Not getting correct uptime in messages file

The following notice I am getting in /var/adm/messages file

Dec  9 06:17:24 hostname lw8: [ID 925147 kern.notice] Main, up 476 days 04:42:23, Memory 9,742,808
Dec  9 10:17:25 hostname lw8: [ID 433305 kern.notice] Main, up 476 days 08:42:23, Memory 10,179,864

But my actual uptime is ::

 11:55am  up 25 day(s), 10:38,  3 users,  load average: 1.72, 1.81, 1.87

Why is that ??

What Operating System and version do you have?

There are certainly known issues in Open Solaris if your Real Time Clock has a flat battery (or was wrong at startup) and the clock was subsequently corrected manually or corrected with NTP.
i.e. The clock changed after the kernel loaded but before System Accounting made a timestamp in the "utmp" file (which is used by the "uptime" command).

Thanks methyl...

Operating system is:

SunOS upeminsat1 5.10 Generic_138888-01 sun4u sparc SUNW,Netra-T12

Are you able to check your clock (that's the one on the system board)?

I am sorry if I am Silly.. But How can I check It?

Cold start the computer. The clock setting bit should be before unix loads. Check your hardware manual.