What is a noctiluent?

1. What do you mean by noctilucent clouds?
2. What causes noctilucent clouds?
3. Are noctilucent clouds rare?
4. What are noctilucent clouds and where are they located?
5. When can you see noctilucent clouds UK?
6. Why are noctilucent clouds important?
7. How do you photograph noctilucent clouds?
8. How do you forecast noctilucent clouds?
9. How old is the oldest cloud on Earth?
10. How tall can cumulonimbus clouds get?
11. Where are cumulonimbus clouds found?
12. How much water can a cumulonimbus cloud hold?
13. Are noctilucent clouds a useful indicator of climate change in middle atmosphere?
14. How high is the Earth's atmosphere?
15. Where are nacreous clouds found?
16. Why is the sky glowing at night?
17. Why are wispy clouds found in the mesosphere?

What do you mean by noctilucent clouds?

Noctilucent clouds, or night shining clouds, are tenuous cloud-like phenomena in the upper atmosphere of Earth. They consist of ice crystals and are only visible during astronomical twilight. Noctilucent roughly means "night shining" in Latin.

What causes noctilucent clouds?

Noctilucent clouds form in the highest reaches of the atmosphere – the mesosphere – as much as 50 miles (80 km) above the Earth's surface. They're thought to be made of ice crystals that form on fine dust particles from meteors. ... Since atmospheric pressure decreases with altitude, the rising air expands.

Are noctilucent clouds rare?

Noctilucent clouds are extremely rare very high clouds seen in the night sky, usually on clear, summer nights. They become visible about the same time as the brightest stars and are usually bluish or silvery. Height of base: 200,000 feet.

What are noctilucent clouds and where are they located?

Noctilucent clouds are the highest clouds on Earth, and are located in the coldest part of planet Earth, the high-latitude summertime mesopause region (80–90 km). Composed of water-ice particles, they are nucleated by meteoric smoke particles.

When can you see noctilucent clouds UK?

They appear as thin streaks of “cloud”, often a pearly-blue colour, reminiscent of “mares-tail” cirrus cloud formations. NLCs can be seen from around mid May to early August during the darkest part of a summer's night when the Sun is between 6 – 16 degrees below the horizon.

Why are noctilucent clouds important?

Noctilucent clouds are of significant interest within the aeronomy and climate science communities as noctilucent clouds are very sensitive indicators for what is going on in the atmosphere at higher altitudes.

How do you photograph noctilucent clouds?

Noctilucent clouds evolve rather slowly and the twilight gives you enough light to adjust your settings depending on your camera's and lens's abilities. Once your gear is set up, use the manual setting to set focus at infinity on a bright source of light in the far background (a star or a streetlight).

How do you forecast noctilucent clouds?

Noctilucent clouds cannot be forecast, so if you want to observe them you will have to check the sky from time to time during every clear night. They occur typically around latitudes of 60^o north or south, so depending on your latitude you may have to look north, south or overhead.

How old is the oldest cloud on Earth?

Astronomers have discovered the largest and oldest mass of water ever detected in the universe — a gigantic, 12-billion-year-old cloud harboring 140 trillion times more water than all of Earth's oceans combined.

How tall can cumulonimbus clouds get?

Fueled by vigorous convective updrafts (sometimes in excess 50 knots), the tops of cumulonimbus clouds can easily reach 39,000 feet (12,000 meters) or higher.

Where are cumulonimbus clouds found?

Cumulonimbus clouds form in the lower part of the troposphere, the layer of the atmosphere closest to the surface of the Earth.

How much water can a cumulonimbus cloud hold?

A typical cumulus cloud carries about half-a-gram of water in each cubic metre — that's the weight of a big garden pea. A big fat dark cumulonimbus cloud could carry up to six times as much water (say, three grams of water per cubic metre).

Are noctilucent clouds a useful indicator of climate change in middle atmosphere?

The results suggest noctilucent clouds are a sign that human-caused climate change is affecting the middle atmosphere, according to the authors. Whether thicker, more visible noctilucent clouds could influence Earth's climate themselves is the subject of future research, Lübken said.

How high is the Earth's atmosphere?

Earth's atmosphere stretches from the surface of the planet up to as far as 10,000 kilometers (6,214 miles) above. After that, the atmosphere blends into space.

Where are nacreous clouds found?

Ice polar stratospheric clouds, or nacreous clouds, occur mainly at high latitudes during the winter when temperatures in the stratosphere fall below the frost point. They are most common in Antarctica, but have also been observed in the Arctic, Scotland, Scandinavia, Alaska, Canada and the northern Russian Federation.

Why is the sky glowing at night?

Electric lighting also increases night sky brightness and is the human-made source of sky glow. Light that is either emitted directly upward by luminaires or reflected from the ground is scattered by dust and gas molecules in the atmosphere, producing a luminous background.

Why are wispy clouds found in the mesosphere?

As the mesosphere contains very little moisture, approximately one hundred millionth that of air from the Sahara, and is extremely thin, the ice crystals can form only at temperatures below about −120 °C (−184 °F). ... Noctilucent clouds form mostly near the polar regions, because the mesosphere is coldest there.