Showing posts with label moon. Show all posts
Showing posts with label moon. Show all posts

09 February 2015

Earth-Moon ballet

This animation of the Earth-Moon system was made available by the BBC. The animation was produced by NASA.

This has to be seen by as many people as possible; it truly puts our planet into a different perspective. While you watch, remember that the entire Earth-Moon system that you see here is itself orbiting around the sun, which in turn is orbiting the centre of our Milky Way galaxy, which in turn is heading slowly towards an interaction with the Andromeda galaxy. If that doesn't inspire awe, nothing will!

24 April 2013

Space, a new era

A new age is beginning in space commerce. After a little history this article considers where things may go next in timescales of ten, twenty and a hundred years. This is no longer purely science fiction, it is becoming technological fact. It's possible to foresee voyages to the stars a hundred years from now.

Apollo 4 on the pad
Yes, we really are at the beginning of a new era in spaceflight. Until recently almost all efforts in space were the preserve of governments or multinational bodies like the European Space Agency (ESA).

In a few areas private companies were able to play a role, but the funding was mostly government based.

The only real exception has been for communications satellites, and even these had to be flown on rockets designed and built for governments.

In this article we'll look at how the situation has been changing, especially over the last five years.

Early history - I was nine-years-old when Sputnik 1 was launched by the Soviet Union in October 1957. I remember hearing its bleeping tone on the radio and noticing how anxious Mum and Dad seemed that the Russians rather than the Americans had achieved this feat of engineering.

Of course, America wasn't far behind; though early European cooperation in rocketry failed.

In April 1961 Yuri Gagarin flew on Vostok 1 and before long orbital trips seemed almost routine. The Americans landed Apollo 11 on the Moon in July 1969. Today we can add many more nations, an international organisation (ESA), and even a private company (SpaceX) to the list.

Commercial satellites - Commercial space businesses began with government contracts to construct rockets and build satellites. But the first businesses to make a profit from space were broadcasting and telecommunications companies.

Since then direct broadcast TV, weather satellites, earth resources, mapping, messaging, delivery tracking and global positioning (GPS) have become mainstream commercial applications. And military satellites, although not commercial in nature, are widely deployed and used by many national governments.

The space launch industry - With so many commercial satellite operators, it was clear that there was a  market for a commercial space launch industry.

Until recently those launchers have been funded and specified by governments, but now SpaceX, a number of other companies and some cooperative ventures such as the United Launch Alliance (ULA) are looking to make a profit by selling launch services. This includes provision of the launch vehicles, payload integration, fuelling, pad infrastructure, and managing the launch itself.

Virgin Galactic - Virgin is close to providing sub-orbital short hops into space. They plan to cater for space tourism as well as offering research flights. For the first time scientists and engineers will be able to fly with their experiments regularly and return them reliably. This service may replace throw-away sounding rockets.

Other companies are working on sub-orbital flight too, but Virgin are very close. Their spacecraft (SpaceShipTwo) is about to begin powered test flights.

SpaceX - Elon Musk's company already offers two sizes of commercial launcher (Falcon 1e and Falcon 9) and is close to testing Falcon Heavy for even larger payloads. They are also using their Dragon cargo ship to fly regularly to the International Space Station (ISS), are working hard on a crewed version of Dragon.

DragonLab is a free-flying commercial venture to provide a weightless platform for science and technology. Any organisation can book space on DragonLab knowing that their payload can be recovered and flown again as often as required.

A further project (Grasshopper) is developing the technology to safely land and re-use Falcon 9 rocket stages. And in the more distant future SpaceX has ambitions to see a viable human colony established on Mars.

Bigelow - Bigelow Aerospace has two prototype inflatable space habitat modules in orbit, is planning to attach one to the ISS for testing by NASA, and plans to offer orbital accommodation for science as well as for tourism.

Mars OneMars One is a non-profit foundation based in the Netherlands. They hope to colonise Mars and pay for it by a combination of donations, sponsorship and TV contracts. The plan is to send four people to Mars in 2023 with four more arriving every two years after that. These are one way trips. Mars One is now open for applicants and is signing contracts for initial design studies.

Asteroid mining - At least two companies have been created recently with a view to the commercial exploitation of asteroidal materials. Asteroids are rich in rare and precious metals as well as volatiles in the form of ices.

Where is it all leading? - This really is a special time in spaceflight. We are progressing from state funded and controlled projects at relatively small scale and high cost, towards commercial operations taking humankind and our machines further and doing so profitably.

The immediate future offers the prospect of short hops into space for anyone with £20 000 to £30 000 to spare, a reusable Falcon 9 first stage substantially reducing the cost to orbit, and commercial access to low Earth orbit (LEO) for both crewed and uncrewed spacecraft. This is likely to include small capsules like SpaceX's Dragon and much larger volumes such as the Bigelow inflatable modules. Much of this will happen in the next ten years.

