Node.js/express: curl: (52) Empty reply from server with space in request not encoded

Node.js/express: curl: (52) Empty reply from server with space in request
not encoded

// Load the http module to create an http server.
var http = require('http');
// Configure our HTTP server to respond with Hello World to all requests.
var server = http.createServer(function (request, response) {
response.writeHead(200, {"Content-Type": "text/plain"});
response.end("Hello World\n");
});
// Listen on port 8000, IP defaults to 127.0.0.1
server.listen(8000);
// Put a friendly message on the terminal
console.log("Server running at http://127.0.0.1:8000/");
curl "http://127.0.0.1:8000/"
Hello World
curl "http://127.0.0.1:8000/x y"
curl: (52) Empty reply from server
curl "http://127.0.0.1:8000/x"
Hello World
Can you please explain the why I get curl 52???