This week. New shape: bit.ly/1jHVFID Y chromosome: bit.ly/1hrLASQ Chernobyl: bit.ly/1tOdLR8 Coldest star: bit.ly/1fgit6q Pterodactyloid: bit.ly/1hwaZuO Aging: b This week New shape: bit ly/1jHVFID Y chromosome: ly/1hrLASQ Chernobyl: ly/1tOdLR8 Coldest star: ly/1fgit6q Pterodactyloid: ly/1hwaZuO Aging: b