In the longer term we can expect commercial operations to develop raw material supplies from Asteroids, as well as small colonies on Mars and perhaps the Moon too. For this we may be looking at a twenty year timescale.

But make no mistake, once this process has begun there will be no stopping it. We are probably heading for a Solar System wide civilisation within the next century. Children born today will find it quite normal to watch and read material created on a different planet or in orbit elsewhere around our local star.

And once the outer planets have been reached it will be only a matter of time before our descendants start to consider how best to reach other stars. Perhaps they will send out self-sufficient colonies based on and inside modified asteroids.

Questions:

  • If humans colonise space, how will that affect society, faith, and the future?
  • Are you going to sign up for Mars One's one way trip to Mars? (I'm not!)
  • How would you feel if your children or grandchildren were living on Mars?
  • If the cost comes down enough, would you fancy a sub-orbital hop into space?

See also:




31 January 2013

Full Moon rising

We take an unusual look at our nearest neighbour in the Solar System, the Moon. Watch it rise, with some unanticipated activity in the foreground, and then ponder some things you may not have considered before.

Full Moon
This remarkable video by Australian Mark Gee shows the Moon rising in an unexpected way in the New Zealand evening sky. There are many things to notice about this scene and I'll go through them below the embedded video. But please watch it first, you will not be disappointed!

You can watch it right here on the page. But I strongly recommend that you click the full screen control (the four arrow symbol at bottom right) and if you have a good internet connection, also make sure you view it in HD.

Come back here after you watch it, scroll down the page a little, and we'll talk about what you have just watched.



Big Moon or small people? - Mark was using a good telephoto lens here. Imagine looking at a nearly full Moon rising above a distant hill line with people walking along the ridge. They'd be silhouetted against the bright Moon but they be almost too small to see. In this shot both the Moon and the people are magnified by the same amount.

Fuzzy and shimmering Moon - Look at the edge of the Moon. Do you see the constant disturbance of what would should be a sharp and smooth edge? This is due to temperature differences along the line of sight. The density and refractive index of the air depend on temperature. You can see the same effect above a road surface on a hot day, or above a hot roof. Objects behind the shimmering air wobble and move continually.

Steady people - Take a careful look at the people and the grass and the fence line. Are they shimmering too? No! But why not? The answer may not be immediately obvious. There's a great distance of air between the camera and the Moon, much less between the camera and the people. Most of the disturbed air is way beyond the people, between them and the Moon.

Where's the Sun? - As a full Moon rises, the Sun sets on the opposite horizon. At times other than full Moon this is not the case. Sometimes both Sun and Moon will be in the sky at the same time. At other times both may be below the horizon. New Moon, when they are both in the same part of the sky, is a good time for astronomers because the sky is nice and dark all night long.

So why is there no sunlight? - If the Sun is setting as the full Moon rises, why can't we see its light on the people and the vegetation? If you'd been there at the time you'd have thought the sky was quite light, there may indeed have been a lovely glow behind you as you looked at the Moon. But the full Moon would have been brighter than the remaining light from the Sun and the camera was set to record the Moon, not the people.

Also, this Moon is not perfectly full. Notice that the right-hand edge of the Moon is sharper and brighter than the left-hand edge. The Sun had already dipped below the horizon before the Moon made its appearance.

Isn't the Moon moving the wrong way? - In the UK where I live, the Moon moves steadily to the right as it rises. But this Moon moves steadily left! Why? It moves to the right in the USA too, and indeed anywhere north of the equator. But in the southern hemisphere the Moon moves left. If you're a northerner imagine standing on your head. Now which way would the Moon seem to move - left or right? It moves from east to west wherever you live.

And it's upside down! - Indeed it is. But so are Australians. Or we northerners are, it depends who you ask.

It's more yellow than I expected - That's because it's made of well-matured cheese. I thought everyone knew that.

The real reason is that we are looking at it through a lot of atmosphere. Air scatters blue light (which is why the daylight sky looks blue). Near the horizon both the Sun and the Moon appear yellow or orange, or even reddish. As they rise higher they have less and less air to shine through so the orange effect is lost and a Moon high in the sky appears white (though in fact it's a rather dark grey). The night sky is dark and the Moon appears intensely white because of the high contrast.

More about the video - Mark Gee tells the story of making this video in his own words; it's well worth reading so do go and take a look. Mark's video was made on 28th January and featured on 'Astronomy Picture of the Day' (APOD) on 30th January.

Questions:

  • We live in a truly astounding universe. What is the most amazing thing you have ever seen?
  • Are you surprised to see how fast the Moon rises?
  • How do you feel when you watch this video?

See also:

30 October 2011

IMAGE - The moon

(Click the photo for a larger view)
A dark evening sky with a bright new moon - Photo taken 29th October 2011
The sun had set some time earlier and the sky was getting dark. The bright young moon was following the sun and would soon be setting too, but for a while it hovered amongst the clouds. Beautiful!

Click the 'image' label below to see other image posts.

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