Relative distance to nearest star?

[EvolutionaryPS]

If the moon was 1 meter away is my calculation correct to say the nearest star would be 104,599km away?
Cheers Paul

[Robh]

104,599 x 1000 x 384,399km / (9.46 x 10^12 km)

= 4.25 light years

Close enough!

Regards, Rob

[EvolutionaryPS]

Great thanks, it is extraordinary.

[Startrek]

Paul,
Download Stellarium ( it’s free )
It can answer all your questions about types of celestial objects, location of any celestial object every second of the year , brightness and sooooo on .....
It’s your handbook and road map to the Universe
The latest releases are tremendous with more detail and info than ever before
Cheers
Martin

[mura_gadi]

Hello,

Try looking for a interactive version of the "Sloan Digital Sky Survey"(Celestia is one), it is a 3d model that allows you to fly/travel between any known celestial objects you like within a defined distance from us.

It allows you to set the speed you wish to travel at between objects etc and gives you a simulation of the trip. (suddenly saying a millions of miles an hour just doesn't cut it for speed.)

Not really a star map for alt/az etc, but great for spatial orientation of whats' around us and the zoom out is impressive...



Steve
Ps. Another way to look at it, a little over 1 second for light to travel from the Earth to the moon, over four years for light from the nearest star... (go roughly 31.5m seconds a year)

The moon's diameter is about 3474km, distance from Brisbane to Geraldton WA as the crow flies is 3753km, Sydney-Perth 3290km, so you basically looking at an Australian sized object at 384k or so km. Or how big Australia would look after you had been travelling for 1light second after leaving Earth.

[xelasnave]

So how long to get there under our current limitations?
Alex

[raymo]

As far as I recall, the Voyagers are coasting along at 40,000 klm/hr, and if
aimed at Alpha Centauri, would take about 75,000 yrs to get there. We could send a much faster vehicle
which would continue to slowly accelerate for many years, but I'm thinking that the figure would still be
somewhere in the 10-20,000 yr range.
raymo

[EvolutionaryPS]

There is theoretical nuclear powered craft that could take 100 years but current technology tens of thousands years at voyager 1 speed it'll take about 73,000 years.

[Buck]

Hello Alex,

A few years ago, I set up a "poster" to display at Science Week at the ASSA stand. It was aimed at school students to give them an idea of the vastness of space at a (hopefully) basic level that they could relate to.

Here it is ...

DISTANCES IN SPACE

Distance to the nearest Star System (naked eye visibility) outside our Solar System.

Name: Alpha (1) Centauri – the brighter (1) of a double star system (the other is called Alpha (2) Centauri) “pointing” toward the Southern Cross. This star is also known as Rigil Kentauris or Toliman. There is a star slightly closer to us (Proxima Centauri), but it is not visible to the naked eye.

Distance: 4.36 light years (ly)

Distance that light travels in one (1) second is 300,000 kilometres (km) rounded (actual in free space is 299,792.458km)

So, 4.36 ly = 41,248,784,860,000 km – or – 41 quadrillion, 248 trillion, 784 billion, 860 million kilometres from Earth.

Let’s put that another way.

Are we there yet?

The speed limit on open roads in Australia is (generally) 100 kilometres per hour (100 km/hr).

How long would it take (at 100 km/hr) to travel to Alpha Centauri? (remember this is the closest visible star).

1. Distance (in km) ÷100 (speed in km/hr) = number of hours.

∴ 41,248,784,860,000 km ÷ 100 = 412,487,848,600 hrs.

2. Hours ÷ 24 = number of days

∴ 412,487,848,600 hrs ÷ 24 = 17,186,993,692 days.

3. Days ÷ 365.25 = number of years.

∴ 17,186,993,692 ÷ 365.25 = 47,055,424 years. (or 47 million, 55 thousand, 424 yrs).

Humans, in our current evolutionary stage, have been on the Earth for approximately 2 million years. So, travelling at 100 km per hr, it would take about 23½ times longer to reach the nearest visible star, as modern humans have existed on Earth.

Remember, we are talking about the nearest visible star at 4.36 ly away. We can see the nearest spiral galaxy (Andromeda galaxy) with our naked eye, and that is about 2.5 million light years from Earth.

If we speed up from 100 km per hr to 300,000 km per second (the speed of light), then it will still take us longer to get to the Andromeda galaxy, than the time modern humans have existed on Earth!

Again this was the closest (spiral) galaxy to Earth. With modest optical aid (good binoculars), you can see galaxies that average about 65 million light years distance from Earth (in the Virgo group).

