1..5|.{process{$_ * 2}} # what is this exactly?

Question

What is the difference between these two PowerShell statements?  The first used the ForEach-Object cmdlet in a way that I'm used to by now, but the second is something new to me.
<#c:#> 1..5|ForEach-Object{$_ * 2}
2
4
6
8
10
<#c:#> 1..5|.{process{$_ * 2}}
2
4
6
8
10

Answer 1

>>   1..5|.{process{$_ * 2}} # what is this exactly?   <<
This is an array being piped to a scriptblock (defined in loco).
The '.' can be substituted by '&'.
Another way:
PS Q:\> $sb={process{$_ * 2}}
PS Q:\> 1..5 | &$sb
2
4
6
8
10
Another interesting result:
PS Q:\> 1..5|&{$input*2}
1
2
3
4
5
1
2
3
4
5
I have no time to waste.
[. is a call operator (& alternative) in PowerShell] - I have already mentioned it. Let's OP come back. 
Note: $inout is an ENUMERATOR which gives access to the pipeline we have.
Regards Chen V [MCTS SharePoint 2010]