Most sightings are the result of luck, the right place at the right time. There is no pattern or any way to predict when UFOs appear.
The Passport 8500 X50 can detect lasr and radar signals.
freak for got it
Electrical signals
they use telescopes that find certain wavelengths
rod and cone cells
The medulla in the brain is where the cardiac centre is. From here it receives signals from the chemoreceptors, these receptors detect chemical. They detect the amount of carbon dioxide in the blood.
A wave meter tube is a tubular device used to detect wave signals from electronic devices. It can be used to detect microwaves, and waves emitted from televisions.
They might be visible because if people have not seen them then why they would name as Unidentified Flying Objects. The UFO's disturb your radio signals and satellite if they exist.
If you are airborne, the UFO will not "beam you up". Similarly, if you are flying (super power or jetpack), the guards cannot detect you on the Race to Witch Mountain mini-game. On Early Poptropica island, the crashed airplane in the clouds keeps you suspended, as do the monorail exhausts on Time Tangled Island. The UFO will not be able to "lock on to you" and will hover about.
The real life cheat code to spawn a UFO is to stand still for two minutes, turn to your left, do a 180 degree turn, crouch, then roll left. A UFO should spawn somewhere nearby. It is recommended you do this in a field to avoid the spawning craft merging with any obstructions. Unfortunately the craft will be intangible making it difficult to pilot. It will also be invisible. Additionally, it will emit no carbon radiation, and will fail to interact with any present carbon radiation whatsoever making it virtually impossible to detect by any means available. The only known means to detect this radiation will be with the UFO's sensors which will be, unfortunately, also intangible and invisible.
Barometer
it is a type of behaviour in which with help of flagella,flagellate bacteria can detect and move in response to chemical signals