Star Talk: Summer Triangle greets sky watchers

Summer started last weekend and the constellations of the new season are readily visible in the even

Summer started last weekend and the constellations of the new season are readily visible in the evening sky.

Looking east about 10 p.m., we can see three bright stars outlining a giant star pattern known as the Summer Triangle. Its brightest star, Vega, is already more than halfway up the eastern sky by midevening. Vega is a brilliant star that shines with an intense bluish-white light and glistens as the marker star of the constellation Lyra the lyre. Lyra is the mythical harp of Orpheus that was fabled to calm the beast.

Moving northeast from Vega leads to Deneb, a star that is not quite as bright as Vega. Deneb is the second star of the Summer Triangle and represents the tail of Cygnus the swan. A line of stars runs south from Deneb that outlines the swan’s body and long neck. This stellar lineup ends at the swan’s beak with a star called Alberio. Found near the middle of the Summer Triangle, Alberio is a double star. A telescope will easily show this pair of stars with their contrasting colors. Nearer to Deneb is a crossbeam of stars that displays the swan’s outstretched wings.

The next star is Altair. During summer evenings, it is the closest of the three triangle stars to the horizon. Altair belongs to the constellation of Aquila the eagle and denotes the bird’s beak, while fainter stars represent its open wings. Look for Altair low in the eastern sky after 10 p.m.

Phoenix update

On May 25, the Phoenix Mars Lander successfully set down on the arctic planes of the Red Planet. After it extended its solar panels to generate power, one of the first instruments the lander activated was its weather station. During its first day on Mars, Phoenix measured the air temperature and found that it ranged from an afternoon high of minus 20 degrees Fahrenheit to an early morning low of minus 115 degrees.

During its first week on the planet, the lander’s titanium scoop was used to dig several shallow trenches in the frozen Martian soil. Its first “excavation” revealed bright regions in the soil that could be ice. In fact, camera surveys around Phoenix show that its three landing legs appear to be resting on a slab of ice. It is believed that the spacecraft’s landing thrusters cleared this topsoil away on approach to the surface.

During its nominal three-month operating period, the Phoenix lander will continue to dig into the Martian permafrost layer. Experiments on-board Phoenix will be checking for evidence of past water and organic material to determine whether the far northern latitudes of Mars could have supported primitive life in the distant past.

Hubble delay

NASA has postponed the liftoff date for the final Hubble Space Telescope repair mission. Launch day was moved from the end of August to the first week in October. A delay in the delivery of components, particularly with the external fuel tanks for Endeavor, the backup shuttle for this mission, was cited as the reason.

Although the Atlantis shuttle will fly the repair mission, designated STS-125, Endeavor is required to be ready to fly a rescue mission, if needed. Since Atlantis will be in Hubble’s orbit around Earth, in the event of an emergency, Atlantis would not be able to reach the Space Station. NASA officials only approved this last flight to Hubble if there was a backup shuttle ready to launch within two weeks after Atlantis lifts off — the first time this has been done for any space mission.

In addition, NASA has decided that this trip will not be the last flight for the Atlantis space shuttle. The plan now is to assign Atlantis two additional flights after its trip to Hubble. Endeavor will fly STS-126, the next mission to the Space Station, currently scheduled for November.

GLAST off

On June 11 at 12:05 p.m., NASA launched the Gamma-ray Large Area Space Telescope or GLAST spacecraft. Once it reached its proper orbit 350 miles above Earth, it deployed its solar panels and is currently being prepared to observe gamma rays — the most energetic form of light — from many celestial sources.

This makes GLAST an important space observatory because it can “see” extreme, high-energy regions of the cosmos that might otherwise be invisible. Such space environments include supermassive black holes, merging neutron stars, and mysterious gamma ray bursters — phenomena that blast gamma rays from deep space for a few seconds while outshining all other gamma ray sources across the entire universe!

GLAST will be powerful tool for studying black holes. Near certain black holes, gases of the interstellar medium violently spiral around the hole only to be blasted outward at speeds approaching that of light, a process that generates gamma rays.

In high-energy phenomena such as these celestial jets, atomic and nuclear particles are accelerated to speeds far greater than those that could be achieved by any atom smasher on Earth. Such enormous velocities allow physicists to study how elementary particles interact at these enormous energies.

July sky

Mars, Saturn and the star Regulus appear very close together during July but very low in the western sky. Look for this trio as soon as the sky gets dark in that direction — a little more than an hour after sunset. The crescent moon will be with the three on the evening of July 6, and the two planets will appear closest on July 10.

Jupiter is above the southeastern horizon by nightfall. Seen just east of the central teapot form of Sagittarius, Jupiter is outshining all the stars of the summer night sky. Watch for the nearly full moon close to Jupiter during the nights of July 16 and 17.

Categories: Life and Arts

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