Betelgeuse

Betelgeuse is 650 light years from Earth so it takes light 650 years to reach us.  It is expected to blow up as a supernova sometime in the next 1 million years.  If the explosion happened in the Year 3000 AD, then we will see the light arrive in the year 3650 AD, 650 years AFTER the event occurred. 

1 light year is 9.3 trillion kilometers, so multiply this by 650 to get the distance to Betelgeuse of 650 x 9.3 = 6045 trillion kilometers, which we can re-write as 6 thousand trillion kilometers.  The actual name for one thousand trillion is one quadrillion, so we might also write Betelgeuse’s distance as 6 quadrillion kilometers. 

Source: https://spacemath.gsfc.nasa.gov/

The Nearest Stars to the Solar System

Rank	Star Name	Distance (Light Years)
1.	Proxima Centauri	4.22
2.	alpha Centauri B	4.40
3.	alpha Centauri A	4.40
4.	Barnard's Star	5.94
5.	Lalande 21185	8.31
6.	Sirius	8.60
7.	Ross 154	9.69
8.	Epsilon Eridani	10.5
9.	Lacaille 9352	10.7
10.	Ross 128	10.9
11.	61 Cygni A	11.4

昨天開始看伊坂的《白兔》，書中有一位獵戶座專家折尾折尾(おりお おりお)，然後又提到獵戶座的腋下參宿四距離地球「只有」640光年，我就想，嗨嗨，伊坂你漏掉了「萬」字吧，翻查一下資料，原來真是這麼近的。最近的半人馬座比鄰星只有4光年而已，相信不久的將來人類可以乘Tesla前往旅行哪。