Question: If it is a full moon in Australia, is it also a full moon on the other side of the world?
Answer: The phases of the Moon are the same all around the world. Any two places that can see the Moon at the same time will see the same phase.
Each Moon phase happens at a precise point in the Moon's orbit around the Earth, and hence at a precise moment in time. This is the same moment all over the world, but will be a different local time for every time zone in the world.
For example, the first full moon of the 21st century occurred at 8:24pm on 9 January 2001, Universal Time. In Melbourne this moment was 7:24am on 10 January 2001, Australian Eastern Summer Time.
Of course opposite sides of the world will not be able to see the Moon at the same time. Only one half of the world will be able to see the moon when it is precisely at one of the phases. For the example I gave above, that Full Moon was visible from the United Kingdom, but not from Australia. The Moon had set in the west around two hours before it became full. However since the appearance of the Moon’s phase does not change very quickly, the Moon would have looked very full when it set.
Both places will see the moon the same. Whatever the phase of the moon (that is, how much of the moon’s sunlit side is visible from Earth - crescent, quarter, half, full, etc..), every place on Earth will see it the same in the 24 hours it takes Earth to spin (rotate) once on its axis. The moon takes a month to orbit the Earth so in 24 hours it won’t have travelled enough to make any obvious change to its phase. The only difference to how the moon can look will be which hemisphere you view from. The moon phase won’t change but the moon (and star patterns too) will turn upside down (invert) if you travel far enough north or south of the equator which is simple geometry or change of viewing angle.
Hi Jennifer - we checked with one of our Astronomy specialists at the Planetarium, and they've answered as follows:
Alaska is in the high latitudes in the northern hemisphere. For part of the year in winter the Sun will be below the horizon for several weeks and won’t rise each day. This is due to the tilt of the Earth’s axis which is 23.5 degrees from vertical. Six months later in summer Alaska will have the Sun above the horizon for a similar amount of time. The further you are away from the equator, and so closer to either the north or south pole, the more extreme this winter versus summer pattern is. This summer/winter pattern is opposite for high latitudes in the southern hemisphere.
The Moon is very different thing. It takes a month to travel around (orbit) the Earth and can appear in the night or day. Apart from the Sun, it’s the only thing in space we can see during the day because it’s so close. In the 24 hours it takes the Earth to turn once (rotate) on its axis the Moon will eventually be seen from every place on Earth.
Fiji lies 18 degrees south and on 2 November 2008 the moon was showing 14-15% of its illuminated surface (that is; a crescent phase looking like a capital “C” with horns or pointed ends). It rose around 6.30am in the East (ESE) and set about 8pm in the west (ESW). The key thing to know is when the photo was taken as during the day the moon’s orientation will slowly change as the Earth rotates and it appears to travel across the sky. The crescent moon will appear to turn or rotate clockwise, but here are some sample times and orientations to help pin it down… 7am moon like a “C” leaning to right with horns pointing to lower right. 10am moon “C” turned fully sideways (lying horizontal) with horns pointing directly down. 1pm moon “C” turned further (like mirror image or reversed C) with horns pointing to right. 4pm moon “C” turned more with horns pointing to upper left. 7pm moon “C” turned (lying on its back) with horns pointing directly upwards. I hope this makes it possible to orient the photo as close to the correct time it was taken.
Hi Shyla, when you see the moon during the day, the other side of the world which is having night would not see the moon at that moment. And conversely, when you see the moon at night, the other side of the earth having daytime would not see it at that moment. It may help to picture the earth rotating once every 24hrs and realise that is faster than the moon’s slower orbit around the earth, or, to put it the other way, the moon moves only a short distance in its orbit around the earth in the time earth completes a full spin.
Hi Pawan, good question! We often get the reverse; how much of the Moon can we see from Earth?
