goals of the JWST* is to help us refine our understanding of the early universe by imaging and studying distant galaxies. Check out what’s been studied so far!
*In our blogs and other materials, we use the acronym JWST in acknowledgement of the concerns around James Webb’s actions as a NASA agency administrator in the 1960s that contributed to the “Lavender Scare” targeting LGBTQ people in government at the time. If you would like to learn more about this topic, please read this article.
Are Ghosts Made Of Dark Matter?
Is dark matter’s cosmic web like a spider’s web? What happens when an astrophysicist (Dr. Geza Gyuk) and a bedbug expert walk into a panel discussion together? If dark matter could talk, would it tell us humans that it is tired of us telling it what it is?
Watch the Wow! Signal—our lightly educational space comedy sketch show—and laugh along with us as we explore one of the most mysterious mysteries of the universe…dark matter!
What Is Dark Matter? The Spooky Case Of Dark Matter
Header Image: The distorted shapes in the cluster shown here are distant galaxies, from which the light is bent by the gravitational pull of dark matter within the cluster of galaxies. Image Credit: NASA, ESA, M. Postman (STScI), and the CLASH Team
Update: This blog was originally published in 2019 and written by Bianca Anderson and has been updated with more current information by Adler Planetarium Staff.
Halloween is almost here, and as you know, it is a time to celebrate all things spooky, mysterious, and unsettling. And today, we’re taking a look at one of the most unsettling mysteries in the known universe…dark matter.
But what is dark matter?
Sit back, grab some candy, and read on to learn more about why scientists are so perplexed about this common fixture of our universe.
Discovering Dark Matter
The story about how dark matter was discovered reads like an epic mystery novel! In the 1930s, a Swiss astrophysicist named Fritz Zwicky noticed something rather odd about the cluster of galaxies—the Coma Cluster to be exact—that he had been observing.
The galaxies were revolving through the cluster much faster than expected, especially near its outer regions. In fact, the galaxies were moving at such high speeds that the gravity around them should’ve become ineffective at keeping them from drifting away from one another.
Something was keeping the galaxies clustered together.
Zwicky concluded that there had to be an unseen mass that served as a source for additional gravity, keeping the Coma Cluster from dispersing away.
And thus the concept of dark matter was born!
Image Caption: Deep dataset of the Coma galaxy cluster. Image Credit: X-ray: NASA/CXC/Univ. of Chicago, I. Zhuravleva et al, Optical: SDSS
It wasn’t until the 60s and 70s that Zwicky’s observations were further expanded upon, by a young astronomer named Vera Rubin. Using observations made about the orbits of stars within a single galaxy, Rubin was able to conclude that on average, galaxies contain about 10 times as much mass compared to what visible stars account for.
Initially, many astronomers were skeptical of these findings, but eventually, the evidence proved to be so overwhelming that the existence of dark matter became widely accepted in the space-science community.
So, What Is Dark Matter?!
The chilling answer is that we don’t really know.
You see, studying dark matter is a bit of a difficult task due to the fact that it is completely invisible and undetectable with the use of modern-day astronomical instruments.
Adler astronomer Dr. Geza Gyuk has done extensive research regarding dark matter. In the mid-90s, Dr. Gyuk and a group of scientists studied a specific subset of celestial objects called MACHOs.
MACHOs, also known as Massive Compact Halo Objects, are dense objects that emit little to no light. Some examples include: black holes, neutron stars, and brown dwarfs.
Since MACHOs are simultaneously dense and not very luminous, it was originally thought that they could be a serious contender for dark matter.
However, the research conducted by a group of scientists, including Dr. Gyuk, revealed with confidence that MACHOs were most likely not the cause of dark matter. There simply weren’t enough of these objects to account for the huge amounts of unknown mass throughout the universe.
But fret not, although Dr. Gyuk’s MACHOs research didn’t solve the mystery of dark matter, it did help narrow down some of the potential answers. To quote Dr. Gyuk: “If you can rule out the possibilities with an experiment, that’s a good thing too.”
What Is Dark Matter Made Of?
So, if MACHOs aren’t behind dark matter…then what could it be? Well, most scientists believe that dark matter is composed of some sort of “exotic particle” that doesn’t interact with baryonic matter. Baryonic matter is the matter that you and I interact with on a daily basis—the kind of matter that is composed of protons, neutrons, and electrons.
According to Dr. Gyuk, good candidates for dark matter can be found in Weakly Interacting Massive Particles (WIMPs) or axions.
WIMPs and axions are hypothetical particles, consistent with particle physics. They are both types of “Cold Dark Matter.” Cold dark matter is any dark matter that moves very slowly compared to the speed of light.
