12 hours ago
The intriguing phenomena we can see in the skies this week
The summer evenings offer us the opportunity to sight some rather intriguing and beguiling phenomena.
Noctilucent clouds, (NLCs), make for an interesting spectacle after sunset, observable with the naked eye and quite eerie in appearance.
Around two hours after the Sun has set and looking above the northwest horizon, watch for wispy threads of cloud with a distinct blue and silver tinge to them.
Taken from the Latin for 'night-shining', NLCs are formed by sunlight reflecting off high-altitude ice crystals that are positioned right on the edge of space.
The time period after sunset is crucial if we are to catch NLCs, as around 90 minutes to two hours after the Sun has dipped below the horizon is when the necessary angle occurs for sunlight to catch the crystals and illuminate that part of the sky with this enchanting effect.
The beautiful and captivating sight sees the highest clouds in our atmosphere, about 50 miles above the Earth's surface, seem to glow and shimmer with this mesmerizing blue or silvery guise. In the summertime the mesosphere, (the third layer of the Earth's atmosphere where meteorites burn up), becomes cold enough to allow ice to form on suspended dust particles that are floating around in the clouds.
These particles may originate from meteorites falling from space, but equally so from other sources, possible volcanic, with the recent Mount Etna eruption billowing tons of debris into the atmosphere.
In fact, the first NLCs observations were recorded in 1885, two years after the eruption of Krakatoa, which may or may not have something to do with their appearance. Eruptions aside, rockets that have blasted off from Earth leave particle emissions from their exhaust systems, all contributing to the array of debris circulating in our atmosphere.
NLC's have been given a different name when seen from space looking back on Earth; polar mesospheric clouds, or (PMCs). However, the Earth is not the only place NLC's have been witnessed.
Launched in June 2003, Mars Express was not only the first European mission to Mars, but the first planetary mission operated entirely by Europe. There were reports of NLC's made three years into the Mars Express mission in 2006, with NASA's Curiosity Mars rover confirming the presence of NLC's in 2019.
Readers may well recall all the media hype over Asteroid 2024 YR4, which earlier this year was once considered the highest impact risk to Earth ever recorded. Earlier this week, NASA announced that previously collected data on the asteroid that has been reanalysed now reveals that the 174 to 220 feet-long chunk of rock is more likely to hit the Moon in 2032.
During the week ahead, watch for Mars in the evening sky as it moves its way slowly night by night, left to right, above the bright star Regulus in the constellation of Leo, the Lion, situated above the western horizon.
The International Space Station continues its early summer break and cannot be seen across our region at present.
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