Yes, the Moon always has one side facing us because it turns once on its axis in the month it takes to orbit the Earth. It’s said to be “tidally locked” to Earth. But the Earth turns on its axis too but much faster - once every 24 hours - so on the Earth-facing side of the Moon you would see most of the Earth over that 24 hour period. However, for part of that time some of the Earth will be dark in night time so you would need a few days to see all the countries, continents and oceans in daylight. Also, the Moon’s orbit is at a small angle to Earth’s equator so it would take a while to see all of the Earth’s polar regions.
The phases of the Moon are the same no matter where you are on the Earth at the same time. If the Sun is positioned on the other side of the Earth then it would be night time at your viewing location, and the Moon would still be in its current phase. As the Earth revolves on its axis, we go from day to night, however the Moon, although it does revolve about the Earth, does not move a lot in relation to the Sun, so the phase stays the same no matter where you observe from.
If you're on the Moon looking at the Earth, then at some part of the day you would be able to see on one side of the Earth Okinawa and on the other side Minot, North Dakota. Conversely at the same time you would be able to see the Moon from both of these places.
If you look at the following website you can calculate the rise and set times of the Moon at any location around the world.: Geoscience Australia - Compute Moonrise & Moonset Times
Okinawa is at latitude 26.5 degrees North and longitude 128 degrees East, and Minot is 48.13 North and 101.7 West, so using the table you can see that on the 10th of January this year the Moon will rise at 21:20 UT (06:20 local time) in Okinawa while at Minot it will rise at 13:15 (7:15 local time) and set at 22:23. This means that on this date both locations will be able to see the moon for an hour.
Hi Chris - We think the Moon infosheet may help explain this a bit better; if you look at the diagrams on this page showing the phases of the moon, they depict the view from the southern hemisphere. From the northern hemisphere then these are the other way around because we are effectively “upside down”. At first quarter, as you can see the Moon rises about midday so the Sun would be shining on its left side.
Hope this of some help
The Moon phases are the same the whole world over. The time the Moon rises and sets however vary depending on your location. The Geoscience Australia website has a tool you can use to help you calculate rise and set times.
A new Moon cannot be seen, but will be just visible as a crescent morning the day after very low down in the morning sky. You might also want to have a look at the Museum's Moon infosheet for further information.
There was a New Moon on Monday 23rd so no Moon could be seen for a couple of days either side of that. Check out Skynotes for this information. http://museumvictoria.com.au/planetarium/discoverycentre/skynotes/
So when you were near the equator on the 29th December the crescent moon in the early evening would be waxing (just after a new moon) and would be halfway between facing left and right, just like a boat.The red/orange colour is due to atmospheric pollution, most likely due to volcanic ash or bush fire smoke.
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Hi Lynne, the bright object next to the Moon last Saturday was Venus. Just below it was the planet Mars, which is slightly orange/red in colour and not very bright. There is also a bright star called Spica very near as well, but this is nowhere near as bright as Venus. You can find more info in the Planetarium Skynotes.
Hi Josh, Imogen, Leila, Sam, Alycia and Obi,
The colour of the Moon is very subtle: it has soft shades of grey, black and white, and regions of browns, blues and yellows. We generally say there are four phases of the Moon. New, First Quarter, Full, and Last Quarter. See the Moon Phases page of our website.
It is actually possible to see the whole Moon during the crescent moon phase. Sometimes there is so much light reflected from the Earth (Earthshine), that it lights up the part of the Moon that is not lit up by the Sun: we see the bright crescent Moon as well as the pale remainder of the Moon. As the Moon phase moves towards the Full moon, the Moon is so bright you can no longer see the arthshine on the Moon. The Moon has to be in the right position for the Earth to reflect the Sun's light onto the Moon's night side; this only happens just after the New Moon. This is called the Da Vinci Glow. You can find out more about it on the NASA website.
The diameter (width) of the moon is 3475.6 km (0.272 x that of Earth). The moon is (on average) 384 400 km from the Earth. The Moon does not have a moon of its own. You can learn more about The Moon on our website.
your answer about the moon phases always appearing the same every place on earth is misleading! The direction the crescent moons appear to be facing is actually...
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