These proposed WIMPs and axions barely interact with baryonic matter, and they also don’t emit light, making them exceedingly difficult to observe in experiments.
There’s More To Discover With Dark Matter
Nearly a century after Fritz Zwicky’s observations, the search for cold dark matter and WIMPs continues to rage on.
Whether through observing dark matter’s effects on celestial objects or trying to capture a non-baryonic particle in the lab—scientists are as eager as ever in their attempts to solve this mystery.
When asked about the future of dark matter research, Dr. Gyuk had this to say: “We’re hoping that the next generation of experiments will start to detect these non-baryonic particles…If they don’t…people will start to get worried.”
With this in mind, as you celebrate all things spooky—swamp monsters, aliens, and the like—don’t forget about the spookiest beast of them all…dark matter.
Celebrate Dark Matter Day At The Adler
Join us for Dark Matter Day on Sunday, November 2, 2025, from 11:00 am–3:00 pm, and talk to astrophysicists about one of nature’s biggest mysteries–dark matter! Find interactive activities and demonstrations around the museum, along with mini-talks and a one-day-only, dark matter-themed planetarium show!
Adler Skywatch: October 2025
Header Image: A bright full Moon with an orange hue appears surrounded by tree branches in the night sky.
Both the full and the new Moons are highlights of the night sky this month! Here’s what you can see in the sky in October 2025.
Is October’s Full Moon A Super Moon?
This month’s full Moon falls on October 6, making it—by only a day or two—the closest full Moon to last month’s autumnal equinox. By definition, this makes it the harvest Moon for 2025! Usually the harvest Moon takes place in September, but every few years, it falls in October. The last time the harvest Moon occurred in October was in 2020.
Not only is this month’s full Moon the harvest Moon, some also consider it to be a super Moon. While there is no consistent definition of this term, it usually refers to a full (or new) Moon that occurs near the Moon’s perigee—its closest point to Earth in its elliptical orbit. It also means that the full Moon may appear slightly bigger and brighter than usual.
The average distance from Earth to the Moon is just under 239,000 miles, while this month’s full Moon will get less than 225,000 miles from Earth at its closest point. The next two full Moons will also be super Moons—and will get even closer to Earth than this month’s super harvest Moon.
Dark Skies For The Orionid Meteor Shower
This month’s new Moon is also a night-sky highlight, not due to being able to see it, but due to everything else you can see because of the new Moon’s darkness.
Whenever one of the year’s major meteor showers occurs, it’s always recommended to find the darkest sky possible for observing meteors. This month features the Orionid meteor shower, which is caused by debris from Comet Halley. The shower is expected to peak the night of October 22 into the morning of October 23, with a maximum of a dozen or so meteors per hour under very dark, very clear skies. This year, Orionid viewers get a viewing-boost due to the new Moon not lighting-up the night sky!
Planets Visible in October
How To See Saturn
In terms of planetary action this month, Saturn appears in the sky nearly all night long. Early in the month, it’s near the eastern horizon just as the Sun is setting in the west. Late in the month, Saturn is about 15 degrees high in the east-southeast sky at sunset. It gets about 45 degrees high in the southern skies an hour or two before midnight Central Daylight time. The night of October 5 through the early-morning darkness of October 6, it appears less than five degrees below a nearly full Moon. Saturn sets a little south of west before 6:00 am early in the month, and before 4:00 am later in the month.
How To See Jupiter
The planet Jupiter rises in the east-northeast shortly after midnight at the start of the month. It rises a little earlier each night, so that by month’s end it rises around 10:30 pm. At brighter than minus-two magnitude, and getting brighter each night, it outshines the bright stars around it. Around midnight on October 14, Jupiter appears about five degrees to the right of the dark side of a last quarter Moon.
Early in the month, it gets more than 60 degrees high in the southeastern sky before it starts to fade in morning twilight. In the second half of the month, the Sun doesn’t rise until around or after 7:00 am; so Jupiter can be seen later into the morning darkness. It reaches roughly 70 degrees in the southern sky before fading high in the southwest.
How To See Venus
The brightest planet, Venus, rises a little north of east around 5:00 am at the start of the month. About halfway through the month, it rises nearly due-east around 5:30 am and by the end of the month it rises a little south of east around 6:00 am.
It shines just slightly below a bright minus-four magnitude all month long. The morning of October 19, it’s less than five degrees to the left of a very slim waning crescent Moon. The Sun rises about two hours after Venus at the start of the month, and about 90 minutes after Venus rises by the end of the month, so there’s a small window of time to see the planet before the Sun makes viewing difficult.
Can I See Mars and Mercury?
The planets Mars and Mercury appear very close to the setting Sun in October, making them very difficult, if not impossible, to see.
