Even if they continue at the current rate, the moon would only have lost 30 per cent of its water by mass when the sun becomes a red giant in 6 billion years. (newscientist.com)
Moving on, the sun will become a red giant in about 5 billion years. (treehugger.com)
Low - mass stars also become red giants towards the end of their lives, expanding and cooling at the surface. (scienceinschool.org)