MY daughter, Mira, calls it the big boom, the asteroid impact that spelled the death of the dinosaurs. She’s only 3 and still gets scared, or so she says, when it comes up on her favorite Disney dinosaur movie, so I don’t think I will be taking her to "Cosmic Collisions," a new show at the Hayden Planetarium at the American Museum of Natural History.
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Beginning tomorrow, "Cosmic Collisions" will be shown at the Hayden Planetarium daily every 30 minutes, from 10:30 a.m. to 4:30 p.m. (until 7 p.m. on the first Friday of every month), except atnoon and 3 p.m. when the system is maintained. Tickets, which include museum, Rose Centerand planetarium admission, are $22; students and 60+, $16.50; 2 to 12, $13; under 2, free;(212)769-5200.
It’s not that the dinosaur boom, as portrayed here from space, is so scary. But that boom, as the new show makes clear, is only one ― and not the most violent one at that ― of a series of cataclysms that have punctuated and continue to shape the history of the cosmos and the life in it.
Take, for example, the show’s pièce de résistance, in which a small planet sideswipes young Earth, blasting itself and a chunk of Earth into a spray of molten drops shimmering like blobs of mercury. The seats shake, the music screams.
That, scientists say, is how the Moon was formed. Within a month, some of the blobs had cooled and congealed into what would become that friendly pale face in the sky. And we have that whack to thank for our seasons; it knocked Earth off kilter and left its rotation axis tilted with respect to the Sun. Not to mention the tides, caused by the gentle gravitational churning of the Moon.
"Cosmic Collisions," narrated in a calm voice by Robert Redford, pays homage to a new perspective on cosmic history that belies the serene image of lights wheeling peacefully and predictably, stars evolving nearly imperceptibly. Sometimes things happen quickly, out of the blue, and by chance.
Two years in the making, the new show was produced in collaboration with the Denver Museum of Nature and Science; Goto Inc., makers of planetarium projectors in Tokyo; and the Shanghai Science and Technology Museum.
Accompanying the press kit for the show was a list of dozens of scientists and laboratories whose data and supercomputer simulations of everything from the evolution of stars in a cluster to Earth’s magnetic field have formed the basis for the show. When we see the Sun popping off sparks and rays and arcs of incandescent gas like an angry New Year’s Eve ball, we are looking at actual spacecraft images of the Sun.
When, at the end, we sail off into deep space, each of the glowing smudges that we sail past corresponds to a real galaxy mapped by astronomers and painstakingly projected on the big dome around us.
The realism is palpable. After that Moon-forming collision, which comes early in the 20-minute show, I could not endure the image of a rock intruding upon the sky without feeling an anticipatory jolt of adrenaline.
But not all the events depicted here are so literally earthshaking. Some are even microscopic ― protons colliding inside the Sun produce the thermonuclear energy that makes it shine and makes plants grow on Earth.
Others are ethereal. Waves of high-speed particles blasted from the Sun clash soundlessly in the near vacuum of the upper atmosphere with the bubblelike protective structure of Earth’s magnetic field, creating electrical storms that can interfere with radio transmissions and the wavering curtains of light called auroras that decorate the polar nights.
If this show were a symphony, the section on the Sun and the aurora would be a flute solo, but most of us will have come for the crescendos, the planet-cleansing life-changing events, the big booms.
The appearance of something new in the sky, like comets, was often regarded as a bad omen, Mr. Redford says at the beginning, as we watch a dark rock appear in a dark Milky Way-lighted sky over the Adirondacks. It spouts fountains of gas liberated by the Sun’s heat and then spits meteorites from its tail as it passes.
Space, we know, is big and mostly empty. The odds that an asteroid might hit Earth in any given year are only one in a million, Mr. Redford explains. Those odds might sound reassuring until we remember that Earth is 4.5 billion years old.
Tell that to the dinosaurs, whose reign on Earth was abruptly cut off 65 million years ago. It was then, astronomers and geologists have concluded, that a particularly nasty rock appeared in the sky. An asteroid seven miles in diameter, apparently nudged from its normal orbit between Jupiter and Mars, ploughed into the sea near what is now the Yucatán Peninsula of Mexico at 40,000 miles an hour.
From space we see a fireball the size of a continent. The entire Earth, we are told, baked at 500 degrees for an hour. Soot blackened the atmosphere for months, blocking light.
Most of the species on Earth went extinct, but among the survivors were our own ancestors, who might not have gotten the chance to thrive and take over without the demise of everybody else.
The question looms, as we see yet another big rock take aim at Earth (the music swells again), whether we could go the way of the dinosaurs.
Happily, that need not be the case. Given enough warning, according to new studies, we could nudge an incoming asteroid off its collision course by flying a spacecraft by it and giving it a gravitational tug. This is the opposite of the gravitational slingshot effect used to fling spacecraft to the outer solar system by sending them past planets.
And so the new rock passes without the money shot.
There is little we can do, however, about a much bigger collision fated to happen billions of years in the future, when the Milky Way galaxy, in which the Sun and its retinue reside, and the Andromeda galaxy, some two million light years away now but closing in, collide and merge.
Step-by-step computer simulations, in which each second represents 40 million years, show the two spiral galaxies, spinning like jeweled spiders, approach, flow through each other, separate as arms of stars flow gracefully akimbo and then draw together again in a double-yoked embrace, finally merging to become a giant egg-shaped agglomeration billions of years from now.
Because colliding galaxies are so vast, the stars and planets in them would probably just slide by one another, Mr. Redford tells us. What w
ill collide, he says, is the gas and dust that fills the lanes of each galaxy. As the gas compresses and heats, those collisions will produce countless new stars and planets ― new arenas for whatever life might populate the new enlarged galaxy as it sails on into the universe’s golden years.
Whoever lives there someday will be able to thank this collision for the spark of life.
Without such collisions, the Milky Way wouldn’t exist. And probably, neither would we, Mr. Redford says as we cruise outward through the galaxies, a journey I was sorry to end.