There’s another dwarf planet to add to the list of solar
system bodies thatshare minor
league status with Pluto.
Newly published Hubble Space Telescope pictures show that
the large asteroid Pallas is nearly spherical. In other words the body has enough
gravity to pull itself into ball where all surface features are essentially the
same distance from the core.
This is one criterion for a planet according to the
International Astronomical Union (IAU). Hubble’s sharp view can resolve the disk
of Pallas and shows that it is slightly
egg-shaped, and roughly the width of West Virginia.
What a difference the time of day makes on the moon.
NASA’s
Lunar Reconnaissance Orbiter has re-photographed the Apollo 11 landing site on
the Sea of Tranquility. The first picture released on July 17 showed the long
shadow of the lander because the sun was low in the sky. It was essentially
late afternoon on the moon.
In the new picture the afternoon sun is 28 degrees above the horizon and
the site looks noticeably different with better contrast and brightness.
In particular, you can see the trail of footprints
of the first man on the moon, Neil Armstrong, as he walked to the 100-foot wide
Little West crater for a close-up look.
Last month a reader left a comment on this site wondering
where the “Apollo artifacts” were that I said NASA’s Lunar Reconnaissance
Orbiter (LRO) would photograph.
Well this is the coolest picture to date from LRO that
captures the activities of Apollo astronauts at a moon-landing site. It is
littered with hardware!
But even more intriguing, we see the astronauts' footprints. From LRO's altitude they look like the humble little tracks of small birds across newly fallen snow.
LRO flew over the flat lava plain in western Oceanus
Procellarum where Apollo 12 landed on November 14, 1969. The unmanned Surveyor
3 landed there two years earlier.
The bright red star Betelgeuse in the winter constellation Orion the
Hunter is sure to get a giggle in introductory astronomy college classes. Older
students may remember the 1988 Tim Burton film Beetle Juice with comic Michael
Keaton. And, it’s fun to tell younger students that Betelgeuse is Arabic for “armpit
of the giant” (which is actually a mistranslation).
The latest data from the Very Large Telescope in Chile telescope
show that this star is nothing to laugh at. It is one bad-ass supergiant, with a dragon’s breath plume of gas, and boiling monster bubbles of gas – yuck!
Placed
inside our solar system it would swallow Earth and the other inner planets and
extend all the way out to Jupiter’s orbit. The volume of space such a monster
star engulfs is simply inconceivable. Imagine the sci-fi film: The Star That Ate My Planet!
When I was a kid I loved those board games that let you take
a shortcut to get to the “finish” square first. Everybody's favorite is: “Go directly
to Go and collect $200,” from Monopoly.
An interplanetary shortcut was implied last week when NASA’s
new administrator, astronaut Charles Bolden, said he would like to see humans
venture beyond the moon and onto other destinations in the solar system. The 62
year-old administrator said that he’d like to see humans on Mars within his
lifetime.
Could we get to the Red Planet in the next 25 years? I’d say
only if we sidestep spending all the time and resources to set up a base on the
moon, i.e. “go, past moon, go directly to Mars.”
What I love about NASA conspiracy theorists -- you know
those folks who think we never went to the moon and the Air Force is hiding alien bodies -- is
that they want to have their cake and eat it too.
At a recent convention called, you guessed it, Conspiracy
Con 2009, self-styled Mars sleuth, Andrew Basiago, accused NASA of hiding evidence of Martian
life in photos taken from the rover Spirit.
But I will bet money that when NASA eventually releases images showing manmade artifacts at the Apollo landing sites, to be photographed from the Lunar Reconnaissance
Orbiter (LRO, which will enter lunar orbit tomorrow) conspiracy flakes will accuse NASA of faking the PR pictures.
We’re a nation of science dummies. No more than 25 percent
of Americans are “scientifically savvy and alert,” says public opinion researcher
Jon Miller. Most of the rest of us “don’t have a clue.”
Prime time TV dramas like the upcoming miniseries, Impact,
which will air on ABC-TV the next two Sunday evenings (June 21st and 28th) underscores this
sad state of science cluelessness. The scriptwriter Michael Vickerman (author
of several B-grade sci-fi flicks) is a total ASTRO-101 flunky.
Astronomy’s equivalent of the “Great Pumpkin” from the
Peanuts comic strip is popping up again on Internet traffic. For the sixth year
in a row, an Internet message gone viral predicts that the planet Mars will look as "big as
the full moon" later this year.
Nope, not happening. But in our capricious universe, never say never.
A new computer simulation of the dynamical evolution of the
solar system over the next 5 billion years suggests that our distant descendents
could witness such a sky spectacle, just before the world is destroyed in a
catastrophe of Biblical proportions.
