Movie about man who is teleported to Mars?

Question

I watched a movie around 8 years ago about a man who came across an old tomb, with some sort of relic that teleported him to Mars. He discovers that he is super strong, as the gravity doesn’t affect him as it does the other people on Mars. He then ends up back on Earth, discovering that he hadn’t moved for at least a week.

He also discovers he is being hunted down by ghost-like humanoids who have a goal to destroy the relic that allows him to travel between worlds and kill him. The movie is set around the 19th century, and seems to be told through a letter to his nephew. Unfortunately, I forgot the movie’s name. Does anyone have any idea what it is?

Answer 1

Might this be John Carter (2012)...?

In 1881, Edgar Rice Burroughs attends the funeral of his uncle, John Carter, a former American Civil War Confederate Army captain who died suddenly. Per Carter's instructions, the body is put in a tomb that can be unlocked only from the inside. His attorney gives Carter's personal journal for Burroughs to read, in the hope of finding clues explaining Carter's cause of death.

In a flashback to 1868 in the Arizona Territory, Union Colonel Powell arrests Carter. Powell, knowing about Carter's military background, seeks his help in fighting the Apache. Carter escapes his holding cell, but fails to get far with U.S. cavalry soldiers in close pursuit. After a run-in with a band of Apaches, Carter and a wounded Powell are chased until they take to hiding in a cave that turns out to be the object of Carter's earlier searching, the 'Spider Cave of Gold'. A Thern appears in the cave at that moment and, surprised by the two men, attacks them with a knife; Carter kills him but accidentally activates the Thern's powerful medallion, and is unwittingly transported to a ruined and dying planet, Barsoom. Because of his different bone density and the planet's low gravity, Carter is able to jump high and perform feats of incredible strength. He is captured by the Green Martian Tharks and their Jeddak Tars Tarkas.

Elsewhere on Barsoom, the Red Martian cities of Helium and Zodanga have been at war for a thousand years. Sab Than, Jeddak of Zodanga, armed with a special weapon obtained from the Thern leader Matai Shang, proposes a cease-fire and an end to the war by marrying the Princess of Helium, Dejah Thoris. The Princess escapes and is rescued by Carter. Carter, Dejah, and Tarkas' daughter Sola, embark on a quest to get to the end of a sacred river to find a way for Carter to get back home. They obtain information about the "ninth ray", a means of using infinite energy and also the key to understanding how the medallion works, but are attacked by Shang's minions, the Green Martians of Warhoon. After the attack, Carter is captured and taken back with Dejah while Sola is able to escape. The demoralized Dejah grudgingly agrees to marry Sab Than, then gives Carter his medallion and tells him to return to Earth. Carter decides to stay and is captured by Shang, who explains to him the purpose of Therns and how they manipulate the civilizations of different worlds to their doom, feeding off the planet's resources in the process. Carter is able to make an escape as he and Sola go back to the Tharks requesting their help. There they discover Tarkas has been overthrown by a ruthless brute, Tal Hajus. Tarkas, Carter and Sola are put on trial in a colosseum battle with two enormous vicious creatures, the four-armed Great White-Apes. After defeating them and killing Hajus, Carter becomes the leader of the Tharks.

Here's the scene where Carter actually gets transported:

Answer 2

John Carter.

The plot is very similar to what you describe, with the "nephew" being Edgar Rice Burroughs, who wrote the Carter of Mars novels.

Answer 3

As other answers have noted, this is clearly the 2012 movie John Carter.

To add a little more detail, for someone who's hazy on the property and character -- John Carter of Mars was a character created for a series of pulp stories and novels, starting in 1912, by writer Edgar Rice Burroughs. The film was released around the 100th anniversary of the character's creation (and Burroughs was prominently featured as a fictional character in the film).

So John Carter represents one of the foundational figures of 20th century pulp, fiction, and even superheroes. The idea of an Earthman who is relatively super-powered on a planet of lighter gravity was flipped about a quarter-century later, to conceive of what a person from a higher-gravity planet would be like on Earth -- i.e., the original concept for Superman (including specifically super-strength, speed, "leap tall buildings", etc.).

From Wikipedia:

Siegel and Shuster read pulp science-fiction and adventure magazines, and many stories featured characters with fantastical abilities such as telepathy, clairvoyance, and superhuman strength. One character in particular was John Carter of Mars from the novels by Edgar Rice Burroughs. John Carter is a human who is transported to Mars, where the lower gravity makes him stronger than the natives and allows him to leap great distances.

And more:

John Carter of Mars was a major influence on other science fiction/fantasy tales and characters through the 20th century, including Buck Rogers, Flash Gordon, Superman, Adam Strange, Dune, Warp!, Den, and Star Wars to name just a few.