I wrote a series of posts back in May 2009 that was supposed to be a larger project. I only wrote the intro, three chapters, and a semi-serious essay on the ethics of time travel. Going forward in time was far more difficult.
Going backward in time seems simple enough, go back in time, see stuff, take pictures, buy ancient Egyptian souvenirs and return to the present. Well, hold it right there, Millennium Man (or woman), it's not that easy. As with any trip it helps to have a plan before one leaves. First and foremost, choosing a time period is a good place to start. Most people wouldn't wait until the last minute to plan a conventional trip, why do so for time travel? It would also make sense to find out if anything of interest took place around the starting location. Starting location is very important for many other reasons, as well.
Location is everything in time travel for numerous reasons. Most time machines only travel through the time dimension, but getting one equipped to travel in the space dimension at the same time is possible. These machines are usually expensive and are still wrought with problems that can be deadly. The best idea is to find a portable model and take it to wherever seems interesting. If a portable time machine is out of the question, check out what happened around the current area and use that as a starting point. This helps to make a vacation much more affordable. If the time machine was built in a sixth floor apartment, there may be an issue if traveling back further than the age of the building. One may also want to research what was on the starting location in the past will also be necessary. Many time travelers have expressed a lack of desire to be embedded in a tree 600 years prior. Taking measurements of the room one is leaving from and noting the positions of specific items in the room is also good planning. Locking the door to the room will prevent unwanted results from occurring, like accidently smooshing the family dog, cat or curious child. Following these guidelines will help make it a safer trip, but there plenty of other things to consider. It's helpful to consider the weather and atmosphere of the past.
When traveling in time, different eras may have some different weather to worry about. There is, of course, the ice age which is quite cold and does require a warm jacket. The very first days of the earth were quite warm, so short, a tank-top and flip-flops are definitely recommended. The atmosphere is also a factor to consider since the days of the dinosaurs saw high levels of ammonia which may make a bit difficult to breathe. The smart time traveler may want to pack some oxygen for the trip. Packing the right clothes doesn't stop at the weather, they may also keep one alive in the past.
Not only are functional clothes needed when going back in time, but clothing suitable for the era to which one is traveling. Looking like an out of place tourist may be fine for Florida in winter, but the Civil War in the summer could be fatal. It would be wise to brush up on fashion for the specific time, after all, dressing like a Yankee while in Georgia is a sure way to make it a very quick trip. This works in the opposite direction, too. Clothes can definitely save a life in more ways than one, but it also helps to brush up on the language and customs of the era one is visiting.
Things have always changed throughout history, like language and vocabulary. It would be very wise to study the changes in meanings of words between then and now as many words do not yet exist in the past and many others did not mean the same thing as they do now. It is incredibly useful if one knows the customs of the day that he/she is visiting. It pays to not insult the people of the past and possibly end up either jailed or executed. Leave all electronic devices, computers, mp3 players, cell phones, in the present. Cell phones will not work, even in the recent past of the 1980's and other electronics may be seen as tools of the devil in colonial America. This could result in the holder being accused of witchcraft. Information on what happens to witches can be found in The Crucible by Arthur Miller. It helps to know the culture of the period one is going to, however, all of this preparation may just be for naught if the word isn't there.
There are limitations to time traveling backwards when it comes to the era. The earth is about 4.5 billion years old and, frankly, the first billion or so years were pretty boring for the average time tourist. The first 10 billion years of the universe were quite volatile and unsafe and it is not recommended according to the TTA (Time Travel Association). Stay safe and keep the time travel to a point when the planet is actually there. Luckily, most time machines are equipped with safeties to keep from going back too far in time and prevent "Big Bangin'" as it is referred to by teenagers.
It is always helpful to have a plan when it comes to time travel. Keep in mind the starting location and the history contained there, it could make for an unexpectedly pleasant vacation. Remember to start off at ground level and find out what on that particular spot to prevent any catastrophic events. The clothes make the trip, dress for warmth, safety and survival (also, not looking like a tourist helps). Making sure that the planet is actually present helps make for an enjoyable trip since 98% of time travelers find that floating in an empty void does not make for the ideal vacation. Now it's time to buckle up and go back in time.