I recently had fun making a baking soda powered tabletop
volcano to the delight of my grandson Leo, who just loves watching the thing
explode. You know, that popular middle school science fair project where vinegar (acetic
acid) neutralizes baking soda and causes it to give off carbon dioxide,
creating pressure that blows the liquid up a toy volcano cone.
But on other planets there may really be volcanoes gushing out water rather than molten rock. And, mud volcanoes that belch out a slurry of
organic-rich material, if not subterranean microbes.
The possible discovery of wet slushy volcanoes on Titan and
Mars, and damp soils, is ratcheting up the possibility of finding extraterrestrial
life. A number of papers were presented last week at the 40th Lunar and
Planetary Science Conference in The Woodlands, Texas.
Cryovolcano
In the frigid outer solar system, where daytime temperatures
are at -300 degrees Fahrenheit or lower, a different type of geology may be taking
place – cryovolcanos. These mountains are suspected of spewing out a Slurpee of ice, propane, butane and other
liquid hydrocarbons.
The best candidate is an area known as Hotei Arcus, thought
not everyone agrees it is really a volcano. Photos on different flybys taken by
the NASA/ESA Cassini orbiter have been interpreted as cryo-lava outflows.
The
lobe-like fingers, each hundreds of feet high, have a shape and thickness
consistent with highly viscous lava on Earth. Like an advancing flow of lava,
the lobes also appear to cut off several small streams apparently carved by
liquid methane.
You need a subterranean heat source close to liquid reservoirs
to spew out this stuff. It’s sort of nature’s recreation of the famous 1952 Miller-Urey
experiment that mixed pre-biotic compounds, such as water, methane and ammonia
(an ideal antifreeze for Titan) to make amino acids – the building block of
life.
Mud Volcanoes
Closer to home, Mars orbiting spacecraft have identified
dozens of mounds in the northern plains that bear a striking
resemblance to mud volcanoes on Earth. High-resolution images reveal small
knobs or patches. They frequently have one or more craters and an irregular
shape.
As on Earth, a mud volcano would form when pressurized gas
and water from as much as several miles down, blows out the surface like a
popped Champaign cork. This shoots out a gooey mess of water, mud, rocks, as
well as methane.
Mud volcanoes would
accomplish what a martian drilling rig would have a tough time doing,
transporting rocks from several miles beneath the martian surface, and placing them
within reach of sample-return rovers.
Microbial life could be flourishing deep below the martian surface,
perhaps driven there as surface conditions became hostile over geologic time. It may be warm enough miles below the surface for water to remain a liquid. The
volcanoes, which may be as young as 10 million years, offered an elevator for
microbes to reach the surface – in a martian twist on the closing chapter of Jules
Verne’s 1864 novel Journey to the Center of The Earth.
Briny Droplets
A highly publicized surprise from NASA’s Mars Phoenix Lander
was the discovery of perchlorates in the planet’s arctic region. Perchlorate is
the stuff used to make rocket fuel and explode fireworks. On Mars these salts
could keep water in a liquid state at temperatures of -160 degrees Fahrenheit.
Pockets of brine might form when the perchlorate mixes with
the water ice that Phoenix found near the north pole. In fact there has been a lively
debate whether Phoenix photographed briny liquid water droplets on the lander legs,
which would have been kicked up by its landing thrusters. Some scientists think they move like a liquid in successive exposures. Others say it’s just
frost.
The perchlorates may explain why the mid 1970s Viking
biology experiments did not find any organic compounds in
the soil. The soil was heated in the Viking biology experiments. Heated perchlorates
release their oxygen and burn up and organic material! So maybe the
release of carbon dioxide seen in the Viking experiments was actually from the
disintegration of trace organic material.
These findings show that the road to indentifying
extraterrestrial life is long and arduous, with potential dead ends and
misinterpretations. But the payoff of a positive detection is so staggering,
the long haul and lively debate among scientists is well worth it.
A titanic battle of the giants is looming in intergalactic
space. The neighboring spiral galaxy in the constellation Andromeda is falling
toward us at a speed of one million miles per hour. At that velocity it will
plow into our Milky Way only a few billion years from now.
This close-to-home galaxy mergers ranks among the biggest
big bang-ups in the universe, and it's dramatically illustrated in
the Discovery Channel's upcoming TV series -- Cosmic Collisions.
Wait -- galaxies collide? At first glance this may sound counterintuitive; after all, Andromeda is more than a million times farther away than the nearest star to
our sun, so it seems there would be no chance of them ever colliding.
