七彩万花筒

紫外线太阳床太阳光中的紫外线,杀菌和消毒能力都很强,有助于人体健康。可在挪威、丹麦、瑞典以及英格兰、苏格兰和北爱尔兰等地方,有的每年有一     

七彩万花筒

正炸弹树非洲的北部地区,生长着一种名副其实的炸弹树。它的果实有柚子那样大,果皮外壳呈金黄色,非常坚硬。到成熟时,果实会突然爆开,爆炸的威力像小型手榴弹一样,外壳碎片能飞出20多米远。因此,在果实爆炸后,人们往往能在树的周围捡到被炸伤的鸟。(文/姚畅)     

Coronal structure and brightness profile of the total solar eclipse on August 1, 2008

Solar corona is the outermost part of the solar atmosphere. Coronal activities influence space environment between the Sun and the Earth, space weather and the Earth itself. The total solar eclipse （TSE） is the best opportunity to observe the solar corona on ground. During the TSE 2008, a series of images of the corona and partial eclipse of solar disk were obtained using telescope and CCD camera. After image processing, preliminary results of coronal structure are given, and radial brightness profiles of the corona in directions of pole and equator of the Sun are measured. Though in solar activity minimum, the shape and structure of the corona are not symmetry. The equatorial regions are more extent than the polar one, and there are also larger differences between the east and west equatorial regions and between the south and north polar regions. Coronal streamers on east side of the equator, particularly the largest one in east-south direction, are very obvious. The coronal plume in south polar region consists of more polar rays than that in north polar region. These structures are also shown in other observations and data of SOHO. The radial brightness profiles in directions of pole and equator are similar to those of the Van de Hulst model in solar minimum, but there are a few differences due to coronal activity, which is shown in the isophote map of the corona.     

甲烷威胁地球

据国外有关报道,科学家们首次发现,北极地区海床底部数百万吨的甲烷正缓慢地释放到大气中,要知道甲烷这种气体蕴藏的能量是二氧化碳所含能量的20倍,它的大量涌入大气将给地球安全带来严重威胁。他们指出这是由于北极地区的气候日渐暖化,其永久性冻结地带逐渐融化,导致沉积在海底的大量甲烷慢慢浮出水面,该媒体已经对科学家们的初步发现做了详细报道。