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Dark Universe

Explore two of today’s greatest cosmic mysteries—dark matter and dark energy—in a vast, data-fueled starscape of beauty and wonder. Hurtle through deep space and be there for the birth of our own galaxy while exploring never-before-seen visualizations of the invisible matter and forces at work in our Universe.

The Dark Spaces Between Stars—and Between Galaxies—Are Rewriting Everything We Thought We Knew

dark matter
A new, high-resolution algorithm allowed the Kavli Institute of Particle Astrophysics & Cosmology to model what we can’t see: the distribution of dark matter.

Dark Universe is a show like no other, an opportunity to travel to the absolute edge of what we know—or are beginning to suspect—about the 95 percent of the Universe we’re unable to see. Created by a team of scientists, visualization experts, and engineers working within a three-dimensional data set based on roughly 2 million galaxies, Dark Universe escapes the confines of Earth and plunges into two of today’s greatest cosmic mysteries: dark matter and dark energy.

Telling the story of this invisible “stuff” and force—now thought to hold the Universe together and to cause its accelerated expansion—only became possible thanks to tremendous advances in precision cosmology. The field has revealed what Dark Universe curator Mordecai-Mark Mac Low describes as “utterly strange, unexpected things”; using 3D visualizations and real-world scientific data, Dark Universe is the largest and most immersive attempt yet to share that story.

Narrated by renowned astrophysicist and writer Neil deGrasse Tyson (with a soundtrack by composer Robert Miller that brings to life the excitement, wonder, and even fear that accompanies big discoveries), Dark Universe pushes the boundaries of technological storytelling. Hurtle through Jupiter’s atmosphere, sail out to deep space, and be there for the birth of our own galaxy while exploring how our understanding of the Universe has changed over time. Celebrate what we don’t yet know by confronting the invisible matter and energy that astronomers now realize may govern the behavior and fate of the cosmos.

Dark Universe was developed by the American Museum of Natural History, New York (www.amnh.org), in collaboration with the California Academy of Sciences, San Francisco, and GOTO INC, Tokyo, Japan.

All images © AMNH.

We Know It’s Out There, but We Don’t Know What It’s Made Of

Milky Way
Spiral galaxies—like our own Milky Way—helped astronomers realize there’s more to a galaxy than what we can see.

Fast-moving Stars Told Us Something Was Missing

Scientists had long suspected the presence of invisible mass when astronomer Vera Rubin—one of the 1970s’ very few female astronomers—turned her eyes toward spiral galaxies. She and fellow astronomer Kent Ford set out to measure the orbital velocities of stars at the outmost edge of these galaxies, fully expecting them to be circling more slowly than stars closer to the center. Almost immediately, though, they realized something was off. The outside stars were moving just as quickly as their inner counterparts—at speeds that should have sent them flying off into space.

Rubin’s calculations showed that galaxies must be far heavier than the planets, stars, and other observable matter within them added up to. Without a great deal of additional, “dark” mass, galaxies wouldn’t have sufficient gravity to prevent their stars from escaping orbit.

Today, the idea that most of the mass in the Universe is invisible (a short way of saying that it doesn’t radiate or reflect light) is widely accepted by scientists, but that doesn’t mean they’ve got it figured out. Efforts to find and measure dark matter are happening all over the world, as researchers work to answer questions about how it behaves, how it affects other matter and energy in the Universe, and—most puzzling of all—what it’s made of.

Planck Telescope
The Planck space telescope recently completed the most detailed all-sky map of the cosmic microwave background, the afterglow of the Big Bang.

Seeing (and Measuring) the Invisible

Galaxy clusters are one of the best places to look for evidence of dark matter, in part because each cluster generates so much gravity that it actually warps the space around it. Astronomers refer to this warping as “gravitational lensing,” and they can calculate how much gravity (and therefore mass) is involved by measuring the distortion. The answer—which in total is about six times more matter than we can actually see in those clusters—points to the existence of dark matter.

Another way scientists “see” dark matter is through surveys of Cosmic Background Radiation (CBR), a relic of the Big Bang. When mapped by satellites, this radiation provides a picture of how matter was scattered in the first fraction of a second that followed the Big Bang—and it shows there’s significantly more than we can see. The largest CBR survey, done by the Planck satellite in 2013, found that the Universe in fact contains over five times more dark matter than “ordinary” matter.

International Space Station
The International Space Station hosts the Alpha Magnetic Spectrometer, a state-of-the-art particle physics detector.

A World-wide Particle Hunt

Astronomers continue to refine tools capable of discovering where dark matter is and how much of it exists, but the question of what it is has so far proved more difficult to tackle. The most popular candidate these days has been given the dubious name of “WIMP,” which is short for “weakly interacting massive particle.”

While no one’s actually seen a WIMP yet, researchers are hunting for evidence of them in two general ways: by trying to detect them in nature with a wide variety instruments (some in space, others in labs deep underground) and by trying to create them experimentally in supercolliders. Still other scientists are busy investigating alternate candidates, including another hypothetical particle called the “axiom.”

All images © AMNH.

This Gravity-defying Force Is the Greatest Mystery We’ve Never Seen

Mount Wilson
California’s Mount Wilson Observatory was the scene of one of astronomy’s greatest discoveries: In 1929, Edwin Hubble proved that the Universe is expanding.

