<p>The speed of travel does not matter. The amount of rotations around Earth's axis matters when it comes to counting the amount of sunrises or sunsets on a travel around the Earth.</p>
<p>Assume that you are travelling once around the world. You depart westward, and it takes you 24 hours to once travel around the world. You depart 1 hour before Sunrise, and you stay <em>the whole time</em> of the trip 1 hour before sunrise. When you are back on your original location, the people who stayed there will tell you that a whole day has passed with sunrise and sunset and the next sunrise is about to happen in an hour. So you &quot;lost a day&quot;. You didn't really lose it - you also lived 24 hours. But you did experience <em>one sunrise less</em> than people staying on a fixed position on the globe due to the fact that you did one complete rotation <em>against the direction of Earth's rotation</em>. Would you have travelled East, you would have experienced two sunrises in that timeframe. You lose or gain a day only, if you count day as &quot;sunrise to sunset&quot; as that depends on the amount of rotations around Earth's axis you perform.</p>
<p>The argument stays true regardless of the speed of travel: if you travel West, you will have one sunrise less than a person remaining on the same place; and if you travel East you will experience one more.</p>

CC BY-SA 4.0
2024-01-17T14:39:19.437Z
Thank you.  I am not in any way a scientist like yourself. Just getting into this.  I understand the answer. Just - traveling westward- say at a slower speed- say 250 mph. As you "come around" and see the sun - it would be sunrise for you? As that I your "east"? And until you get back to the starting point- since traveling "west" - you would not see a sunset? Is that accurate? So whilst Megellan crew saw one less sunrise- they didn't see a sunset? Or am I totally wrong?
jacob kind
CC BY-SA 4.0
2024-01-14T05:57:02.133Z
2024-01-14T12:10:26.903Z
2024-01-14T12:10:26.903Z
planetmaker
<p>In the story of Magellan in which they circled the globe ,returning to Portugal to discover that they &quot;lost&quot; a day. As they were traveling westward. I don't get it. They were going so slowly in those times. Took 3 years. I get that they, were traveling west so the day was slightly shorter for them. But to end up exactly 1 day different? Puzzles me.</p>

CC BY-SA 4.0
2024-01-14T04:02:05.290Z
Traveling west would increase the duration of a day, not shorten it.
4NT4R3S
CC BY-SA 4.0
2024-01-14T05:16:50.100Z
How come this is an Astronomy question?
Nilay Ghosh
CC BY-SA 4.0
2024-01-14T07:30:08.480Z
What puzzles you?  They went around the world once and days are counted by how many times you go round.
James K
CC BY-SA 4.0
2024-01-14T09:00:49.880Z
@NilayGhosh Because horology and astronomy have been closely linked since ancient times. Until the 20th century, before the development of quartz crystal electronics, the most precise clock on Earth was the spinning Earth itself.
PM 2Ring
<orbit>
International dateline
jacob kind
# International dateline

(Asked by: username_0 on 2024-01-14)

In the story of Magellan in which they circled the globe ,returning to Portugal to discover that they "lost" a day. As they were traveling westward. I don't get it. They were going so slowly in those times. Took 3 years. I get that they, were traveling west so the day was slightly shorter for them. But to end up exactly 1 day different? Puzzles me.

**Tags:** orbit

> **Comments:**
> **username_1**: Traveling west would increase the duration of a day, not shorten it.  
> **username_2**: How come this is an Astronomy question?  
> **username_3**: What puzzles you?  They went around the world once and days are counted by how many times you go round.  
> **username_4**: @username_2 Because horology and astronomy have been closely linked since ancient times. Until the 20th century, before the development of quartz crystal electronics, the most precise clock on Earth was the spinning Earth itself.  

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## 1 answers

### Answer by username_5 on 2024-01-14. Score: 5 | Accepted answer

The speed of travel does not matter. The amount of rotations around Earth's axis matters when it comes to counting the amount of sunrises or sunsets on a travel around the Earth.

Assume that you are travelling once around the world. You depart westward, and it takes you 24 hours to once travel around the world. You depart 1 hour before Sunrise, and you stay *the whole time* of the trip 1 hour before sunrise. When you are back on your original location, the people who stayed there will tell you that a whole day has passed with sunrise and sunset and the next sunrise is about to happen in an hour. So you "lost a day". You didn't really lose it - you also lived 24 hours. But you did experience *one sunrise less* than people staying on a fixed position on the globe due to the fact that you did one complete rotation *against the direction of Earth's rotation*. Would you have travelled East, you would have experienced two sunrises in that timeframe. You lose or gain a day only, if you count day as "sunrise to sunset" as that depends on the amount of rotations around Earth's axis you perform.

The argument stays true regardless of the speed of travel: if you travel West, you will have one sunrise less than a person remaining on the same place; and if you travel East you will experience one more.

> **Comments:**
> **username_0**: Thank you.  I am not in any way a scientist like yourself. Just getting into this.  I understand the answer. Just - traveling westward- say at a slower speed- say 250 mph. As you "come around" and see the sun - it would be sunrise for you? As that I your "east"? And until you get back to the starting point- since traveling "west" - you would not see a sunset? Is that accurate? So whilst Megellan crew saw one less sunrise- they didn't see a sunset? Or am I totally wrong?  

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