Descopera cosmosul! In fiecare zi este prezentata o noua imagine sau fotografie a universului nostru fascinant, insotita de o explicatie scurta din partea unui astronom profesionist.
2003 December 30
Explicatie: (Edit) What caused the streaks in this Martian crater? Since the above image shows streaks occurring both inside and outside the crater, they were surely created after the crater-causing impact. Newly formed trails like these presented researchers with a tantalizing martian mystery but have now been identified as likely the work of miniature wind vortices known to occur on the red planet - martian dust devils. Another example of wind processes on an active Mars, dust devils had been detected passing near the Viking and Mars Pathfinder landers. Such spinning columns of rising air heated by the warm surface are common in dry and desert areas on planet Earth. Typically lasting only a few minutes, they becoming visible as they pick up loose dust. On Mars, dust devils can be up to 8 kilometers high and leave dark trails as they disturb the bright, reflective surface dust.
Autori & editori:
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
Un serviciu al: LHEA at NASA / GSFC
& Michigan Tech. U.