October 2025 Moon Phases
Full Moon: October 6
Last Quarter Moon: October 13
New Moon: October 21
First Quarter Moon: October 29
Please note: these descriptions are for the Chicago area, using Central time.
Subscribe To Skywatch Wednesday This October
Tour the sky with the Adler Planetarium’s Theaters Manager, Nick, in Skywatch Wednesday. Nick uses cutting edge visualizations, NASA images, and astrophotography to show you what you can see in the night sky throughout the year.
Check out Nick’s latest episode to guide you through the autumn night sky. Learn how to see famous fall constellations like Pegasus, Cassiopeia, Cepheus, Andromeda, and Perseus. Nick also explains how to see the Pleiades star cluster, zodiac constellations Sagittarius and Taurus, Saturn with and without its rings, and Moon conjunctions!
Learn From Our Astronomy Educators
Watch recaps of Sky Observers Hangout livestreams this October! Learn how to observe upcoming cosmic happenings, enhance your astrophotography skills, and see celestial objects through a telescope virtually with our astronomy educators.
In the latest episode, Michelle and Hunter tell you everything you need to know about solar maximum—a period of heightened solar activity that we are currently in! Get a live view of the Sun through our telescopes and learn all about how the Sun’s activity and dynamic weather affects us here on Earth.
Understanding Chicagohenge
Header Image: Chicagohenge as seen from West Adams Street. Image Credit: Tim Hara
Update: This blog was originally published in 2020 and written by Bianca Anderson. It is revised each year with updated dates of Chicagohenge and the equinoxes.
Greetings fellow Chicagoans! It is almost that time of year when nature and architecture harmoniously come together to create the phenomenon known as Chicagohenge.
For those who don’t know, Chicagohenge occurs twice a year and happens when the Sun directly lines up with Chicago’s east-west facing streets.
Not only is this event a beautiful sight to behold, but the science behind it is quite interesting—let’s dive in!
About Chicago’s Grid
To fully understand Chicagohenge, you have to be aware of the two main factors that cause it: Chicago’s grid plan and equinoxes.
Let’s first touch on the grid plan that Chicago was built on. A grid plan is when the streets of a city run at right angles to each other forming a (you guessed it) grid!
The present-day Chicago grid system can be attributed to the Public Land Survey System—a surveying method created in 1785 that was used to divide land for selling and settling. But this style of city design has been around since the dawn of civilization and can be found in the ruins of ancient Rome, Greece, and others.
The benefits of a grid plan are numerous. They help make cities more walkable, navigable, and adaptable. Plus they end up resulting in cool astronomical and architectural events (like Chicagohenge)!
Fun fact: Chicago’s streets line up almost perfectly with the cardinal east and west directions on a compass. This in turn, sets up the perfect stage for Chicagohenge to take place.
Chicagohenge is named after the famous prehistoric monument, Stonehenge. A sculpture similar to this familiar giant stone monument, America’s Courtyard, can be found on the right side of the Adler Planetarium when approaching the building. The installation can be used to mark the Sun’s passage through the seasonal equinoxes and solstices.
However, did you know that Stonehenge isn’t actually a henge after all?
@adlerplanet #Chicagohenge is actually a little sus…#Stonehenge #LearnOnTikTok #SpaceScience #Science #Chicago
Now that we’ve got the basics of Chicago’s grid mapped out—let’s dive into the role that equinoxes play in the makings of Chicagohenge.
Equinoxes 101
As the Earth orbits around the Sun, it is also spinning along its tilted axis.
Since the Earth’s axis is tilted, sunlight is not always distributed equally. At any given point, one-half of the Earth is tilted towards the Sun more than the other. As the Earth orbits around the Sun, the part that was tilting away from the Sun begins to be the part that is facing towards the Sun. This is why we have seasons!
There are two times during the year when the Earth’s equator receives most of the sunlight. When this happens, our planet’s Northern and Southern Hemispheres experience equal amounts of day and night—hence the term equinox.
There are two equinoxes each year, one that marks the start of spring (Spring Equinox) and one that marks the end of summer (Autumn Equinox).
During an equinox, the Sun rises and sets directly to the east and west.
Thanks to Chicago’s perfectly lined grid system, the bi-annual equinoxes mark a time when the Sun rises and sets directly in line with Chicago’s east and west streets, causing Chicagohenge!
When is Chicagohenge 2025?
In 2025, Chicagohenge dates fall around March 20–23, 2025 and September 19–22, 2025. The best time to view Chicagohenge is when looking due east or due west around sunset or sunrise on these day(s) leading up to or after the equinoxes.
