If we don't detect metal rich dust around the other white dwarves, we might have to revise our thinking [about the dust's origin], ... The comet impact model looked pretty good 10 years ago, but it doesn't look so good anymore. There's still a lot of mystery  -   Ben Zuckerman     Quotes
If we don't detect metal rich dust around the other white dwarves, we might have to revise our thinking [about the dust's origin], ... The comet impact model looked pretty good 10 years ago, but it doesn't look so good anymore. There's still a lot of mystery Ben Zuckerman
 10 Years Mystery