ISSN:0031-9228    

DOI:10.1063/1.2409349

出版商:AIP    

年代:1902

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1510264

出版商:AIP    

年代:1902

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1510265

出版商:AIP    

年代:1902

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1510268

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

Modern Mars is cold, desolate, and dry. Its atmosphere contains a mere 0.03&percent; of water vapor. Water can't survive as a liquid. Only at the planet's poles do the temperature and pressure let water exist, as ice, on the surface.

ISSN:0031-9228    

DOI:10.1063/1.1510269

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

Sitting in the high Andean desert of northern Chile at an altitude of 5100 meters, the Cosmic Background Imager (CBI) has been scrutinizing the random microkelvin anisotropies of the cosmic microwave background (CMB) since the beginning of 2000. CBI is an interferometric microwave telescope operated by a collaboration of institutions in the US, Canada, and Chile, headed by Anthony Readhead and Stephen Padin at Caltech. The collaboration has now reported the results of its first full year of observing.

ISSN:0031-9228    

DOI:10.1063/1.1510270

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

Excitable media can be coaxed into complex spatiotemporal patterns, including spiral waves and oscillating tiger stripes (see PHYSICSTODAY, July 2001, page 18). Like the antics of the Three Stooges, this captivating behavior often emerges in a state of near or actual chaos. But the excitable medium on display here has been so thoroughly tamed that its handlers, a team from West Virginia University in Morgantown, not only keep the onset of chaos at bay, they also direct the patterning at will and bestow on individual waves the kinetic behavior of a particle under the influence of a potential.

ISSN:0031-9228    

DOI:10.1063/1.1510271

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

Just before President Bush delivered his bill to Congress on 18 June to establish the $37.5 billion Department of Homeland Security (DHS), the White House released analytical documents indicating what role science and technology would play in the department's war against terrorism. “America's vast science and technology base provides us with a key advantage,” one administration document said. “The department would press this advantage with a national research and development enterprise for homeland security comparable in emphasis and scope to that which has supported the national security community for more than fifty years.”

ISSN:0031-9228    

DOI:10.1063/1.1510272

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

The original red arming plug and green safety plug that were built for Little Boy, the first of only two atomic bombs ever used in combat, have been sold at auction for $167 000. The purchaser was Clay Perkins, a retired physicist in Rancho Santa Fe, California. The sale went ahead despite a last‐minute attempt by the US Air Force to block it for national security reasons.

ISSN:0031-9228    

DOI:10.1063/1.2409350

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

When David Southwood, the European Space Agency's director of science, emerged in May from several months of feverish strategizing, he delivered some surprisingly good news: ESA will fly all of its planned space exploration missions despite the recent blow to its science budget.

ISSN:0031-9228    

DOI:10.1063/1.1510273

出版商:AIP    

年代:1902

数据来源: AIP