Looking Up by Bob Eklund

Sun Fire, Moon Ice, Westchester Stars

An international team of solar and space scientists have built the most complete picture yet of the full impact of large solar eruptions called Coronal Mass Ejections (CMEs) as these huge bodies of solar material travel from the Sun to the Earth. Dr. Mario Bisi of Aberystwyth University (in Wales) presented the study’s results at the British Royal Astronomical Society’s meeting April 13 in Glasgow.

CMEs—giant eruptions of the Sun’s atmosphere from its “surface” which are ejected out into space—are many times larger than the Earth and typically contain over a billion tons of matter. They travel away from the Sun at speeds of up to several million miles per hour and can impact into comets, asteroids, and planets—including the Earth.

Our planet is normally protected from CMEs by our own magnetic field, but the twisted magnetic fields carried by CMEs can break through this protective shield, causing particles to stream down over the Earth’s polar regions. They typically lead to displays of the northern and southern lights (aurora borealis and australis). But CMEs can also have less appealing consequences such as power outages on the ground, interference with communications, and damage to Earth-orbiting satellites. They can also present a health risk to astronauts who happen to be conducting a space walk at the time a CME event interacts with the Earth.

NEW STUDY SHOWS THICK ICE ON THE MOON

Water ice exists in large quantities in many small craters near the Moon’s north pole, according to analysis of initial results from the miniature synthetic aperture radar (Mini-SAR) experiment on board the Indian Chandrayaan 1 spacecraft, which mapped most of the area near the north pole of the Moon between February and April 2009. The Mini-SAR instrument collected data on the polarization of radio waves reflected off the lunar surface. These data give the researchers insight into lunar surface features. For instance, high values of the circular polarization ratio (CPR) indicate either surface roughness or ice.

The observations suggest that water ice exists in many of the small craters in permanent darkness near the north pole of the Moon. According to the scientists’ analysis, the CPR values recorded indicate that this ice must be at least 6.5–9.8 feet thick. The researchers note that the ice is not distributed evenly over the lunar surface, suggesting that it may have been deposited through an episodic deposition process such as comet or asteroid impacts. Because these lunar craters near the north pole are in permanent shadow, ice would remain stable there indefinitely.

COMMUNITY TELESCOPES POINT STARWARD APRIL 24

The community is invited to share a family evening under the stars on Saturday, April 24, with author/astronomy educator Bob Eklund and fellow volunteers from local astronomy clubs. This free event is 7:30–10:00 p.m. in the parking lot of the Christian Science Church, 7855 Alverstone Ave., corner of 79th St., Westchester. (The backup date in case the event is clouded out is a month later, Saturday, May 22.)

Everyone is invited to look through high-quality telescopes at the planet Saturn, the craters of the Moon, and stars and nebulae. The April 24 celebration of the sky is on Astronomy Day and is one of many events scheduled by the international astronomy advocacy organization Astronomers Without Borders during April—designated Global Astronomy Month (GAM). For a complete schedule of GAM events, see www.astronomerswithoutborders.org.

People of all ages—and especially children—are encouraged to come learn about the sky from knowledgeable astronomers, and anyone who has a telescope of his or her own is welcome to bring it. For more star party information, call (310) 216-5947.

You can contact Bob Eklund at: email [email protected], website www.bobeklund.com

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