Olgui/science

Mercury Transit the Sun on November 8
(Live webcast)


From the page: On November 8, 2006, Mercury will slowly slide across the face of the sun during an event known as a transit. A transit of Mercury is relatively rare--there are only about a dozen in a century.

The Exploratorium's Live@ crew will be at the Kitt Peak National Observatory, and, with the Kitt Peak staff, will Webcast the transit: a live five-hour telescope-only feed beginning at 11:00 am PST.

The transit will take place from 11:12 a.m. PST until 4:10 p.m. PST and will be visible from the Pacific, the Americas, eastern Asia, Australia, and New Zealand, although some locations will not be able to see the entire transit. Because of Mercury's diminutive size, the transit cannot be seen with the unaided eye, but it can be viewed with a telescope (with the proper filter) or with a homemade optical projector

Image © Exploratorium, The museum of science, art and human perception
(Palace of Fine Arts, San Francisco)

Viral fossil resurrected
From the page: In a controversial study, researchers have resurrected a retrovirus that infected our ancestors millions of years ago and now sits frozen in the human genome. Published online by Genome Research this week, the study may shed new light on the history of these genomic intruders, as well as their role in tumors. Although this particular virus, dubbed Phoenix, is a wimpy one, some argue that resuscitating any ancient virus is inherently risky and that the study should have undergone stricter reviews.

Retroviruses have the ability to make DNA copies of their RNA genomes and incorporate these into the host's genome. If this happens in a germ cell, the copy can be passed on to future generations. Indeed, the human genome is littered with the remnants of such human endogenous retroviruses (HERVs). So far, researchers had been unable to recover a complete, functional HERV from a human genome however; part of the reason, they assumed, was that mutations accumulated over the millennia had rendered such viruses dysfunctional.

image: Electron microscopy pictures show how the Phoenix virus, when infecting human cells, forms particles at the cell membrane.

Credit: Dewannieux et al., Genome Research