Archive for the ‘Astrophysics’ Category

Otherworldly Voices   17 comments

What Would Your Voice Sound Like On Other Moons and Planets?

 

Scream, shout and yell into the vast and infinite realms of space in the ever-optimistic hope that someone or something might just hear you and do you think anyone or anything will cheerily respond to you? Maybe. But it always depends on whether anyone or anything can hear you!

originalCShouting your head off on another world doesn’t guarantee the noisy and well-loved sound of your terran-based vocal cords will resound in quite the same way in the atmospheres of other worlds comfortably nestled amongst the stars.

 

On the cosy home world of Earth sound whizzes happily and easily through the atmosphere thanks to a distinct lack of vibrations being absorbed by our gassy air. This is one of the particularly pleasing results of lots of nitrogen and just a tiny scrap of molecules of the carbon dioxide variety. The other handy bonus is of course that we can breathe…. Minor detail but worth a mention Be right back

Things start to get a little bit weird however, should you be posturing and screaming on worlds that are clearly not Earth. Different worlds, different atmospheric densities and all that scientific, technical stuff. Disappointed smile

Most of us are probably at least vaguely aware, (don’t worry if you’re not, maybe for the best!), that “in space no-one can hear you scream!) This detail tends to apply too, on the majority of worlds in space. By and large they don’t have any atmospheres at all, and the ones that do have ridiculously thin and weedy atmospheres that contain so few gases that it would be impossible for them to carry even a single stingy little sound wave. Not that this would worry you overly much as you wouldn’t be able to breathe anyway and therefore wouldn’t be alive to be annoyed by it. If you happened to be a planetary native of that particular world specially adapted to create vocalisations on a super-sonic sound scale, of the nature that would shatter lesser worlds into a zillion pieces then you might just about manage to make yourself heard in some shape or form. Although it would most probably end up sounding something more like a whispering little sound in the vast void of outer space. Winking smile

The SKA Telescope   34 comments

The Square Kilometre Array

Out of the Darkness, Into the Light

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Astronomy allows us to see back in time because the light waves from distant stars and galaxies that reach our current telescopes take a long time to do so and what we see is from a very distant past. SKA (the Square Kilometre Array) will be the most powerful radio telescope we have built, and will see back to when the first galaxies and stars formed, and will make pictures from radio waves rather than seeing light waves. This will allow objects to be discovered that would otherwise remain invisible and impossible to know of.

Expected to collect more data in one week clip_image003than previous attempts have done in the whole of history it will have the means to survey the sky 100,000 times+ faster than ever before. By the time construction of the array is completed it will include 4,400 dish antennae and flat arrays, 2,200 of which will be situated in the central 5km-wide core area. Thousands of remaining arrays will be grouped together in “stations” spanning 3,000 km (size of a continent) from the core.

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The SKA Array will likely be based in South Africa or Australia; a decision will be made in 2012. If Australia was to be chosen SKA would spread right across the mainland, into Tasmania and New Zealand.

International project, also including several European countries, which will revolutionise our understanding in several areas of physics, including general relativity, (how gravity bends spacetime) planet formation, understanding magnetic fields, and cosmology. One of the most important projects will involve measuring the nature of dark energy which it is thought makes up 73% of the universe, because of the vast expanses SKA will be able to survey.clip_image009

May provide answers to fundamental questions about nature, origin and evolution of universe.

The SKA will be able to detect extremely weak extra-terrestrial signals and may even spot other planets capable of supporting life. Astrobiologists will use SKA to search for amino acids, the building blocks of life by identifying spectral lines at specific frequencies. The SKA array is sensitive enough to be able to detect similar types of radiation to that emitted from our TV broadcasts, radar, and mobile phones. If there proved to be an advanced alien race existing somewhere out in the universe contact could occur by such means. By 2024 the construction will be complete and the fun will begin!

Flying Close To Another Sun   48 comments

Project Icarus ~ Flying Close To Another Star

 

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Icarus and Daedalus in Mythology

Icarus and Daedalus were characters from ancient Greek mythology. Icarus’s father Daedalus was a famous architect, inventor and master craftsman. In order to escape imprisonment by King Minos of Crete Daedalus built wings for himself and Icarus, out of feathers, held together with wax. Daedalus warned his son not to fly too close to the sun, as it would melt his wings, and not too close to the sea, as it would dampen them and make it hard to fly. Caught in the thrill of flying successfully from Crete Icarus became careless. He flew too close to the sun god Helios, “touching the sky” and the wax holding his wings together melted in the heat and he fell to his death drowning in the Icranian Sea, which was named after him. 

img_01Purpose of Project Icarus 

Project Icarus is a joint initiative with the Tau Zero Foundation and British Interplanetary Society (BIS). The aim of Project Icarus is to design and power an Interstellar probe to “touch the stars” and escape the boundaries of Earth. Over 30 years has now passed since its predecessor, the Daedalus Project. This was a BIS project in late 1970’s conducted over several years, to design an interstellar probe for a flyby mission to Barnards Star. In light of scientific and technological advances the time has come to re-assess the unique concept of the Daedalus design in the hope that such studies will bring closer the day when mankind reaches out to the stars.

Without such an assessment it is difficult to realistically project when and what might be possible, and exactly what will be involved to make it possible. The Project Daedalus study will inject a much needed dose of reality into what was previously nothing more than speculation on interstellar probes/travel. And whilst still at the design stage the Project Icarus concept is its successor that Tau Zero Foundation and BIS scientists are working on.

