This picture of Andromeda shows not only where stars are now, but where stars will soon be. Of course, the big, beautiful Andromeda Galaxy, M31, is a spiral galaxy -- and a mere 2.5 million light-years away. Both space-based and ground-based observatories have been here combined to produce this intriguing composite image of Andromeda, at wavelengths both inside and outside normally visible light. The visible light shows where M31's stars are now -- as highlighted in white and blue hues and imaged by the Hubble, Subaru, and Mayall telescopes. The infrared light shows where M31's future stars will soon form -- as highlighted in orange hues and imaged by NASA's Spitzer Space Telescope. The infrared light tracks enormous lanes of dust, warmed by stars, sweeping along Andromeda's spiral arms. This dust is a tracer of the galaxy's vast interstellar gas -- the raw material for future star formation. These new stars will likely form over the next hundred million years, surely well before Andromeda merges with our Milky Way Galaxy in about 5 billion years.?

這張仙女座的照片不僅顯示了恒星現(xiàn)在的位置，而且還顯示了恒星即將出現(xiàn)的位置。當(dāng)然，美麗的仙女座大星系M31是一個(gè)螺旋星系，距離我們只有250萬(wàn)光年。在這里，天基和地基觀測(cè)站結(jié)合在一起，在正?？梢姽鈨?nèi)外的波長(zhǎng)上生成了這幅有趣的仙女座綜合圖像?？梢姽怙@示了M31恒星現(xiàn)在的位置，如哈勃、斯巴魯和梅亞爾望遠(yuǎn)鏡所拍攝的白色和藍(lán)色高亮顯示。紅外光顯示了M31未來(lái)恒星即將形成的位置，如NASA斯皮策太空望遠(yuǎn)鏡拍攝到的橙色高亮顯示。紅外光沿著仙女座的旋臂，追蹤著被恒星加熱的巨大塵埃帶。這些塵埃是銀河系巨大星際氣體的示蹤劑，星際氣體是未來(lái)恒星形成的原材料。這些新恒星很可能會(huì)在未來(lái)一億年內(nèi)形成，肯定會(huì)在大約50億年后仙女座星系與銀河系合并之前形成。