#!/usr/bin/python3
# ===================================================================
# Calculate travel time to the nearest star
#
# ---------- data from web: August, 2021 ----------------------------
# voyager 1 voyager 2
# distance from earth (miles) 14,276,683,071 11,830,925,074
# distance from sun (miles) 14,297,913,021 11,889,966,250
# speed (mph) 30,000 35,000
#
# nearest star: Proxima Centauri is 4.246 light years
# ===================================================================
light_year = 5.879E+12 # miles
hours_per_year = 365 * 24 # hours
# ---- calculate distance to nearest star in miles
distance_to_star = light_year * 4.246
# ---- voyager travel time to nearest star in years
v1_time = distance_to_star / 30000 / hours_per_year
v2_time = distance_to_star / 35000 / hours_per_year
print()
print('---- travel time to Proxima Centauri ----')
print()
print(f'Voyager 1 {round(v1_time,2)} (years)')
print(f'Voyager 2 {round(v2_time,2)} (years)')
print()