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Project Daedalus

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      • Began January 1973 as a study to determine the feasibility of Interstellar Space Flight
      • It was concluded in 1978 that Interstellar flight was possible
      • It would be powered by fusion rockets using radio-active pellets (Deutrium and Helium-3)
      • And ignited by electronic beams to create plasma to push Daedalus through space
      • Helium-3’s rarity on Earth would have meant 20 years of mining from Jupiter’s atmosphere by hot air balloon – supported by robotic factories
      • Designed to accelerate for approximately 4 years until speeds 12% speed of light were achieved, then to spend the next 46 years cruising

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      • 5 year design study that began 30 September 2009 with aim of creating a credible interstellar probe and supporting the vision of manned space exploration. 
      • Icarus has two design power options:

  1.     Fusion Propulsion Engines:

Microwaves would be used to heat plasma to approximately 600 million degrees. This would fuse hydrogen nuclei to create Helium and the hot charged particles it produced would provide the necessary thrust. Presently the engineering necessary to set off a fusion reaction is unrealistically high, but Icarus designers are considering an experimental plasma engine ~ Vasimi. Besides demonstrating the concept it could also reduce to less than 40 days, the 9 month journey to Mars.

  2.      hypothetical_antimatter_rocket_NASA's Marshall Space Flight Cenyter Antimatter driven sail for deep space mission to the Kuiper Belt Cred Hbar TechnosLLCElizabeth laguna Antimatter Propulsion Engines:

300 X more powerful than nuclear fusion reactions. The matter~antimatter reaction occurring in the antimatter engine would be the ultimate power source for Interstellar crafts. 100% mass of an Antimatter reaction is converted into energy. This releases billions of times more energy than a similar quantity of converted rocket fuel.

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        • It would travel at minimum 18 per cent of the speed of light (FAST!) to the nearest star, Epsilon Eridani, an orange sun-like star ~ 10.7 light years away
        • Communicating with it would necessitate bending radio signals around the Sun.
        • This involves a process known as Gravitational Lensing where light (radio waves) are bent around massive objects like stars and galaxies. In Icarus’s case ~ THE SUN. The same effect can be seen when light passes through a prism. At the focal point the signal is drastically amplified, making communication distance between Icarus and Earth much shorter.
        • It has however been conceded that it would not be likely to launch till the end of next century and even at the above speeds still take decades to reach its destination.

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There are many different approaches necessary when striving for Inter-stellar flight ranging from the apparently simple Solar Sail to the warp drives of sci fi. Project Icarus is a half-way point taking an in-depth, no holds barred look at the “edge of projected technology in the context of a realistically demanding inter-stellar mission. It is a sequel to the seminal 1978 “Project Daedalus” of the BIS.”(Marc Millis – Icarus Consultant and Former Project Manager of the NASA Breakthrough Propulsion Physics Project, March 2010, and President of the Tau Zero Foundation)

Solar Sails   14 comments

Solar Sail Space Crafts

 

Space craft propelled directly by the power of sunlight (solar cells are indirect power).

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Two projects are set for launch this year:-

  •   IKAROS – launched by Japanese Space Agency JAXA
  •   SOLARSAIL-1 by US based Planetary Society

(These are demonstrations to show that it can work, but they are very tiny!)

Solar Sail Craft Basics

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Constructed from Gossamer – thin reflective sails capture photons

  •   Photons are packets of energy that make up sunlight

The sails gain momentum from the photons as they are reflected from their surface. Energy gained pushed the craft forwards gently. The force of sunlight is very little but this is fine as their CO2 acts against it in the vacuum of space.

Future sails could be made of nanotube mesh – 30 times lighter, and could increase acceleration dramatically.

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Travel and Speeds

With the Sun set to shine for a good billion years or so yet, it can be considered an endless fuel supply therefore a Solar Sail Craft could in theory, reach speeds of hundreds of kilometres per hour making travel to Pluto a mere three years and to the outer limits of the Solar System years rather than decades. NASA’s Voyager craft took thirty years to reach these limits. A Solar Sail Craft launched today would pass it in ten years.

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Other Solar Sails

They would need sails 100m across and a boost from a large and unrealistically expansive laser system as the Sun’s energy decreases with distance. However laser-boosted systems could see a Solar Sail Craft travelling at speeds of up to 20% speed of light (60,000km/hr or 45,000mph) every second. This would make visiting neighbouring stars in our lifetime our best possibility.

Brief History

  1. Concept first proposed by German astronomer Johannes Kelper in seventeenth century
  2. 1862 Scottish physicist James Clark Maxwell discovers that light exerts a pressure on a surface.
  3. 1867 Jules Vernes suggests light pressure could provide a mechanical means of propulsion.

solarsail4. 1924 Russian scientist Fridrickh Arturovich Tsander wrote “For flight in Interplanetary Space I am working on the idea of flying using tremendous mirrors of very thin sheets capable of achieving favourable results.“

Mariner Probe

5. 1971 When NASA’s probe Mariner ran low on steering thrusters fuel en route to Venus engineers angled its solar panels into the Sun and used solar radiation pressure to steer it back on course.

Cosmos-1

6. 2005 Cosmos-1 a Solar Sail designed by US Planetary Society failed its test, due to rocket failure on launch vehicle, resulting in it being unable to reach its intended orbit.

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7. 2008 NASA’s Nanosail-D mission, to test the Solar Sail’s deployment techniques. Lost during launch failure.