Friday, September 19, 2025: Sunrise at 6:35 am and sunset at 6:52 pm
Saturday, September 20, 2025: Sunrise at 6:36 am and sunset at 6:50 pm
Sunday, September 21, 2025: Sunrise at 6:37 am and sunset at 6:48 pm
Monday, September 22, 2025: Sunrise at 6:38 am and sunset at 6:47 pm
Best Spots to View Chicagohenge
Finding a place to spot Chicagohenge is a no-brainer! Simply find one of Chicago’s east–west facing streets, pick a spot 5-10 minutes before sunrise or sunset, and enjoy the view.
If you do decide to check it out, snap a pic and tag @adlerplanet and #Chicagohenge on your favorite social media channels! It’s sure to be a sight to behold.
Learn From Our Astronomy Educators
In a previous Sky Observers Hangout episode, our astronomy educators show you how to observe equinox sunrise and sunset alignments in your area and how to photograph Chicagohenge!
Watch the full Chicagohenge episode and subscribe to our YouTube channel to stay up to date on upcoming cosmic happenings and even see celestial objects through a telescope virtually.
Adler Skywatch: September 2025
Header Image: The Sun sets over downtown Chicago during Chicagohenge.
The Sun sets a little earlier each day until almost the end of the year. It reaches a seasonal checkpoint in the sky, bringing with it the beginning of fall. Here’s what you can see in the sky in September, 2025.
The Autumnal Equinox
The autumnal, or vernal, equinox in the Northern Hemisphere occurs on September 22, at 1:19 pm Central Daylight time. It marks the first day of fall and is one of the two points in the year when the Sun appears to cross the celestial equator. Imagine projecting Earth’s equator out into space, dividing the sky into northern and southern halves—that dividing circle is the celestial equator.
On the equinox, the Sun rises roughly due east and sets roughly due west, and the length of daylight hours and nighttime hours are about the same. After the autumnal equinox, the length of nighttime gradually increases each day, until the winter solstice on December 21.
Chicagohenge 2025
On clear days just before, during, and after the autumnal equinox, see if you can spot the famous architectural phenomenon: Chicagohenge. Looking down the east-west-running roads in Chicago and the suburbs, the rising and setting Sun gets framed by buildings and other structures on either side, creating a beautiful sight.
How To See Venus and Jupiter
Like last month, the planets Venus and Jupiter appear not far from each other, low in the east shortly before sunrise. Bright Jupiter rises first, in the east-northeast around 3:00 am at the start of the month, and at about 1:30 am by month’s end. To the left of Jupiter are the bright “twin stars” Pollux and Castor, in the constellation Gemini. Pollux is the brighter of the two stars, but Jupiter is brighter than either star. The morning of September 16, a very slim crescent Moon appears between the planet and the two stars.
In the east-northeast, the dazzling Venus rises a little after 4:30 am at the start of the month and around 5:45 am by month’s end. The two planets are about 20 degrees apart on September 1 and move farther apart until they’re about 50 degrees apart on September 30.
The morning of September 19, a nearly new Moon is in conjunction with Venus. The planet will be barely a quarter of a degree from the lower “horn” of the skinny crescent Moon. You may also see a star about a half degree to the lower right of Venus. That star is Regulus, the brightest star in the constellation Leo.
Winter Stars Make An Appearance
Before sunrise, you may also notice that there are numerous fairly bright stars to the right of Jupiter and Venus, in roughly the same quarter of the sky. Over the next three months, those stars will highlight the winter night sky, including the night’s brightest star, Sirius, in the constellation Canis Major. It shines at nearly -1.5 magnitude.
How To See Saturn
If you don’t want to rise before dawn to see a planet, Saturn appears low in the east by about 9:30 pm at the start of the month, and by about 7:30 pm by the end of the month. It remains brighter than first-magnitude all month long. Saturn is at its nearest approach to Earth for the year this month, and on September 21, Saturn reaches its opposition. When a planet is in opposition, it means that the Earth is directly between it and the Sun.
Around midnight, Saturn gets about halfway up in the southern skies at its highest point. The night of September 7 through the morning of September 8, Saturn appears near a large Moon, barely a day past a full Moon.
Early in the month, it fades away low in the west-southwest as morning twilight brightens the sky. But in the latter half of the month, if you have a clear view to the western horizon, you may be able to see Saturn setting before the sky becomes too bright.
Moon Phases
There is a total lunar eclipse occurring this month, the night of the full corn Moon on September 7, however, it won’t be visible from the continental United States.
Full Moon: September 7
Last Quarter Moon: September 14
New Moon: September 21
First Quarter Moon: September 29
Please note: these descriptions are for the Chicago area, using Central time.
