MessageToEagle.com - Over the years, the spacefaring nations of Earth have sent dozens of probes and
rovers to explore Mars.
Today there are three active satellites circling the red planet while two rovers,
Opportunity and Curiosity, wheel across the red sands below. Mars is dry, barren, and apparently lifeless.
Soon, those assets could find themselves exploring a very different kind of world.
"There is a small but non-negligible chance that Comet 2013 A1 will strike Mars next year in October of 2014,"
says Don Yeomans of NASA's Near-Earth Object Program at JPL. "Current solutions put the odds of impact at 1 in 2000."
The nucleus of the comet is probably 1 to 3 km in diameter, and it is coming in fast, around 56 km/s (125,000 mph).
"It if does hit Mars, it would deliver as much energy as 35 million megatons of TNT," estimates Yeomans.
For comparison, the asteroid strike that ended the dinosaurs on Earth 65 million years ago was about three times as
powerful, 100 million megatons. Another point of comparison is the meteor that exploded over Chelyabinsk, Russia,
in February of 2013, damaging buildings and knocking people down. The Mars comet is packing 80 million times more
energy than that relatively puny asteroid.
An impact wouldn't necessarily mean the end of NASA's Mars program. But it would transform the program-- a
long with Mars itself.
"I think of it as a giant climate experiment," says Michael Meyer, lead scientist for the Mars Exploration
Program at NASA headquarters.
"An impact would loft a lot of stuff into the Martian atmosphere--dust, sand,
water and other debris. The result could be a warmer, wetter Mars than we're accustomed to today."
Meyer worries that solar-powered Opportunity might have a hard time surviving if the atmosphere became opaque.
Nuclear-powered Curiosity, though, would carry on just fine. He also notes that Mars orbiters might have trouble
seeing the surface, for a while at least, until the debris begins to clear.
A direct impact remains unlikely. Paul Chodas of NASA's Near-Earth Object Program stresses that a 1 in 2000
chance of impact means there's a 1999 in 2000 chance of no impact.
"A near-miss is far more likely," he points out.
Even a near miss is a potentially big event. The latest orbit solutions put the comet somewhere within 300,000 km
of the red planet at closest approach. That means Mars could find itself inside the comet's gassy, dusty atmosphere
or "coma." Visually, the comet would reach 0th magnitude, that is, a few times brighter than a 1st magnitude star,
as seen from the Red Planet.
Collision Course? A Comet Heads for Mars
"Cameras on ALL of NASA's spacecraft currently operating at Mars should be able to take photographs of Comet 2013 A1,"
says Jim Bell, a planetary scientist and Mars imaging specialist at Arizona State University.
"The issue with Mars Odyssey and the Mars Reconnaissance Orbiter will be the ability to point them in the right
direction; they are used to looking down, not up. Mission designers will have to figure out if that is possible."
"The issue with the Opportunity and Curiosity rovers will be power for imaging at night," he continues.
"Opportunity is solar powered and so would need to dip into reserve battery power to operate the cameras at night.
Whether or not we will be able to do this will depend on how much power the rover is getting from dusty solar
panels in the daytime. On the other hand, Curiosity is nuclear powered, so it could have better odds at
Researchers will be keenly interested to see how the comet's atmosphere interacts with the atmosphere of Mars.
For one thing, there could be a meteor shower. "Analyzing the spectrum of disintegrating meteors could tell us
something interesting about the chemistry of the upper atmosphere," notes Meyer.
Another possibility is Martian auroras. Unlike Earth, which has a global magnetic field that wraps around
our entire planet, Mars is only magnetized in patches. Here and there, magnetic umbrellas sprout out of the
ground, creating a crazy-quilt of magnetic poles concentrated mainly in the southern hemisphere.
Ionized gases hitting the top of the Martian atmosphere could spark auroras in the canopies of the
Even before the comet flyby was known, NASA had already decided to send a spacecraft to Mars to study the
dynamics of the Martian atmosphere. If the probe, named MAVEN (short for "Mars Atmosphere and Volatile Evolution"),
is launched on time in November 2013, it would reach Mars just a few weeks before the comet in 2014.
