1. I looked up the phase diagram of water. If the mass is 10 times the earth, their athmospheric pressure might be one hundred times of ours. At that pressure, water boils at about 300°C. If ambient temperature is about 200°C then their chemistry would be completely incompatible with ours. And with hydrogen athmosphere anyway.<p>2. Re the Dark Forest hypothesis: maybe. They will discover our radio in about 60 years (assuming that our broadcasting only started to be strong enough to notice 60 years ago). Then they might assemble something like a robotic attack army and send it over after, let's say 10 years. And if they are capable to send something half the light speed, then we might encounter our demise after 240 years more. So we still can enjoy our Earth 300 years or more if we don't destroy our livelyhood basis on Earth ourselves before that. Perhaps we could retaliate and send something back, but probably the odds are bad.<p>3. However there's the Loud Aliens And We Are Early hypothesis as well: maybe. There's life on that planet but not as advanced as ours. We will find more signs of life the next decades in that case. Then maybe send several robot probes. Contact could be possible after: 30 years of building the first probe, sending it over: 600 years (assuming we can reach 20% of light speed) and first reporting back 120 years, in total 750 years.<p>Caveat emptor: This is all speculation.