Subscribe To Skywatch Wednesday This September
Tour the sky with the Adler Planetarium’s Theaters Manager, Nick, in Skywatch Wednesday. Nick uses cutting edge visualizations, NASA images, and astrophotography to show you what you can see in the night sky throughout the year.
Check out Nick’s latest episode, learn how to see the summer triangle and the constellations that make it up. Plus, see zodiac constellations, Scorpius and Sagittarius, along with several Moon and planet conjunctions, and the Milky Way this summer!
Learn From Our Astronomy Educators
Watch recaps of Sky Observers Hangout livestreams this September! Learn how to observe upcoming cosmic happenings, enhance your astrophotography skills, and see celestial objects through a telescope virtually with our astronomy educators.
In the latest episode, Michelle and Hunter tell you everything you need to know about solar maximum—a period of heightened solar activity that we are currently in! Get a live view of the Sun through our telescopes and learn all about how the Sun’s activity and dynamic weather affects us here on Earth.
The Adler Planetarium Mourns the Loss of Captain James A. Lovell Jr.
Header Image: Captain James A. Lovell, Jr. Official Portrait Taken at the Adler Planetarium in 2018.
The Adler Planetarium mourns the loss of American hero, former NASA Astronaut, and Adler Life-Trustee Captain James A. Lovell Jr. who died yesterday, August 7, 2025, at the age of 97.
Captain Lovell, a part of the Adler family for many years, was instrumental in making the Adler a community engagement center for space science. In 2007, Lovell became an Adler Trustee and co-chaired the most successful fundraising campaign in Adler’s history. The campaign raised funds for new exhibitions, theater experiences, education, and research. Captain Lovell worked tirelessly as an advocate for public science education and was a very dear friend of the Adler. He will be greatly missed.
The following is a statement from Interim Adler Planetarium President & CEO Audris Wong:
“On behalf of the Adler Planetarium, I express our heartfelt condolences to the entire Lovell family. A true American hero, James A. Lovell Jr.’s life story demonstrates perseverance, commitment, and hard work. For multiple decades, the Adler has been honored to work closely with Jim. In addition to being a Trustee, he generously contributed his space artifacts and passionately advocated for improving science engagement. Jim’s personal stories of space exploration have inspired millions of visitors. Captain Lovell was a naval hero, space pioneer, and successful business leader, but it is his role as a champion for science education and his commitment to motivating the next generation of explorers that will be his enduring legacy at the Adler Planetarium.”
A Lifelong Connection
In the early 1940s, when Captain Lovell was a young boy, he found himself wandering the halls of the Adler Planetarium looking for parts for his new hobby of rocketry. Instead, what he found was a deep inspiration for the concepts of astronomy and space exploration. This passion led him to an extraordinary career with NASA as one of the first astronauts of the early crewed-space flights of Gemini 7, Gemini 12, Apollo 8, and the fateful Apollo 13.
In 2005, he generously donated many of his personal effects from his storied career to the Adler’s collection, enabling guests a unique glimpse into the lives of those that took America’s first steps into space, which Jim was quick to point out, included the talented colleagues and supportive family members who were instrumental to every success. You can find these personal effects in our Mission Moon exhibit, telling the story of the space race through Lovell’s eyes.
In honor of Captain Lovell’s 90th birthday in 2018, the Adler honored him through a Letters to Lovell campaign. People young and old throughout the world wrote to express how Captain Lovell inspired them. The heartwarming letters were featured in the Mission Moon gallery and presented to him when he was honored with a lifetime achievement award at the annual Celestial Ball gala.
In celebration of Captain Lovell’s life, the Adler is relaunching Letters to Lovell. We invite guests to share how he has inspired them by visiting our Mission Moon gallery and writing him a letter, or submitting one to [email protected]. All letters will be shared with Jim’s family to cherish forever.
An Eye To The Future: The James A. Lovell Legacy Fund
In October of 2024, the Adler launched the James A. Lovell Legacy Fund. The new endowment, spearheaded by Captain Lovell and his family, will help the Adler support infrastructure needs, and continue to inspire the next generation of explorers into the future. More than $3.4 million has been committed to seed the fund.
At the Adler, we want each person who walks through the doors of our iconic art-deco building to find what Captain Lovell found here: a universe, a community, and an irresistible call to explore whatever captures their imagination. Everyone should know the Adler as a safe place to try and fail and try again, an approach Jim Lovell successfully demonstrated throughout his life. We’ll all face unexpected challenges and even failures; it’s what we make of these moments—how we readjust, learn, and grow that matters. The Lovell Legacy Fund will help the Adler continue to provide these unexpected, inspirational moments.
Learn more about the Lovell Legacy Fund, or make a donation.
