Hubble Deep Space Image

"Scanning the heavens for the first time since the successful December 1999 servicing mission, NASA's Hubble Space Telescope imaged a giant, cosmic magnifying glass, a massive cluster of galaxies called Abell 2218. This 'hefty' cluster resides in the constellation Draco, some 2 billion light-years from Earth. The cluster is so massive that its enormous gravitational field deflects light rays passing through it, much as an optical lens bends light to form an image. This phenomenon, called gravitational lensing, magnifies, brightens, and distorts images from faraway objects. The cluster's magnifying powers provides a powerful "zoom lens" for viewing distant galaxies that could not normally be observed with the largest telescopes. The picture is dominated by spiral and elliptical galaxies. Resembling a string of tree lights, the biggest and brightest galaxies are members of the foreground cluster. Researchers are intrigued by a tiny red dot just left of top center. This dot may be an extremely remote object made visible by the cluster's magnifying powers. Further investigation is needed to confirm the object's identity. The color picture already reveals several arc-shaped features that are embedded in the cluster and cannot be easily seen in the black-and- white image. The colors in this picture yield clues to the ages, distances, and temperatures of stars, the stuff of galaxies. Blue pinpoints hot young stars. The yellow-white color of several of the galaxies represents the combined light of many stars. Red identifies cool stars, old stars, and the glow of stars in distant galaxies. This view is only possible by combining Hubble's unique image quality with the rare lensing effect provided by the magnifying cluster." NASA description.

自从1999年12月成功的维修任务以来，NASA的哈勃空间望远镜首次扫描天空，拍摄了一幅巨大的宇宙放大镜——一个名为Abell 2218的庞大星系团。这个“庞大”的星系团位于龙座，距离地球约20亿光年。由于其质量巨大，其巨大的引力场会弯曲通过它的光束，就像光学透镜弯曲光线形成图像一样。这种现象称为引力透镜效应，它放大、使远处物体的图像更明亮并扭曲图像。星系团的放大能力提供了一种强大的“变焦透镜”，使人们能够观察到那些通常无法用最大望远镜观测到的遥远星系。这张图片主要由螺旋星系和椭圆星系组成。这些最大的、最亮的星系是前景星系团的成员。研究人员对图片中左上方微小的红色点感到兴趣。这个点可能是一个极其遥远的天体，其存在是由于星系团的放大效应而显现的。需要进一步研究以确认该天体的身份。这张彩色图片已经揭示出几个嵌入在星系团中的弧形特征，这些特征在黑白图像中无法轻易看到。图片中的颜色提供了关于恒星的年龄、距离和温度的信息，这些是构成星系的物质。蓝色点代表炽热的年轻恒星。几个星系的黄白色代表许多恒星的光的总和。红色标识冷的恒星、古老的恒星以及遥远星系中的恒星光芒。这一视角只有通过将哈勃独特的图像质量与星系团提供的罕见透镜效应相结合才有可能实现。