all Sallie Baliunas stories

Solar evidence points to human causes of climate change

404132862 — Sat, 16 Feb 2008 18:24:15 -0500

It’s getting harder and harder to blame the sun for causing the gradual increase in global temperatures that are now being seen in the climate record, scientists said today.

In a symposium today on the potential role of solar variability — increases in heat coming from the sun — held in Boston at the annual meeting of the American Association for the Advancement of Science, experts in solar science, climate modeling, and atmospheric science explored the issues surrounding who or what is to blame for the rapid rate of change.

Asteroid Juno has a bite out of it

70652986 — Mon, 26 Mar 2007 05:31:23 -0400

Juno, the third asteroid ever discovered, was first spotted by astronomers early in the 19th century. It orbits the Sun with thousands of other bits of space rock in the main asteroid belt between Mars and Jupiter. One of the largest asteroids, at a size of 150 miles across, Juno essentially is a leftover building block of the solar system. Astronomer Sallie Baliunas of the Harvard-Smithsonian Center for Astrophysics and colleagues photographed Juno when it was located relatively nearby in astronomical terms, about 10 percent further from the Earth than the Earth is from the Sun. Even at that distance, Juno appeared very tiny in the sky. Imaging Juno at the high resolution needed to resolve surface details thus presented a challenge. To solve the problem, the scientists used an adaptive optics system connected to the 100-inch Hooker telescope at Mount Wilson Observatory. Their surface maps showed that Juno, like other asteroids, is misshapen rather than round, and that it has "sharp" edges. Even better, as Juno tumbled through space during the night of observing, a "bite" came into view - an area that appeared dark as seen at near-infrared wavelengths.

Global warming is not so hot

70652986 — Mon, 26 Mar 2007 05:29:36 -0400

Scientists at the Harvard-Smithsonian Center for Astrophysics took a look at how weather has changed in the past 1,000 years. They looked at studies of changes in glaciers, corals, stalagmites, and fossils. They checked investigations of cores drilled out of ice caps and sediments lying on the bottom of lakes, rivers, and seas. They examined research on pollen, tree rings, tree lines, and junk left over from old cultures and colonies. Their conclusion: We are not living either in the warmest years of the past millennium nor in a time with the most extreme weather. This review of changes in nature and culture during the past 1,000 years was published in the April 11, 2003 issue of the Journal of Energy and Environment. It puts subjective observations of climate change on a much firmer objective foundation. For example, tree-ring data show that temperatures were warmer than now in many far northern regions from 950 to 1100 A.D. From 800 to 1300 A.D., the Medieval Warm Period, many parts of the world were warmer than they have been in recent decades. But temperatures now (including last winter) are generally much milder than they were from 1300 to 1900, the Little Ice Age.