More About Captain James A. Lovell, Jr.
Captain Lovell is best known for his courageous role as commander of the Apollo 13 mission, which suffered a critical failure en route to the Moon, but was brought back safely to Earth by efforts of the crew and mission control. He also piloted Apollo 8, the first Apollo mission to enter lunar orbit. He is one of only 24 people to have flown to the Moon, and the only one to have flown there twice without making a landing.
In perhaps his proudest role, he was married to his high school sweetheart, Marilyn Lillie Lovell, for 71 years before she preceded him in death. Together, they had four children, eleven grandchildren, and seven great grand-children. Captain Lovell attended the University of Wisconsin-Madison, graduated from the United States Naval Academy, the University of Southern California Aviation Safety School, and Harvard Business School’s Advanced Management Program. He is a recipient of the Congressional Space Medal of Honor and the Presidential Medal of Freedom.
On November 20, 2019, Adler Planetarium staff interviewed Captain Lovell about his memories and thoughts looking back at his exciting career. Hear his stories.
The Adler Planetarium Appoints Elizabeth Babcock as President and Chief Executive Officer
Header image: Headshot of Elizabeth C. Babcock
The Adler Planetarium announced today the appointment of Elizabeth C. Babcock, PhD as its next President and Chief Executive Officer. Babcock’s appointment follows a comprehensive six-month global search led by a committee of Adler’s trustees, made up of prominent business and civic leaders, in partnership with Russell Reynolds Associates. The committee’s recommendation was unanimously approved by the Board of Trustees.
“On behalf of the Board, it is my pleasure to welcome Elizabeth back to Chicago to lead the Adler,” said Nancy Gerrie, Chair of the Board of Trustees. “Elizabeth is a non-profit leader of national distinction, an accomplished fundraiser, and a dedicated scientific educator. We are confident her expertise and vision will profoundly shape the Adler’s future. I look forward to seeing the continued positive impact of the Adler in our community under her leadership.”
Babcock joins the Adler with extensive experience in a wide array of leadership roles. Most recently, she served as the Founding Director of the Smithsonian American Women’s History Museum in Washington D.C., where she laid the groundwork for a landmark multimillion dollar campaign. Prior to her time at the Smithsonian, Babcock was President and CEO of Forever Balboa, the city of San Diego’s private partner stewarding a 1,200-acre urban park. She also held the key senior role at the California Academy of Sciences in San Francisco as the Chief Public Engagement Officer and Roberts-Wilson Dean of Education. There, she directed the Morrison Planetarium and Science Visualization Studio and public-facing programs that reached over 20 million learners worldwide and secured significant philanthropic support for science education. In Chicago, Babcock previously served as Vice President of Education and Library Collections at the Field Museum of Natural History.
“I am honored to join the Adler Planetarium as its next President and CEO,” said Babcock. “This is an extraordinary moment to lead an historic institution, one that inspires us with daily discoveries about the cosmos and the universe we inhabit together. I aim to build upon the Adler’s exceptional record in space science education, community engagement, and collaboration as we prepare to celebrate our centennial in 2030, and beyond.”
Gerrie continued, “We are also deeply grateful to Audris Wong, who has provided steady leadership as Interim CEO over the past several months. Audris will return to her role as Vice President of Finance and Administration following Elizabeth’s arrival on October 6th. With such a strong leadership team and dedicated staff, the Adler is well-prepared for the exciting years ahead.”
Support America’s First Planetarium
Located on Chicago’s lakeshore, the museum typically hosts more than half a million visitors each year and reaches millions more through youth STEAM programs, neighborhood skywatching events, people-powered research, and other outreach efforts. Today, the Adler is bringing our unique approach—scientific exploration rooted in community and connection—to guests from around the world who can enjoy the digital Adler from their own homes, libraries, schools or offices.
Donate today and help us continue to bring educational space programming to everyone, everywhere as we embark on this new chapter!
Reading List: The Best Space Science And Astronomy Books
Header Image: Assigned Reading graphic displaying books.
As adults, we rarely get assigned reading. Which, honestly…is a SHAME. The thrill of earning prizes like a personal pan Pizza Hut pizza or holographic stickers from the local public library for completing your summer reading was unmatched.
For our forever learners, we wanted to make this blog extra special for you.
Reading List: Best Astronomy Books
Usually, books are paired best with a cup of tea or coffee, but these suggestions pair best with binoculars and/or a clear night sky. Preferably both!
We asked our staff to hand-pick a few of their personal favorite space-themed books. We hope you find one of your new favorite reads below.
A Book For People Who Love Stargazing
365 Starry Nights by Chet Raymo
These 365 illustrated essays will show you how astronomers see the stars. You’ll learn how to use your own observations to calculate a star’s age, brightness, and distance from Earth.
