<p>As the Sun's mass is reduced and it's gravitational attraction is thus reduced the Earth will <strong>slowly</strong> spiral out from the Sun and yes slow down (to preserve angular momentum). But the effect is ridiculously small (do the math yourself) it will not be measurable directly.</p>

CC BY-SA 3.0
2016-06-15T10:06:56.063Z
2016-06-15T10:06:56.063Z
James Screech
<p>The sun is slowly losing mass, partly from the conversion of mass to energy (which then escapes as neutrinos and light) and partly from the solar wind (particularly in coronal mass ejections). Solar wind accounts for a loss of about 1.5 million tons per second, fusion accounts for 4 million tons per second. However compared to the mass of the sun (about 2 million billion trillion tonnes) it is tiny</p>

<p>The Earth isn't on rail tracks, so as the sun loses mass, it will change its orbit. Each year it moves about 1.6cm further from the sun, and since more distant orbits are slower, it will also slow down. After a billion years the Earth will have slowed to 99.999% of its current speed.</p>

CC BY-SA 3.0
2016-06-15T18:55:50.153Z
2016-06-15T18:55:50.153Z
James K
<ul>
<li>The Sun is losing some of its mass during explosions.</li>
<li>The Gravitational force between Sun and Earth will change (probably decrease).</li>
<li>If Earth maintains its speed, it will change its orbit.</li>
<li>Hence, Earth will decelerate</li>
</ul>

<p>Is this true?</p>

CC BY-SA 3.0
2016-06-15T10:02:16.473Z
The Sun is also losing mass due to it being converted into energy (about 4 million tonnes a second)
James Screech
<orbit><solar-system><earth>
Is Earth slowing down in order to stay on its orbital track?
Raed
# Is Earth slowing down in order to stay on its orbital track?

(Asked by: username_0 on 2016-06-15)

* The Sun is losing some of its mass during explosions.
* The Gravitational force between Sun and Earth will change (probably decrease).
* If Earth maintains its speed, it will change its orbit.
* Hence, Earth will decelerate

Is this true?

**Tags:** orbit, solar-system, earth

> **Comments:**
> **username_1**: The Sun is also losing mass due to it being converted into energy (about 4 million tonnes a second)  

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## 2 answers

### Answer by username_2 on 2016-06-15. Score: 6 | Accepted answer

The sun is slowly losing mass, partly from the conversion of mass to energy (which then escapes as neutrinos and light) and partly from the solar wind (particularly in coronal mass ejections). Solar wind accounts for a loss of about 1.5 million tons per second, fusion accounts for 4 million tons per second. However compared to the mass of the sun (about 2 million billion trillion tonnes) it is tiny

The Earth isn't on rail tracks, so as the sun loses mass, it will change its orbit. Each year it moves about 1.6cm further from the sun, and since more distant orbits are slower, it will also slow down. After a billion years the Earth will have slowed to 99.999% of its current speed.


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### Answer by username_1 on 2016-06-15. Score: 5

As the Sun's mass is reduced and it's gravitational attraction is thus reduced the Earth will **slowly** spiral out from the Sun and yes slow down (to preserve angular momentum). But the effect is ridiculously small (do the math yourself) it will not be measurable directly.


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