by Kim Malville
Jupiter, in the constellation of Taurus, dominates the evening skies. Later in the month Saturn will be easily visible, moving retrograde toward Spica.
April 12-14: Watch the crescent moon move through the sky, past the Pleiades, Aldebaran, and finally Jupiter
April 22: Lyrid Meteor Shower: This collection of meteors coming out of the sky near Vega is pretty unpredictable. In 1982 there were 90 per hour; last year there were 25, and some years only 10 per hour. In 687 BC, Chinese reported meteors dropping out of the sky like rain. The best time this year will be just before dawn on April 22, after the moon has set and the sky is still dark.
April 24: Spica is close to the nearly full moon.
April 25: Full moon. Saturn lies to the upper left of the moon.
April 27-28: Saturn is in opposition to the sun, moving rapidly retrograde, rising at dusk, and setting at dawn.
Aliens amongst us ?
The tiny Tardigrade is the best candidate for a visitor from space. Tardigrades are able to live for decades without food or water, to survive temperatures from near absolute zero to well above the boiling point of water, to survive pressures from near zero to well above that on ocean floors, and to survive direct exposure to dangerous radiations. In September 2007, tardigrades were taken into low Earth orbit and for 10 days were exposed to the vacuum of space. After being rehydrated back on Earth, over 68% of the subjects protected from high-energy UV radiation survived and many of these produced viable embryos. In May 2011, Italian scientists sent tardigrades into space along with other extremophiles on STS-134, the final flight of Space Shuttle Endeavour. Their conclusion was that microgravity and cosmic radiation did not significantly affect survival of tardigrades, confirming that tardigrades represent a useful animal for space research, whatever that means.
In probably one of the dumbest space missions imaginable, some of these miniature water-bears almost became extraterrestrials recently when they were launched toward to the Martian moon Phobos on board the Russian mission Fobos-Grunt. Fortunately, the launch failed. If it had succeeded when folks visit Mars in the future and discover these creatures, they wouldn’t know if they were terrestrial contamination or indigenous. These hardy creatures could survive beneath the soils of Mars for some time.
Since tardigrades can survive being heated for only a few minutes to 304°F, Venus would be too hot. They couldn’t survive in the 900°F surface temperature of that planet. They could, however, survive a voyage through interplanetary space, because some survived chilled for days at -328° F. They could be hanging out in stony meteorites or even asteroids. Water bears can withstand pressures of 6,000 atmospheres, which is nearly six times the pressure of water in the Mariana trench. Some could be floating in the dense atmospheres of Jupiter and other gas giants.
The oldest light in the universe
On March 21, the results of 15 months of measurements by the Plank Space Telescope of the European Space Agency were released. Their primary result was the most precise measurement yet of the radiation from the Big Bang (otherwise known as the Fireball of Creation). To appreciate fully the picture of the ancient light of the universe taken by the Planck space telescope, imagine wrapping it entirely around yourself. We are inside it. Like those sometimes embarrassing pictures in a dusty family photo album, this is a snapshot of the baby universe when it was much smaller, only 380,000 years old, and not very cute.
Since the time picture was taken, the universe has continued to expand and the irregularities in the figure have grown into all the cockroaches, whales, planets, stars, and galaxies that we see around us. The universe is now some 40 billion light years across. However, because light can travel only at a finite speed, we can see only to a distance of 13.8 billion light years. Beyond that horizon there is an immense unknowable universe, invisible and totally unreachable. Because light only gives us pictures of the universe that was, we and future generations shall never know the fullness the space in which we live. Note that the fluctuations are not uniformly distributed across the sky. There is a large cold spot in the southern part of the sky. One fascinating and luscious possibility is that this unexpected irregularity may be the remnant of the earlier universe out of which ours was born.
The new measurements from the Planck space telescope should give the immodest ones among us reason to pause. Not only are we humans small in stature, but also the matter out of which we, the earth, our sun and all the stars and galaxies are formed makes up only 4.9% of the total mass-energy of the universe. Dark matter, which has thus far only been detected indirectly by ability to hold galaxies together through its gravitational influence, makes up 26.8%, What it is exactly remains a mystery. Dark energy, equally mysterious and inscrutable, is the force that pushes galaxies apart, causing the accelerating expansion of the universe. For better or worse, it accounts for the majority of the stuff of the universe. Considering how long humans have pondered the mysteries of the universe, it is stunning how little we know!
For the last two weeks of March we were treated to views of the new comet PanSTAARS, which appeared in the western sky soon after sunset. It reached its brightest about March 20, and then it began to fade. This photograph was taken on March 15 with a powerful telephoto lens from Stuttgart at a distance of 80 km.