These galaxies are still “close” by astronomical standards, and yet the light from these galaxies, traveling at 300,000 km per second, has taken so long to reach us, that it started out when the last dinosaurs were becoming extinct!

And so on it goes ……….. to galaxies far, far away…….

[xelasnave]

Thanks for that Buck.:thumbsup::thanx:
I also like applying an approach that our craft can travel at 100 times the speed of light, to help out;) that demonstrates inter gallactic travel as in si fi is just a wild idea...M31 being then 20,000 to 25000 years away .,or if you burn only a gram of fuel per 100000 klms the wild payloads that come into play.
Thank you so very much for your contribution I certainly enjoyed it and no doubt as would others.
Alex

[Kal]

For the younger forum members possibly during their lifetime. Look up Breakthrough Starshot (https://en.wikipedia.org/wiki/Breakthrough_Starshot)


Breakthrough Starshot is a research and engineering project by the Breakthrough Initiatives (https://en.wikipedia.org/wiki/Breakthrough_Initiatives) to develop a proof-of-concept (https://en.wikipedia.org/wiki/Proof_of_concept) fleet of light sail (https://en.wikipedia.org/wiki/Light_sail) interstellar probes (https://en.wikipedia.org/wiki/Interstellar_probe) named Starchip,[1] (https://en.wikipedia.org/wiki/Breakthrough_Starshot#cite_note-CD-20160412-1) to be capable of making the journey to the Alpha Centauri (https://en.wikipedia.org/wiki/Alpha_Centauri) star system 4.37 light-years (https://en.wikipedia.org/wiki/Light-years) away. It was founded in 2016 by Yuri Milner (https://en.wikipedia.org/wiki/Yuri_Milner), Stephen Hawking (https://en.wikipedia.org/wiki/Stephen_Hawking), and Facebook founder Mark Zuckerberg (https://en.wikipedia.org/wiki/Mark_Zuckerberg).[2] (https://en.wikipedia.org/wiki/Breakthrough_Starshot#cite_note-2)[3] (https://en.wikipedia.org/wiki/Breakthrough_Starshot#cite_note-3)
A flyby mission has been proposed to Proxima Centauri b (https://en.wikipedia.org/wiki/Proxima_Centauri_b), an Earth-sized (https://en.wikipedia.org/wiki/Terrestrial_planet) exoplanet (https://en.wikipedia.org/wiki/Exoplanet) in the habitable zone (https://en.wikipedia.org/wiki/Habitable_zone) of its host star, Proxima Centauri (https://en.wikipedia.org/wiki/Proxima_Centauri), in the Alpha Centauri system.[4] (https://en.wikipedia.org/wiki/Breakthrough_Starshot#cite_note-NYT-20160824-4) At a speed between 15% and 20% of the speed of light (https://en.wikipedia.org/wiki/Speed_of_light),[5] (https://en.wikipedia.org/wiki/Breakthrough_Starshot#cite_note-BR-20160412-5)[6] (https://en.wikipedia.org/wiki/Breakthrough_Starshot#cite_note-NYT-20160412-db-6)[7] (https://en.wikipedia.org/wiki/Breakthrough_Starshot#cite_note-7)[8] (https://en.wikipedia.org/wiki/Breakthrough_Starshot#cite_note-BR-20160412about-8) it would take between twenty and thirty years to complete the journey, and approximately four years for a return message from the starship to Earth.
The conceptual principles to enable this interstellar travel project were described in "A Roadmap to Interstellar Flight", by Philip Lubin of UC Santa Barbara (https://en.wikipedia.org/wiki/University_of_California,_Santa_Bar bara).[9] (https://en.wikipedia.org/wiki/Breakthrough_Starshot#cite_note-LubinRoadmap-9)[10] (https://en.wikipedia.org/wiki/Breakthrough_Starshot#cite_note-10) Sending the lightweight spacecraft involves a multi-kilometer phased array (https://en.wikipedia.org/wiki/Phased_array) of beam-steerable lasers (https://en.wikipedia.org/wiki/Laser) with a combined coherent power output of up to 100 GW (https://en.wikipedia.org/wiki/Gigawatt).[11] (https://en.wikipedia.org/wiki/Breakthrough_Starshot#cite_note-11)

[Stonius]

I once did a scaled solar system walk with my boys. The entire solar system compressed into a 5km walk. That was fun. And eye-opening. It's best to start at Pluto, otherwise all the excitement happens at the beginning.



It's also fun to think about relative angular size for planetary observation. For example, if Jupiter were the size of a grapefruit, how far away would it have to be to have the same angular size? I'm sorry, I can't remember the answer right now, but i think it was like a kilometer?


Cheers,


Markus