A Metre in Light-Years

Q. A light-year is the distance light goes in a year. What is one metre in light-years? expects 1.06 × 10⁻¹⁶ ly

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The web of concepts

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The equations it used

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Check an answer

Q. A light-year is the distance light goes in a year. What is one metre $l = 1$ m in light-years?

The playground

Inputs

metre

l

1.00 m

Outputs

light years

l

The solution

Solved with Units

Given

$l = 1$ m

Find $l$ .

Working

$l = 1$ m $= 1.05700083 \times 10^{−16}$ ly
$l \approx 1.06 \times 10^{−16}$ lyto 3 significant figures

Conclusion

A light-year is a length, the distance light goes in a year, so one metre is a tiny fraction of it.

The Ruby

1require_relative "../physics"23question :a_metre_in_light_years do4  kind :numerical5  describes "A light-year is the distance light goes in a year. What is %{metre} %{light_years}?"6  given metre: "1 m", as: "one metre"7  asks light_years: "in light-years"8end

1require_relative "../questions/a_metre_in_light_years"2require_relative "../science/units_and_measurement/units"34solve :a_metre_in_light_years, using: Units do5  take metre: :l6  take light_years: :l7  answer find_value(:light_years, in: "ly", figures: 3)89  conclusion "A light-year is a length, the distance light goes in a year, so one metre is a tiny " \10             "fraction of it."11end

1require_relative "../solutions/a_metre_in_light_years"23play_with :a_metre_in_light_years do4  title "A Metre in Light-Years"5end

The laws

quantity	written	units	within	from
speed of light	$c$	m/s	—	Units
avogadro constant	$N_{A}$	mol⁻¹	—	Units
length	$l$	m	0 … ∞	Units
mass	$m$	kg	—	Units
time	$t$	s	0 … ∞	Units
electric current	$I$	A	—	Units
temperature	$T$	K	—	Units
amount of substance	$n$	mol	—	Units
luminous intensity	$I_{v}$	cd	—	Units
arc length	$s$	m	—	Units
radius	$r$	m	0 … ∞	Units
plane angle	$θ$	—	—	Units
area	$A$	m²	—	Units
solid angle	$Ω$	—	—	Units
light time	$t_{light}$	s	—	Units
light distance	$d_{light}$	m	—	Units
number of entities	$N$	—	—	Units
baseline	$B$	m	—	Units
distance away	$D$	m	—	Units
parallax angle	$θ_{p}$	—	—	Units

θ = \frac{s}{r}

arc over radius

Ω = \frac{A}{r^{2}}

area over radius squared

d_{light} = c \cdot t_{light}

distance at light speed

N = n \cdot N_{A}

entities in moles

θ_{p} = \frac{B}{D}

baseline over distance