2 launched on 19 th jan 2006 orbits 39.5 au from sun (1 au is average earth-sun distance) journey of...
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3 Discovered 26 th Jun 2014 by HST Magnitude +26 Orbits 44.2 AU from Sun, Period 293 years Low inclination and eccentricity – classic KBO Estimated diameter km Flyby on either 31 st Dec 2018 or 1 st Jan AU from Sun at flyby Where Next?TRANSCRIPT
Next Horizons?
Dr Paul A Daniels, Guildford Astronomical Society
New Horizons – Pluto
2
• Launched on 19th Jan 2006• Orbits 39.5 AU from Sun (1 AU is average Earth-Sun distance)
• Journey of 3,463 days = 9.48 years• 4,760,000,000 km journey (~3 billion miles)• Pluto flyby on 14th Jul 2015 at 12,500 km• 33.39 AU = 4.5 light-hours from Sun• Where next?
New Horizons – 2014 MU69
3
• Discovered 26th Jun 2014 by HST• Magnitude +26• Orbits 44.2 AU from Sun, Period 293 years• Low inclination and eccentricity – classic KBO• Estimated diameter 30-45 km• Flyby on either 31st Dec 2018 or 1st Jan 2019• 43.4 AU from Sun at flyby• Where Next?
To Infinity and Beyond?
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• Where would we like to go?– Nearest star!– ‘Interesting’ star!!– Earth-like exoplanet!!!– Across the galaxy!!!!– Another galaxy!!!!!
• Can we?
To Infinity and Beyond?
5 Speed of light, c = 1 ly/yr
Destination Distance, d (ly) Time, t (yr) Speed, v (ly/yr)Pluto 0.00063 0.035 0.036
Proxima Centauri 4.24 2.866 2.959
Vega 24.04 6.825 7.045
Kepler-452b 1,400 52.081 53.763
Across Galaxy 100,000 440.162 454.378
Andromeda Galaxy 2,500,000 2,200.812 2,271.888
Destination Distance, d (ly) Time, t (yr)Pluto 0.00063 0.035
Proxima Centauri 4.24 2.866
Vega 24.04 6.825
Kepler-452b 1,400 52.081
Across Galaxy 100,000 440.162
Andromeda Galaxy 2,500,000 2,200.812
Destination Distance, d (ly)Pluto 0.00063
Proxima Centauri 4.24
Vega 24.04
Kepler-452b 1,400
Across Galaxy 100,000
Andromeda Galaxy 2,500,000
𝑑=12 𝑎𝑡
2𝑡=√2𝑑/𝑎𝑣=𝑎𝑡
• Let’s assume we can maintain a continuous acceleration of 1g = 9.81 m/s2 = 1.0323 ly/yr2
Travelling Relatively
6
• Special relativity becomes important!
Time on rocketMass of rocket
𝛾=1
√1−(𝑣𝑐 )2
Travelling Relatively – Flyby!
7
Destination Distance,d (ly)Time on
Earth, t (yr)Time on
Rocket, T (yr)Speed at Destination,v (ly/yr)
Pluto 0.00063 0.035 0.035 0.03603439122399
Proxima Centauri 4.24 5.120 2.296 0.98248961191519
Vega 24.04 24.992 3.827 0.99924629467535
Kepler-452b 1,400 1,400.971 7.736 0.99999975987502
Across Galaxy 100,000 100,000.971 11.879 0.99999999995287
Andromeda Galaxy 2,500,000 2,500,000.971 15.004 0.99999999999993
• Special relativity becomes important very quickly!
• But… this for a fast flyby – no slowing down!• Almost no time to view destination• Radio signals back to Earth highly red-shifted
Travelling Relatively – ‘Loiter’
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Destination Distance,d (ly)Time on
Earth, t (yr)Time on
Rocket, T (yr)
Pluto 0.00063 0.049 0.049
Proxima Centauri 4.24 5.869 3.545
Vega 24.04 25.909 6.380
Kepler-452b 1,400 1,401.940 14.127
Across Galaxy 100,000 100,001.942 22.413
Andromeda Galaxy 2,500,000 2,500,001.942 28.663
• Suppose we want to slow down to arrive at our destination at low speed?
• This is just ‘fiddling with numbers’ – what about the engine and fuel?
Travelling Relatively – Engine
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• Consider our options…– Chemical fuel– Nuclear fuel– Matter/Anti-Matter Annihilation– Gamma-ray Lasers (Grazers)– Star-Trek
• Warp drives• Wormholes• Black-hole slingshots
Travelling Relatively
10
Destination Distance,d (ly)Fuel Mass perkg of Payload
Pluto 0.00063 0.05 kg
Proxima Centauri 4.24 37.52 kg
Vega 24.04 713.16 kg
Kepler-452b 1,400 2,085.13 tonnes
Across Galaxy 100,000 10,609,412.00 tonnes
Andromeda Galaxy 2,500,000 6,630,635,300.00 tonnes
• Assume we can convert matter to energy with 100% efficiency!
• How much matter do we need?
Travelling Relatively
11
• Engine/Fuel not possible!– Wait for Star Trek solution?
• Slower travel possible (<1g)– Robotic Missions Only?– How many human generations?
• Shielding is an issue!– Interstellar dust– Cosmic Microwave Background
• Returning signals to Earth– Size of dish and power required– Delay between departure and signals returned!
𝑐=𝑠𝑝𝑒𝑒𝑑𝑜𝑓 h𝑙𝑖𝑔 𝑡 Inspired by ‘The Relativistic Rocket’
http://math.ucr.edu/home/baez/physics/Relativity/SR/Rocket/rocket.html