Immortality. In movies, kings are always searching for the secret to immortality. But is immortality really a good thing? To a ten-year-old boy, one year is the same as 10% of his life. To his forty-year-old mother, one year is merely 2.5% of her life. The same year, 365 days, can feel differently to different people. If we live until we're 82, that's about 30,000 days. If this boy lives for 30,000 years, a year to him could feel like a day. And if this boy's emotions sustain through the potential boredom of living for millions of years, he might become extremely lonely and sad, knowing he has and always will outlive everyone he has ever loved. But what if everyone were immortal? Well, first off, Earth is only so big. So, where would we all live? (Grunts) "Excuse me!" "That's my face!" "Stop it!" "Pardon me." "Tight in here!" Do you remember what you did last year or when you were five? How much of your past have you forgotten? If you have trouble remembering what you did when you were five, how will you remember what happened if you were alive a thousand years ago? A million years ago? We don't remember every single detail of our past because our brains have a limited capacity and we replace useless memories, like middle school locker combinations, with relevant information. If this immortal boy finds a companion to fall in love with once every hundred years, he would have ten thousand girlfriends in a million years. And how many of those ten thousand girls' names will he be able to remember? This changes what a meaningful relationship means, doesn't it? Another tricky thing about immortality: Human beings have not always looked the same. This can be explained by Darwin's theory of evolution. For instance, if women find taller men more attractive, then more tall men would mate and have children, putting more tall genes in the gene pool. That means, in the next generation, more children will have the genes to be taller. Repeat that process for a million years and the average height will be a lot taller than the average height today, assuming there's no natural disaster that wipes out all the tall people. Our ancestors were short, hairy apes. We still have body hair, but we don't look like apes any more. If you're the only person who is immortal, while everyone else keeps evolving, generation after generation, you will eventually look quite different than the people who surround you. "Hi, how you doing?" If one of our ancestors, apes, is still alive today, how many people will make friends with it instead of calling the Museum of Natural History? And one more physical consideration for immortality: Scars. After all, immortality doesn't automatically translate to invincibility, it just means you cannot die. But it doesn't guarantee what condition you'll be alive in. Look at your body and count how many scars you have. If you have made this many permanent scars within your life, imagine how much damage you would have if you were one thousand years old! Now, there are approximately 185,000 amputation-related hospital discharges every year in the U.S. These injuries are due to accidents or illnesses. Certainly the percentage is low comparing to the total population if you only live for a hundred years. However, if you've been alive for over one million years, the odds of still having all your limbs are pretty slim. What about little accessories, like your eyes, your nose, your ears, fingers or toes? What about your teeth? What are the odds of you keeping your dental health for a hundred years? A thousand years? One million years? You might end up looking like a horribly scuffed-up Mr. Potato Head with missing pieces and dentures. So, are you sure you want to live forever? Now, which superpower physics lesson will you explore next? Shifting body size and content, super speed, flight, super strength, immortality, and -- invisibility.
Besmrtnost. U filmovima, kraljevi uvek traže tajnu besmrtnosti. Ali, da li je besmrtnost stvarno dobra? Za desetogodišnjaka, jedna godina je 10% njegovog života. Za njegovu 40 godina staru majku, jedna godina je tek 2,5% njenog života. Ista godina od 365 dana može delovati drugačije različitim ljudima. Ako živimo 82 godine, to je oko 30.000 dana. Ako bi ovaj dečak živeo 30.000 godina, godina bi mogla da mu izgleda kao dan. I ako uspe da se odupre potencijalnoj dosadi tokom života dugog milionima godina, mogao bi da postane izuzetno tužan i usamljen, zbog saznanja da će uvek nadživeti sve one koje je ikada voleo. Ali, šta ako bi svi bili besmrtni? Pa, pre svega, Zemlja je ovoliko velika. Dakle, gde bismo svi mi živeli? "Izvinite!" "To je moje lice!" "Prestani!" "Oprostite." "Ovde je tesno!" Sećate li se šta ste radili prošle godine? A, šta kada ste imali 5 godina? Koliko svoje prošlosti ste zaboravili? Ako vam je teško da se setite šta ste radili sa 5 godina, kako ćete se sećati šta se događalo pre 1.000 godina? Pre milion godina? Ne pamtimo svaki delić naše prošlosti jer naš mozak ima ograničen kapacitet. Zamenjujemo nevažna sećanja, poput šifre na ormariću u osnovnoj školi, sa bitnim informacijama. Ako ovaj besmrtni dečak nalazi devojke u koje bi se zaljubljivao na svakih 100 godina, ima bi 10.000 devojaka tokom milion godina. I koliko bi imena, od ovih 10.000 devojaka, uopšte mogao da se seti? Ovo menja značenje ozbiljne veze, zar ne? Još jedna nezgodna stvar u vezi sa besmrtnošću: ljudi nisu uvek izgledali isto. Darvinova teorija evolucije ovo objašnjava. Na primer, ako su visoki muškarci ženama privlačniji, onda će se više visokih muškaraca oženiti i imati decu, dodajuči više "visokih gena" u bazu gena. To znači da će u sledećoj generaciji, više dece imati genetski potencijal da budu visoki. Ponavljajte taj proces milion godina i prosečna visina će biti znatno veća od prosečne visine danas, pod pretpostavkom da nema prirodnih katastrofa koje bi pokosile sve visoke ljude. Naši preci su bili niski, dlakavi majmuni. Mi još uvek imamo dlake na telu, ali ne izgledamo više kao majmuni. Ako ste vi jedina besmrtna osoba, dok svi ostali evoluiraju generaciju za generacijom, na kraju ćete izgledati prilično drugačije od ljudi koji vas okružuju. "Hej, gde si?" Da je neki od naših predaka majmuna živ danas, koliko bi se ljudi družilo sa njim, a koliko bi ga prijavljivalo Prirodnjačkom muzeju? I još jedan fizički aspekt besmrtnosti: ožiljci. Jer, besmrtnost ne znači istovremeno i nepovredivost, već samo to da ne možete umreti. Ne garantuje vam se u kom stanju ćete biti živi. Dakle, pogledajte svoje telo sada i prebrojte koliko ožiljaka imate. Ako ste napravili toliko trajnih ožiljaka tokom svog života zamislite koliko bi vam koža bila oštećena da ste stari 1.000 godina! Svake godine se uradi otprilike oko 185.000 amputacija u SAD. Ovakve povrede su posledica nesreća ili bolesti. Naravno, procenat je mali u odnosu na celu populaciju ako biste živeli 100 godina. Ipak, ako biste živeli preko milion godina, šanse da biste imali sve udove su prililno male. I, šta je sa malim dodacima, poput očiju, nosa, ušiju, prstiju? Šta bi se događalo sa zubima? Koje su šanse da biste održali zdrave zube tokom 100 godina? 1.000 godina? Milion godina? Možda biste završili izgledajući kao strašno pohabani Teletabis, sa delovima koji nedostaju i protezama. Dakle, jeste li sigurni da želite da živite zauvek? Sada, koju ćeš sledeću lekciju o super-moćima da istražiš? Promena veličine tela, super-brzina, letenje, super-snaga, besmrtnost i