In the 1982 blockbuster, E.T. the Extra–Terrestrial, E.T. is lured out of hiding using a trail of Reese’s Pieces.
But what would aliens really eat if they visited our planet?
According to Professor José Miguel Soriano del Castillo, a nutritionist from the University of Valencia, our planet would serve a ‘risky buffet’ for alien life.
Even if aliens have similar basic biology to us, there is no guarantee that foods that are safe for humans to eat would be compatible with their digestive systems.
Instead of snacking on human foods, this means aliens would be more likely to feast on the ‘raw materials’ found on Earth.
Writing in The Conversation, Professor del Castillo claims that aliens would sustain themselves on ‘water, nitrogen, phosphorus, iron, salts, lipids, microbial biomass or simple organic molecules’.
Unfortunately, this means E.T.’s Reese’s Pieces are off the cards.
However, Professor del Castillo suggests the classic UFO cow abduction might not be so far–fetched.
In the 1982 blockbuster, E.T. the Extra–Terrestrial, E.T. is lured out of hiding using a trail of Reese’s Pieces. But what would aliens really eat if they visited out planet?
While E.T.’s Reese’s Pieces are off the cards, the classic UFO cow abduction might not be so far–fetched (stock image)
Animals across our planet have developed a baffling array of unique digestive systems.
Cows, for example, are entirely dependent on the bacteria living in their stomachs to break down and digest cellulose in grass.
As Professor del Castillo points out, this means it is extremely difficult to say what an alien’s natural diet might look like.
However, there are a few basic facts common to all forms of life that can give us a basic understanding.
Scientists generally believe that life needs three things: a source of energy, a liquid in which chemical reactions can occur, and suitable chemical elements.
Since these components are readily available on Earth, there’s no reason that a visiting alien would need to go hungry.
A sufficiently advanced extraterrestrial might simply be able to hoover up organic matter from Earth and process it into something that suits their own digestive system.
However, Professor del Castillo warns that any interstellar tourists will need to be careful.
Alongside salts, fats and sugars that are essential to life, Earth’s environment is packed with potential toxins, pathogens, and allergens.
‘Earth’s food would not necessarily be edible for them,’ Professor del Castillo says.
‘Terrestrial protein might be of no use if their digestive systems used different amino acids. Our sugars might prove useless if their metabolism could not handle them.’
This is why sensible alien travellers would be well advised to sample some of the local produce, perhaps by abducting a cow or two, before eating anything from Earth.
In the distant future, if humans ever really did meet an extraterrestrial civilisation, Professor del Castillo says Earth would need to train alien nutritionists.
He says: ‘We would also need experts who could figure out what molecules these life forms tolerate, what energy they require, what poisons them, what microorganisms they carry, and what resources they could use without destroying the planet’s ecosystems.’
While much of that information will depend on the specific organism, scientists can already start to estimate how much energy these aliens might need to consume.
In land animals, the amount of calories something needs to consume increases with its size, but not proportionally.
If UFOs really have visited Earth, our planet’s biology would make eating human or animal food quite dangerous. Instead, aliens would need to feed themselves with the raw materials found on this planet. Pictured: An image of a UAP submitted by the FB to the All–domain Anomaly Resolution Office
That means an elephant needs more fuel than a mouse, but uses fewer calories per gram of body mass.
An alien weighing 70 kilograms would require around 1,700 kcal per day, while a massive 150–kilogram extraterrestrial would need over 3,000 kcal just to sustain itself without moving around a lot.
That is just the very basic amount needed to sustain life, and doesn’t include all the extra energy that organisms need to move, think, operate machinery, fly a UFO, or abduct farmers.
However, an even stranger possibility is that alien life won’t need any food at all.
Many scientists believe our first visit from an extraterrestrial civilisation won’t be in the form of a biological visitor, but a robotic probe.
There is also the possibility that truly advanced aliens might have transcended their fleshy forms to become a ‘post–biological entity’ with a synthetic body.
Professor del Castillo says: ‘In this case, “food” would no longer consist of proteins, fats or carbohydrates, but electricity, heat, chemical fuel or nuclear energy.
‘An alien robot wouldn’t eat rice or pasta, it would simply need to recharge its batteries.’
WHAT IS THE FERMI PARADOX?
The Fermi Paradox questions why, given the estimated 200-400 billion stars and at least 100 billion planets in our galaxy, there have been no signs of alien life.
The contradiction is named after its creator, Italian physicist Enrico Fermi.
He first posed the question back in 1950.
Fermi believed it was too extraordinary that a single extra-terrestrial signal or engineering project has yet to be detected in the universe — despite its immense vastness.
Fermi concluded there must a barrier that limits the rise of intelligent, self-aware, technologically advanced space-colonising civilisations.
This barrier is sometimes referred to as the ‘Great Filter’.
Italian physicist Enrico Fermi devised the so-called Fermi Paradox in the 1950s, which explores why there is no sign of alien life, despite the 100 billion planets in our galaxy
If the main obstacle preventing the colonisation of other planets is not in our past, then the barrier that will stop humanity’s prospects of reaching other worlds must lie in our future, scientists have theorised.
Professor Brian Cox believes the advances in science and engineering required by a civilisation to start conquering the stars will ultimately lead to its destruction.
He said: ‘One solution to the Fermi Paradox is that it is not possible to run a world that has the power to destroy itself.
‘It may be that the growth of science and engineering inevitably outstrips the development of political expertise, leading to disaster.’
Other possible explanations for the Fermi Paradox include that intelligent alien species are out there, but lack the necessary technology to communicate with Earth.
Some believe that the distances between intelligent civilisations are too great to allow any kind of two-way communication.
If two worlds are separated by several thousand light years, it’s possible that one or both civilisations would become extinct before a dialogue can be established.
The so-called Zoo hypothesis claims intelligent alien life is out there, but deliberately avoids any contact with life on Earth to allow its natural evolution.