But consider that our Milky Way galaxy is 100,000 light
years across, and is separated from Andromeda by 22 galaxy diameters (2.2
million light years). By comparison, the sun is nearly a million miles across.
The nearest star, Proxima Centauri, is 100 million solar diameters away (24
trillion miles).
Put another way, if the sun were the size of a hockey puck,
the nearest star would be -- to scale -- 4,700 miles away! But if the Milky Way were the size of a hockey puck,
the Andromeda galaxy would be another hockey puck located a little less than
six feet away. That's within gravity's striking distance for a pair of galaxies
that each weigh a few trillion solar masses.
Supercomputer simulations that model the galaxies'
gravitational pull on each other give us a preview of the close encounter
that's coming (the actual collision will span one billion years). It looks sort
of like what happens in the children's poem the Gingham Dog and the Calico Cat, who
rip each other apart. The stars are scatted like a fallen box of marbles and
the galaxies lose their trademark spiral shape and finally morph into a giant
elliptical galaxy.
This is more than theory though. Over the past few decades
astronomers have collected dramatic snapshots of pairs of galaxies colliding,
or more politely put, interacting.
Sometimes more than two galaxies get into the act. One of
the most spectacular examples is the mosh pit called Stephan's quintet of five
galaxies mixing it up. Hubble Space Telescopes has shown that this was more the
case in the early universe because it was smaller, and galaxies bumped intro
each other more often.
When you view computer simulations, it looks like the end of
the line for anyone living in a colliding pair of galaxies. But this couldn't
be further from the truth.
Remember how comparatively far apart stars are? Even if another galaxy passed through the
Milky Way the sun would never collide with another star.
But what other bad things might happen to our solar system
in a galaxy collision? On closer
inspection it's sort of like the aftermath of a Roadrunner vs. Coyote cartoon. Despite all hell breaking
loose in the dynamics of the collision, the vast majority of earthlike planets
would go on with life as usual.
The biggest consequence of a galaxy collision is that stars
are tossed along gravitational tidal arms that stretch out each galaxy to
resemble an s-shaped fan blade. During the bang-up our solar system may find
itself rapidly relocated in one of these long arms. Our distant descendants
would have a truly bird's-eye view of the galaxy makeover in progress.
Billions of new stars would be born is a firestorm of
star birth triggered by the impact's compression of cold hydrogen in each
galaxy. Five billion years from now the sky will be ablaze with gem-like
clusters of brilliant hot blue stars and glowing nebulae. It will be a great
time to be an astronomer.
The downside of a having a beautiful faux Van Gogh Starry
Night sky is that there will be many more massive stars that explode as
supernovae and belch out lethal radiation. Mergers of double stars may cause
gamma ray bursts that would barbecue planets caught in their death-ray beam
within a few hundred light-years. But given the vastness of the galaxy this is not
as doomsday-ish as it sounds. The large majority of stars and planets will go
on unscathed.
Another scary consequence is that the 3 billion-solar-mass
black hole in the core of the Milky Way would merge with the 4 billion-solar-mass black hole in Andromeda. This would send gravitational waves rippling
across the galaxy that would monetarily pinch Earth's diameter by one-inch,
like squeezing a soccer ball.
Gas falling toward the monster black hole would be heated
and expelled along a blowtorch-like beam of high-speed particles and radiation
called an extragalactic jet. Any unlucky planet caught in the beam could see
much of its atmosphere stripped away.
However, a huge teardrop shaped solar wind “bubble” around
our sun could serve as a buffer to deflect the jet particles, depending on the
sun's distance and beam intensity. Also, a laser-narrow jet would only affect a
small fraction of the stars in the Milky Way.
Probably the biggest risk to Earth would come from having a
near-passing star gravitationally perturb the Oort cloud of comets. Like
shaking apples out of a tree, the dislodged comets would fall into the inner
solar system. A shower of wayward comets would bombard Earth, causing global
mass extinctions.
Now, to avoid any more melodrama, all of this could very well be a moot
point -- the sun is scheduled to burn out in 5 billion years, just when the
intergalactic fun is beginning.
The other unknown is that we won't know if the galaxy close-encounter
will be a head-on collision or glancing blow. Astronomers do not precisely know
if the Andromeda galaxy is on a trajectory causing it to swing wide of us. In
fact the Milky Way and Andromeda may simply orbit each other for quite some
time, like two Sumo wrestlers sizing each other up.
The bottom line is that the universe is indifferent to our
fate. Trillions of new planets could be born out of such a galactic close
encounter, even if it did mean demolishing old homesteaders like Earth.
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