Astronomy Picture of the Day

Explanation: Few cosmic vistas excite the imagination like the Orion Nebula, an immense stellar nursery some 1,500 light-years away. Spanning about 40 light-years across the region, this new infrared image from the Spitzer Space Telescope was constructed from data intended to monitor the brightness of the nebula's young stars, many still surrounded by dusty, planet-forming disks. Orion's young stars are only about 1 million years old, compared to the Sun's age of 4.6 billion years. The region's hottest stars are found in the Trapezium Cluster, the brightest cluster near picture centre. Spitzer's liquid helium coolant ran out in May 2009, so this false colour view is from two channels that still remain sensitive to infrared light at warmer operating temperatures.