However, notes MAVEN's principal investigator Bruce Jakosky of the University of Colorado, the spacecraft
won't be ready to observe the comet when it reaches Mars. "It takes a while to get into our science mapping
orbit, deploy the booms, turn on and test the science instruments--and so on," he explains.
"MAVEN won't be fully operational until perhaps two weeks after the comet passes. There are some effects that
I would expect to linger for a relatively long period--especially if the comet hits Mars--and we will be able
to observe those changes."
Astronomers around the world are monitoring 2013 A1. Every day, new data arrive to refine the comet's orbit.
As the error bars shrink, Yeomans expects a direct hit to be ruled out.
"The odds favor a flyby, not a collision," he says.
The Wandering Stars
In ancient civilizations, people pondered the meanings of the stars, watching for clues to their survival: the beginning of planting and
harvesting times, the seasons, and even portents of danger.
They soon noticed that certain stars didn't stay in place, but wandered amongst the fixed star field.
"The Most Profound Mystery In All Of Science" -
Little is known about this force and its its repulsive gravity, which is causing the expansion of the universe to accelerate.
The riddles of dark matter and cosmic inflation, along with dark energy, these are the three pillars of modern cosmological theory,"
and none of them can be explained with physics that we know," Michael Turner, director of the Kavli Institute for Cosmological Physics says.
Doesn't Secret Dark Matter Exist?
The more scientists study dark matter they know lesser and are not particularly optimistic about their results.
After completing this study, we know less about dark matter than we did before," said Matt Walker, of the Harvard-Smithsonian Center for Astrophysics.
A mysterious and still unknown substance is totally invisible in the Universe and reveals its presence only through its gravitational pull.
Mysteries Of A Dark Universe
Cosmology, the study of the universe as a whole, has been turned on its head by a stunning discovery that the universe is flying apart in all directions at an ever-increasing rate. Is the universe really as we think it should be? Or is nature somehow fooling us?
The astronomers whose data revealed this accelerating universe have been awarded the Nobel Prize for Physics.
Black Holes With No 'Table Manners' Eat Two Courses At Once!
It is still unknown how the supermassive black holes (SMBH) in galaxy centres accrete gas and grow.
Researchers from the University of Leicester (UK) and Monash University in Australia have investigated how some black holes got so big so fast that they are billions of times heavier than the sun.
Mercury Surprises Scientists
On March 17, MESSENGER (MErcury Surface, Space Environment, GEochemistry, and Ranging) completed its one-year primary mission, orbiting Mercury, capturing nearly 100,000 images, and recording data
that reveals new information about the planet's core, topography, and the mysterious radar bright material in the permanently shadowed areas near the poles.
Living Earth Simulator - Supercomputer Predicting The Future
In Douglas Adams book the Hitchhikers Guide to the Galaxy we encounter a machine called Deep Thought. It is the most powerful computer ever built. Deep Thought is capable of answering questions
concerning life, the Universe, and simply everything. Now scientists are planning to create a similar machine. It is called the Living Earth Simulator (LES).
Warp-Speed Planets Are Some Of The Fastest Objects In The Milky Way
Warped planets are some of the fastest objects in the Milky Way and they zoom through space near the speed of light.
Some years ago astronomers were astonished when they they found the first runaway star flying out of our Galaxy at a speed of 1.5 million miles per hour.
The discovery intrigued theorists, who wondered: If a star can get tossed outward at such an extreme velocity, could the same thing happen to planets?
Though the universe is filled with billions upon billions of stars, the discovery of a single variable star in 1923 altered the
course of modern astronomy. And, at least one famous astronomer of the time lamented that the discovery had shattered his world view.
Kepler Will Find Goldilocks Planet Within The Next Two Years
NASA's Kepler spacecraft is discovering a veritable avalanche of alien worlds. Recent finds include planets with double suns, massive
"super-Earths" and "hot Jupiters," and a miniature solar system.
The variety of planets circling distant suns is as wonderful as it is surprising.