We don't have anybody like Michael Crichton anymore. People will tell you to try Brown (Dan) if you say that too loudly, but it is true.
Sure you can read Brown, but only if you consider dumbed-down pseudo-science and poorly researched historical conspiracies presented as fact 'the exact same', then maybe.
I suppose Dan Brown is Michael Crichton for the masses; he draws normally uninterested readers in with socially controversial topics and makes them feel like they have some ridiculous new insight into them. Dan Brown writes basically the exact same kind of books Michael Crichton does.
The big difference is that with Dan Brown books he throws in cliffhangers at the end of every chapter.
I have yet to find any other author that matches Michael Crichton's dedication to proper research for a novel nor one that understands the topics he writes about as well as he did.
Read some of his older books (Terminal Man, Congo) and nothing in them seems all the extraordinary because today all of that technology is commonplace. Apply that to his newer books (Prey, Jurassic Park, etc. even aspects of Timeline) and consider that he might able to give a very real view of the future and problems we might want to contemplate before it's too late.
If we're able to produce enough anti-matter to blow up the Vatican (or do anything useful), measure the weight of someone's soul, or even create a practical rifle that can compress/heat snow/sand into ice/glass bullets in the next 40 years, I'll come back here for my public shaming.
As far as I know, there's currently no replacement for Michael Crichton.