“As a total astronomy beginner, this book has been super helpful to build my familiarity with the night sky,” Teen Programs Manager, Lauren Wisbrock, states.
Assigned by the Adler’s Director of Public Observing, Michelle Nichols.
A Book For People Who Are Obsessed With Space Exploration
The Mission: A True Story by David W. Brown
A never-before-told story of modern space exploration, and the inner lives of scientists who study the solar system’s mysterious outer planets.
“A great look at the behind-the-scenes of what it actually takes to get a space mission off the ground,” Mike Smail, said.
Assigned by Senior Director of Theaters & Visualization, Mike Smail.
A Book For People Who Can’t Wait To Colonize Mars
Packing For Mars by Mary Roach
Are you ready to unpack the scientific side of space travel, even the gross bodily functions like going to the bathroom in space? Hold on to your seats (because there’s no gravity in space).
“Packing For Mars shines a light on the craziness of space travel, such as how space affects human bodily functions and how the mental and physical aspects of spaceflight are tested,” Dr. Mike Zevin, states.
Assigned by Adler Astronomer, Dr. Michael Zevin.
A Book For People Who Are Interested In The History Of Astronomy and Astrology
A Scheme Of Heaven: The History of Astrology And The Search For Our Destiny In Data by Alexander Boxer
Perfect for any history or data science nerd, dive into the surprising history and science of astrology, civilization’s first system of algorithms, from Babylon to the present day. Horoscopes were once a cutting-edge scientific tool, and astrology was a vast, technological project—spanning continents and centuries—that foreshadowed our data-driven world today.
Assigned by the Senior Manager of Facilitations, Ani Schmidt.
A Book For People Interested In Light Pollution And Environmental Justice
The Darkness Manifesto by Johan Eklöf
A timely and captivating look at the hidden impact of light pollution. Darkness may not be as scary as we think, leaving you with an understanding of the impact of light pollution on wildlife with an ecological and evolutionary perspective.
“The chapters are super quick, focused, and digestible,” said Lauren Wisbrock.
Assigned by Adler’s Teen Program Manager, Lauren Wisbrock.
A Book For People Who Are Interested in Mind-Blowing Astrophysics
The Fabric Of The Cosmos by Brian Greene
Greene breaks down the brain-melting science of space and time for general audiences. If you’ve heard of relativity but you don’t actually know what it is, this book is for you.
“I read this book when I was in graduate school for creative writing and spent the next several months screaming in everyone’s face about how time is an illusion,” said Aubrey Henretty.
Assigned by the Adler’s Manager of Science Content and Communication, Aubrey Henretty.
A Book For People Who Love Celebrating Anniversaries
100 Years of Planetaria: 100 Stories of People, Places, and Devices
It’s been 100 years since the first planetarium captured the public’s imagination! To celebrate, this book shares 100 stories, each told by an expert, scientist, historian, or planetarium professional, some of whom may be familiar to readers as former and current staff of the Adler Planetarium.
“The planetarium is the original immersive environment. Before Sphere, before Immersive Van Gogh, before virtual reality there were planetariums. Created 100 years ago to allow people to visualize the motions of the celestial bodies in the sky, the planetarium has always been a physically and emotionally transportive experience,” Mike Smail, states.
Assigned by Senior Director of Marketing, Erin Wilson.
Never Run Out of Space
As your spaced-out summer transitions into a fall-out fall, keep up with our cosmic shenanigans at the Adler. Get your fill of mildly-educational and highly-entertaining space hijinks straight to your inbox, all year long.
In our bi-weekly newsletter, Space From Home, we give you the rundown on breaking space news, share fun things to click on, and keep you up-to-date on all things Adler.
Adler Skywatch: August 2025
Header Image: A long-exposure image of shooting stars from the Perseids meteor shower leaving long white streaks across the dark sky, with the Milky Way galaxy visible between them.
A major annual meteor shower peaks, and the sky’s two brightest planets have a close encounter this month. Here’s what you can see in the sky in August, 2025!
The Perseids Meteor Shower
The Perseids—the most reliable summertime meteor shower—peak this month! Named for the constellation Perseus, the Hero, the meteors in this shower all trace back to its radiant point in Perseus.
Like many other annual meteor showers, the Perseids are caused by debris left in space by a comet and can appear anywhere in the sky. There are a few other annual showers that may display as many, or more, meteors than the Perseids, but those take place in wintertime.
How To See The Perseids Meteor Shower
Technically the Perseids meteor shower became active in mid-July; but this year, its predicted peak starts the evening of August 12 through the early-morning darkness of August 13.
