I'm watching a movie trailer for "Interstellar." Large cornfields, distant mountains from far-off worlds. But I'm in a movie theater, watching these vistas. All around me are empty seats. The projector, far behind me, flickers. I reach for my armrest. I find my backpack. A bump, a jostle. A station announcement.

Actually, no, I'm not in a movie theater, I'm on a train. I take off the helmet. I'm at Penn Station. Why watch a movie trailer in a virtual movie theater rather than on my phone? I'm not sure I can answer that, but the experience was more profound than I could have imagined.

I've been in an aquarium on the sofa, someone's quiet apartment listening to music while lying in bed. Dare I explore the solar system while sitting on a public park bench?

This is mobile virtual reality: the Samsung Gear VR. It's a headset, like the Oculus Rift ; in fact, it's made in partnership with Oculus. But unlike Facebook's fabled virtual-reality goggles, you can buy the Gear VR now (in the US, at least) for just $199. It runs a handful of demo apps, experiences, panoramic photos and videos and games. But it only works with one phone: the Samsung Galaxy Note 4 , which -- when snapped into the headset -- acts as the display.

And, in the five years I've worked at CNET, I'm not sure I've experienced anything more magical.

Update, March 2017: There's a new and improved Gear VR for 2017, one compatible with more phones and more games. You may want that one instead -- or at least its new controller to go with this headset.

Original review continues:

Sarah Tew/CNET

Shock of the new: How the Gear VR works

At some point in the history of cinema, back in its dawn, there's that story of people screaming and ducking during a screening of an early Lumiere film of an oncoming train ("Train Pulling Into a Station," 1896). Maybe you saw the scene in "Hugo." Virtual reality is that type of experience, now. For the uninitiated, it can be jaw-dropping. Jarring. Off-putting. Addicting. With the Oculus Rift, Sony's Project Morpheus (I'll leave off Google's Cardboard and Project Tango VR, because they're far less effective, for now), you're sucked into a 3D world that ends up being a lot more absorbing and immersive than you expect. You're in the cockpit of a starship. You're battling a dragon. You can look all around you. It's there, in your face.

I never thought I'd see a technology that had that same effect as early Lumiere films, but VR is definitely it.

Samsung's Gear VR uses the same effective optical technology as those Oculus and Morpheus headsets: it's like a plastic set of ski goggles, with a front bracket that holds the Note 4 in place. It slots in via a Micro-USB plug, snaps on, and becomes the Gear VR's screen. Elastic Velcro straps on the sides and top keep the goggles in place. A proximity sensor turns the headset on the moment it's put on your head. Two large, curved lenses melt the display's split screens into spherically immersive panoramic video and 3D experiences. You can adjust focus with a top dial. The Gear VR isn't meant to work with glasses. I have a -9 prescription, and the Gear VR just barely worked by spinning the focus dial all the way to the end. Everybody else who tried it -- many of them who wear glasses -- had no problem.

Sarah Tew/CNET

The Gear VR takes the idea of VR and turns it mobile. There's no PC or game console to plug into: your phone (the Note 4, that is) does everything. The included kit you get for $199 -- the "Innovator Edition" -- includes the headset, a 16GB microSD card loaded with content plus an SD card adapter for loading on your own videos, and a zippered carrying case. The Gear VR is bulky, but takes up as much space in a backpack as a large pair of over-ear headphones.

Setting up the Gear VR took about 40 minutes: downloading a software update on my loaner AT&T Note 4, loading an Oculus app and creating an Oculus account. After popping in the Note 4 to the headset, a voice told me to pop the phone back out and continue the setup: a store offers more than a dozen apps and experiences, all of which are currently free. I downloaded them all.

Yes, wearing the Gear VR on your head will inspire taunts from friends, curious looks, maybe mockery. But when I let those same people actually try it on for a while, they ended up quieting down.

Scott Stein/CNET

Lenses for your phone

Google Cardboard, the do-it-yourself VR kit for phones, showed how the magic behind VR isn't really contained in the headset so much as the software. That's true -- the Gear VR feels mostly like a fancy pair of goggles for the Note. It's basically a USB-connected mouse with lenses: it adds the built-in touchpad, back button, volume controls (all on the side of the headset), and of course the lenses. Multiple motion-sensitive head controls: accelerometer, gyrometer and geomagnetic (compass) sensors are on board, along with a facial proximity sensor. That's how you interact with the Gear VR: no haptic gloves, no arm-scanning cameras. Not yet, at least. You can also pair a Bluetooth controller for some games (Samsung makes a gamepad, or you can use another that's Android-compatible.)

The Note 4 was one of the best phablets of 2014, and it provides a good foundation for the Gear. The phone's 2,560x1,440-pixel, 5.7-inch OLED display, a fantastically pixel-dense screen, ends up feeling more like a minimal baseline when blown up across a magnified 96-degree field of view and split across two separate eyes.