Of course we can! The answer is no, there are no aliens from other planets. This is not the answer you wanted, but if you really understood how far a light year is then you would know the very nearest star is 4 light years. Another candidate is 40 light years.
No one can achieve or even approach the speed of light. To go 4 light years at max speed, and then slow down once you got there, would take no less than 150 years each direction.
To go to a more likely candidate Trappist 1 at 40 light years would take 1,500 years each way, whether you were an alien from there or from Earth.
However the chances space dwelling entities live so close is unlikely.
The more likely distances are thousands or millions of light years away.