Unfortunately, the waning-gibbous Moon rises that night shortly before 10:00 pm, so its glare will block fainter Perseid meteors from view. At the shower’s peak, around 50–75 Perseid meteors per hour are expected under very dark, very clear skies—which will be hard to achieve when the Moon is up. Under moonlit and light-polluted skies, expect to see far fewer than that, maybe only a dozen or so. Face east, look up, and settle in for at least 15–20 minutes to give your eyes a chance to adjust to the darkness. Watch for sporadic quick streaks of light—those are meteors!
Tips For Seeing The Perseids In 2025
The shower is active through late in the month, so one viewing suggestion for seeing more is to look for meteors a day or two (or three!) after the peak, when the Moon rises later. If you go out to look before the Moon rises, you have a better chance of seeing more, and fainter, meteors. There will be fewer meteors, overall, past the peak date, but the few hours of darker skies might help you see some.
Another technique to spot the Perseids is to put the Moon at your back—or behind a tree or building—to help minimize its bright glare.
Planet-Spotting In August, 2025
Venus and Jupiter are shining bright with a few close conjunctions throughout the month. Saturn will be easily spotted in the early-evening, with Mars and Mercury hiding not too far from the Sun setting and rising Sun.
Venus And Jupiter Conjunctions
The brilliant planet Venus (at almost minus-4 magnitude) and the slightly less-bright planet Jupiter (at almost minus-2 magnitude) appear near each other during morning twilight this month. They start the month roughly ten degrees away from each other, low in the east-northeast skies.
You’ll spot Venus first, since it’s practically impossible to miss in a clear dark sky. Venus rises at about 3:00 am for most of the month. Jupiter starts the month rising around 3:30 am, but rises a little earlier each morning.
From August 1 through August 11, Venus appears above Jupiter in the sky; but by August 12, Jupiter appears slightly above Venus. This morning, the two planets appear in a close conjunction—less than one degree apart! After August 12, Jupiter moves roughly a degree higher than Venus each morning, so that by month’s end, the two planets are nearly 20 degrees apart.
The morning of August 20, a very slender waning crescent Moon appears between Venus and Pollux, the brightest star in the constellation Gemini.
Where Is Mercury This Month?
At around zero magnitude this month, Mercury is not as eye-catching as either Venus or Jupiter, but it still is quite bright.
The morning of August 15, Mercury appears far enough above the rising Sun to be visible. Look for it about 40 minutes before sunrise, less than ten degrees above the east-northeast horizon.
On August 20, Mercury starts to sink closer to the horizon each day. The morning of August 21, you may be able to make out a sliver of a waning crescent Moon—only two days before a new Moon—just above Mercury. After August 22, Mercury appears barely 14 degrees away from the Sun’s edge and thus will be difficult, if not impossible, to see.
How To See Saturn And Mars
Saturn will be readily visible in the evening sky this August. It rises in the east around 10:30 pm at the start of the month, and around 8:30 pm by month’s end. It’s slightly brighter than first-magnitude all month long, and is in the sky most of the night. Saturn reaches roughly 40 degrees high in the south at its highest, between 2:30 am–4:00 am and fades in the southwest as dawn brightens the sky.
This month, the planet Mars is dimmer than 1.5 magnitude. It sets not quite two hours after the Sun, and is very low in the west-southwest once the Sun does set; so it may be hard to see. Late in the month, Mars very slowly begins to brighten again, but it spends the next several months too close to the Sun for ready visibility.
Moon Phases In August, 2025
First Quarter Moon: August 1
Full Moon: August 9
Last Quarter Moon: August 16
New Moon: August 23
First Quarter Moon: August 31
Please note: these descriptions are for the Chicago area, using Central time.
Subscribe To Skywatch Wednesday This August
Tour the sky with the Adler Planetarium’s Theaters Manager, Nick, in Skywatch Wednesday. Nick uses cutting edge visualizations, NASA images, and astrophotography to show you what you can see in the night sky throughout the year.
Check out Nick’s latest episode, learn how to see the summer triangle and the constellations that make it up. Plus, see zodiac constellations, Scorpius and Sagittarius, along with several Moon and planet conjunctions, the Perseid meteor shower, and even the Milky Way this summer!
Learn From Our Astronomy Educators
Watch recaps of Sky Observers Hangout livestreams this August! Learn how to observe upcoming cosmic happenings, enhance your astrophotography skills, and see celestial objects through a telescope virtually with our astronomy educators.
In the latest episode, Michelle and Hunter tell you everything you need to know about solar maximum—a period of heightened solar activity that we are currently in! Get a live view of the Sun through our telescopes and learn all about how the Sun’s activity and dynamic weather affects us here on Earth.
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