Short-period comets need roughly 200 years or less to complete one orbit, long-period comets take more than 200 years, and single-apparition comets are not bound to the sun, on orbits that take them out of the solar system, according to NASA.
Yes, you can invest in both an IRA and a 401k (or a Roth 401k and a Roth IRA) at the same time, or any combination of those accounts. And in some cases, based on the fees in your 401k, an IRA might actually be a better place to invest your money.
The maximum contributions for either the Roth 401k or the traditional 401k are the same -- $16,500 in 2010. If you contribute to both a Roth 401k and traditional 401k, the sum of your contributions can't exceed that limit.If an employer offers a Roth 401k, most likely it would provide the same matching contributions as for a traditional 401k.There are really two main reasons to consider investing your current and future contributions in a Roth 401k.f you contribute to the traditional 401k: Since you aren't paying income taxes on the $10,000, you can invest the full amount. At 5 percent annual investment returns, your $10,000 will grow to $16,289 (if you're mathematically inclined, that's $10,000 times 1.05**10).