Can Telescopes See The Flag On The Moon
Do you look at the Moon and often wonder if your telescope can see the flags that the astronauts planted when they landed there? On July 20, 1969, Apollo 11 astronauts Neil Armstrong and Buzz Aldrin took their first steps on the Moon and raised an American flag at the landing site. Every Apollo crew after them followed suit and planted a flag on each mission that landed on The Moon.
But, can you see those flags? Telescope on Earth can’t see the flags on the Moon’s surface, not even the Hubble Space Telescope can help you catch a glimpse of the flags as they are just too small for any telescope. The laws of optics come in to play here.
The flag on the moon is 4 feet (125cm) long and you would need an optical wavelength telescope of around 200 meters in diameter to see it.
The Hubble Telescope’s 2.4 metres mirror has a resolution of 0.024″ in ultraviolet light, which translates to 141 feet (43 meters) at the Moon’s distance. In visible light, the resolution becomes 0.05″, which is close to 300 feet, so a 4 feet flag would be much too small to be seen by the HST.
Armstrong and Aldrin reportedly found it a bit difficult to insert the flag pole into the Moon’s surface, and only managed to get it about seven inches deep. Moreover, the flag could not even stand on its own.
It was discovered later that the Moon dust has a different profile than the dust present on Earth. Dust on Earth has rounded edges whereas the Moon dust has sharp edges. The sharp edges of the Moon dust make them catch against each other, making it difficult to stick items into them.
Also, planting the flag on the Moon is very different from planting it on the Earth. With virtually no atmosphere on the moon—and, therefore, no wind—flags that fly freely on Earth would hang like limp cloth in the Moon’s environment. So American engineers had to come up with a different flagpole design.
On a flagpole meant for the Earth, the flag is attached at the hoist—the vertical section closest to the pole—at both the top and bottom of the flag. The pole might slide through a sleeve on the hoist side of the flag, or attach by grommets or some other type of fastener. A lunar flag, however, is anchored to the pole only at the bottom. A horizontal crossbar at the top mainly holds it in place.
Is the flag still on the Moon?
Yes, flags from all the six Apollo missions are still on the Moon. Images taken by NASA’s Lunar Reconnaissance Orbiter in 2012 do show that at least five out six flags still stand. However, unlike Earth, the moon lacks an atmosphere capable of blocking out the worst of the sun’s rays. It wouldn’t have taken long for the ultraviolet light to eat away at the dye and bleach the flags white.
The Apollo 11 flag that was left on the Moon is no longer standing. In fact, it’s been flat on the ground since the moment Aldrin and Neil Armstrong lifted off. As the Eagle module ignited its engines and rose, spewing exhaust around, the flag blew over and fell down.
For more than forty years, the flags have been exposed to the full fury of the Moon’s environment – alternating 14 days of searing sunlight and 100° C heat with 14 days of extreme cold temperature hovering around -150° C darkness. But even more damaging is the intense ultraviolet (UV) radiation from the pure unfiltered sunlight on the cloth (rayon) from which the Apollo flags were made.
Even on Earth, the colors of a cloth flag flown in bright sunlight for many years will eventually fade and need to be replaced. So it is likely that the American flags have been rendered blank, bleached white by the UV radiation of unfiltered sunlight on the Moon’s surface. Some of them may even have begun to physically disintegrate under the intense flux.
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How many flags are there on the Moon?
There are 7 flags on the moon, 6 of them are American. The US planted the first flag on the Moon during the manned Apollo 11 mission in 1969. Five further US flags were planted on the Moon’s surface during subsequent Apollo missions up until 1972.
On December 3, 2020, China became the second country to plant a flag on the Moon when the sample-collecting Chang’e 5 moon lander deployed a small version of China’s five-star red flag.
What countries have a flag on the moon?
The United States and China are the only two countries to have physically placed flags on the moon. Four other countries — China, Japan, India and the former Soviet Union — and the European Space Agency have sent unmanned spacecraft or probes to the moon.