THE SUN
The Sun is now in the quietest phase of its 11-year activity cycle, the solar minimum - in fact, it has been unusually quiet this year - with over 200 days so far with no observed sunspots. The solar wind has also dropped to its lowest levels in 50 years. Scientists are unsure of the significance of this unusual calm, but are continually monitoring our closest star with an array of telescopes and satellites. Seen below are some recent images of the Sun in more active times.
A sweeping prominence, a huge cloud of relatively cool dense plasma is seen suspended in the Sun's hot, thin corona. At times, promineces can erupt, escaping the Sun's atmosphere. Emission in this spectral line shows the upper chromosphere at a temperature of about 60,000 degrees K (over 100,000 degrees F). Every feature in the image traces magnetic field structure. The hottest areas appear almost white, while the darker red areas indicate cooler temperatures.
The Sun is now in the quietest phase of its 11-year activity cycle, the solar minimum - in fact, it has been unusually quiet this year - with over 200 days so far with no observed sunspots. The solar wind has also dropped to its lowest levels in 50 years. Scientists are unsure of the significance of this unusual calm, but are continually monitoring our closest star with an array of telescopes and satellites. Seen below are some recent images of the Sun in more active times.
A sweeping prominence, a huge cloud of relatively cool dense plasma is seen suspended in the Sun's hot, thin corona. At times, promineces can erupt, escaping the Sun's atmosphere. Emission in this spectral line shows the upper chromosphere at a temperature of about 60,000 degrees K (over 100,000 degrees F). Every feature in the image traces magnetic field structure. The hottest areas appear almost white, while the darker red areas indicate cooler temperatures.
NASA's STEREO satellite captured the first images ever of a collision between a solar "hurricane", called a coronal mass ejection (CME), and a comet on April 4, 2007. The collision caused the complete detachment of the comet's plasma tail. Comets are icy leftovers from the solar system's formation billions of years ago. They usually hang out in the cold, distant regions of the solar system, but occasionally a gravitational tug from a planet, another comet, or even a nearby star sends them into the inner solar system. Once there, the sun's heat and radiation vaporizes gas and dust from the comet, forming its tail. Comets typically have two tails, one made of dust and a fainter one made of electrically conducting gas, called plasma.
The planet Venus is seen by NASA's TRACE satellite, at the start of its transit across the sun on June 8, 2004.
Hinode (formerly known as Solar-B) successfully captured a massive solar flare on 13 December 2006. It was one of the largest flares occurring in that period of solar activity minimum
On November 8, 2006, Mercury is seen, beginning a transit in front of the Sun.
his TRACE 171Å-wavelength image from November 11, 2006 shows a sizeable active region at the east limb of the Sun (rotated clockwise 90 degrees so north is to the right) just as it rotates onto Earth-facing hemisphere. Notice the low-lying dark structures of filaments at the leading edge of the region, some "levitating"
his TRACE 171Å-wavelength image from November 11, 2006 shows a sizeable active region at the east limb of the Sun (rotated clockwise 90 degrees so north is to the right) just as it rotates onto Earth-facing hemisphere. Notice the low-lying dark structures of filaments at the leading edge of the region, some "levitating"
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