Hear the first sounds from the 2015 Formula 1 contenders.

Sebastian Vettel in the Ferrari SF15-T (photo: Scuderia Ferrari)

First day of winter tests at Jerez in Spain today.  Cars still sound weird,  sizzling and popping on their way out the pit but laps times are already faster than last year at the same venue.

Just testing of course but, straight out of the box, Mercedes put together over twice as many laps as the nearest competitor, Williams.

At the bottom of the milage order is Mclaren-Honda. Clearly from the video, there are engine issues to sort out yet before Alonso can put down a time.

Lotus never showed up.

Toto Wolff on crutches again but Mercedes was solid

Perhaps the surprise of the morning is Ferrari: Vettel's 1:22.690  on the harder tire, despite turning just 31 laps must be encouraging for the team.

Every team will need encouragement though with Mercedes ominously pounding away at long runs without reliability issues from day one does not bode well for its rivals.

As of this writing there is over an hour to go in today's session so it's possible Mercedes will decide to let Rosberg do a late flyer

Laps completed with about an hour to go:

Mercedes: 136
Williams: 51
Toro Rosso: 41
Sauber: 40
Red Bull: 31
Ferrari: 31
Mclaren: 6

Lap times.

1 Sebastian Vettel   Ferrari 1m22.690s
2 Nico Rosberg       Mercedes 1m23.106s +0.148
3 Daniel Ricciardo  Red Bull 1m23.338s +0.380
4 Valtteri Bottas      Williams 1m23.906s +0.948
5 Marcus Ericsson  Sauber 1m24.383s +1.425
6 Carlos Sainz Jr     Toro Rosso 1m25.327s +2.369
7 Fernando Alonso McLaren 1m40.738s +17.780