You can only go forward through a stargate, so you should hide and camp near it. When you hear noise, either Earth is dialing you to send someone that dial back, or the stargate is programmed to dial automatically within a year.

In the mean time, you'd eat, protect yourself, farm and gather resources.

You should stop any activity that requires you to move away when you realize your hair has grown about one of your finger's length, given it should grow about 15 centimeters per year (so pick your finger wisely). By then, you'd wait for the stargate to open, consuming what you could gather.

For instance, rhythm or internal clock is totally susceptible (you can't really count the time it takes for a rock to fall of a height that is a multiple of your height), heartbeat depends on relaxation (or lack of it) and tiredness, etc.

• Your hair grows about 15 centimeters or 6 inches per year

• Your finger nails grow about 3 millimeters per month

  If you have grown finger nails, you can bite your finger nails up until the white part is gone, and roughly estimate the white part as it grows back

• If you're a man and you've shaved your beard recently, you should know about how many days it takes to grow e.g. a 1 finger girth of beard

  Likewise if you're a woman, but replace the 1 finger of beard with e.g. 1 or 2 millimeters of leg hair, or visually, whatever you usually let grow

• If you somehow know how much time you take to relieve a full bladder, you can drink all the local water you can and go for it

  It's equally good to know how much time it takes until you feel the need to relieve your bladder since you filled an empty stomach with water

  If you can't find potable water, measuring the passage of time is the least of your worries

In case you can think of things that take at most one hour, you could also build a big hourglass: a base and a funnel made of tree cork, or leaves and sticks, or a cone-rolled sheet of malleable plastic or metal, filled with sand or dust.

Once such a process is done (e.g. holding your breath), you'd remove the rest of the sand, and perhaps a handful more (see last paragraph).

Do this until you get something above 4 hours worth of sand; remember, you'll always double the sand, so be careful not to overweight.

As a final hint, always make your estimates below, because you'd rather be early than late for the stargate opening.

You can only go forward through a stargate, so you should hide and camp near it. When you hear noise, either Earth is dialing you to send someone that dials back, or the stargate is programmed to dial Earth automatically within a year.

In the mean time, you'd eat, protect yourself (probably underground), farm and gather resources.

You should stop any activity that requires you to move away when you realize your hair has grown about one of your finger's length, given it should grow about 15 centimeters per year (so pick your finger wisely). By then, you'd wait for the stargate to open, consuming what you have gathered.

For instance, rhythm or internal clock is very susceptible to failure, you can't really count the time it takes for a rock to fall of a multiple of your height, heartbeat depends on effort, stress and tiredness, etc.

• Your hair grows about 15 centimeters or 6 inches per year

• Your finger nails grow about 3 millimeters per month

  If you have grown finger nails, you can bite your finger nails up until the white part is gone, and roughly estimate the length of the regrown white part

• If you're a man and you've shaved your beard recently, you should know about how many days it takes to grow e.g. a 1 finger girth of beard

  Likewise if you're a woman, but replace the 1 finger of beard with e.g. 1 or 2 millimeters of leg hair, or visually, whatever you usually let grow

• If you somehow know how much time you take to relieve a full bladder, you can drink all the local water you can and go for it

  It's equally good to know how much time it takes until you feel the need to relieve your bladder since you filled an empty stomach with water

  If you can't find potable water, measuring the passage of time is the least of your worries

In case you can think of other things that take a few minutes and at most one hour with relatively good reliability, you could also build a big hourglass: a base and a funnel made of tree cork, or leaves and sticks, or a cone-rolled sheet of malleable plastic or metal, filled with sand or dust.

Once the timed task is done, you'd remove the rest of the sand, and perhaps a handful more (see last paragraph).

Do this until you get something above 8 hours worth of sand; remember, you'll always double the sand, so be careful not to overweight. You'll have to rotate or refill the hourglass all the time, so you better sleep well right after a rotation.

Otherwise, stick to the longer term estimates.

As a final hint, always make your estimates below, because you'd rather be early than late for the stargate opening. And keep calm, as that will allow your body to function with less inhibitions, thus making your early time estimates more accurate (yes, because the Earth year doesn't wait for you to find a good estimate, you must take into account the time you spend from the first moment the stargate is closed).