From Static to Expanding Universe

The 1920s were a time of amazing astronomical progress: Scientists learned not only how to calculate precise distances to faraway stars, but also how to see light emitted by celestial bodies across the blue-green-yellow-red optical spectrum, a technique that gave them new information about each individual light source. Remarkable as each of these measurements was, however, it was the combination of the two that changed astronomy forever.

Astronomers had learned that when an object’s light shifted into the red part of the spectrum, it indicated the object was moving away from the observer. (The larger the shift, the faster the movement.) Based on that technique, they already knew that some stars and nebulae were moving away from Earth, but Edwin Hubble—by adding distance measurements to the mix—discovered a remarkable constant. The farther away a galaxy, he found, the faster it was moving away from us. Like a burst water balloon whose outermost drops travel faster than the rest of its contents, that pattern—the distance-to-speed ratio now called “Hubble’s constant”—was proof that the Universe was expanding.

red shift
The faster a galaxy recedes, the redder its motion vector. The phenomenon, known as “red shift,” led to the discovery of dark energy.

A Cosmic Shock: Expansion Isn’t Slowing Down

The discovery required a huge shift in cosmological thinking—and gave rise to the “Big Bang” theory, since patterns of expansion can be “rewound” backward to an original, exploding source. Seventy years later, scientists were poised to answer a big follow-up question: How quickly was that expansion, which had already been happening for billions of years, slowing down? Gravity, after all, demanded that all the mass in the Universe would act as a kind of brake on its outward momentum.

In 1998, two separate research teams set out to quantify the rate of deceleration, and they were armed with the ability to calculate the distance, speed, and age of celestial bodies more precisely than ever before. A specific type of exploding star, called a type Ia supernova, had been found to have a light so consistent it could be used as a “standard candle”—that is, the relative brightness of a supernova could tell astronomers exactly how near or distant that body is. Distance itself could be understood as a function of age; light from a nearby supernova might take only hundreds of thousands of years to reach us, while truly distant ones took billions. Add in redshift measurements to reveal how quickly various objects were traveling away, and the stage was set: By measuring the rate of expansion at different times in the past, the researchers could calculate the rate at which it was slowing down.

Then came the surprise. Both teams shocked the world—and themselves—by coming up with the same set of findings: the Universe’s expansion wasn’t slowing down at all; it was speeding up. Although individual galaxies were being held together by dark matter, a mysterious force—a force we didn’t even know existed—was dominating the dark spaces in between, pushing back against gravity with enough power to not only to negate but reverse its effects, causing expansion to accelerate.

dark energy
Dark energy—the aspect of space we know least about—dominates the vast majority of our Universe.

The Questions—and the Answers—Are Only Getting Bigger

Scientists call this unknown force “dark energy,” and what we think we know about it amounts to three basic facts: It’s powerful enough to counteract gravity; it appears to be the largest component of our Universe (representing 70 percent of the total combined mass and energy); and it changes nearly everything we thought we knew about space, matter, and how our Universe evolved. Because when astronomers look back at some of the oldest and most distant supernovae known, they see a world in which gravity was once winning—when the momentum from the Big Bang was indeed slowing down. But as expansion pulled galaxies further apart (weakening the gravitational pull between them), dark energy took over, thus shifting the direction—and ultimate fate—of the Universe.

Efforts to figure out what dark energy actually is are underway all over the world, from observatories in the Chilean Andes to telescopes at the South Pole. Today, it’s widely considered the biggest mystery in the world, both literally—in comparison the mere 5 percent of the Universe we can actually see—and as a catalyst sure to drive the next century of big questions and discoveries.

All images © AMNH.

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Dark Universe Programs & Events
Thursday, July 31st

  • Planetarium show - Dark Universe

    Planetarium show - Dark Universe

    10:30 am|11:15 am|12:00 pm|12:45 pm|1:30 pm|2:15 pm|3:00 pm|3:45 pm|4:30 pm

    Nearly everything we know about the Universe has changed: Galaxies are held together by a substance we can’t see, and a force strong enough to counteract gravity is at work in the dark in-betweens. Explore two of today’s greatest cosmic mysteries—dark matter and dark energy—in this vast, data-fueled starscape of beauty and wonder. Hurtle through Jupiter’s atmosphere, sail out to deep space, and be there for the birth of our own galaxy while exploring never-before-seen visualizations of the invisible matter and forces at work in our Universe. Written by best-selling author Timothy Ferris and narrated by renowned astrophysicist Neil deGrasse Tyson, Dark Universe is a celebration of the pivotal discoveries we’ve made thus far—and of the questions that still drive our pursuit of the unknown.

    Dark Universe was developed by the American Museum of Natural History, New York, in collaboration with the California Academy of Sciences, San Francisco, and GOTO Inc., Tokyo, Japan.

    Due to limited seating, show passes are handed out on a first-come/first-served basis—please visit the cart at the planetarium's entrance to pick up your tickets. Our schedule is subject to change, so it's a great idea to confirm your preferred showtime on the day of your visit. Note: Shows may not be appropriate for children 6 and younger, and we regret that we cannot welcome anyone under 4. School and youth groups are required to make advance reservations.

Educator’s Guide

   

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Materials designed to help educators explore the themes of Dark Universe with their students.

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