Backyard Observatory

Here's How Far Mars Is from Earth & How Long It Takes to Get There

Also, the answer to a couple of other frequently-asked questions about Mars.

how far away is Mars
Image courtesy of NASA/JPL-Caltech

Mars has piqued our curiosity more than any other planet. Whether we're talking about science or science-fiction, there's something alluring about the red planet that has kept it in our collective imagination.

That hasn't abated in recent years as more probes and rovers make the long journey to the fourth planet from the sun. Understandably, it's often hard to contextualize some of the details about the scale of the universe when Mars is in the news. How big is Mars compared to Earth? How far away is Mars? The enormity of the distances we talk about in space can be hard to imagine, even with something as relatively close and familiar as Mars.

That can even be the case when you're stargazing and see the familiar red glow of Mars. Maybe next time you're watching the red planet get cozy with the moon or shine brightly among the stars, you'll be able to remember a little bit more about our celestial neighbor.

How far is Mars from Earth?

The answer to this question varies quite a bit. Both planets are in orbit around the sun and a single year for each planet (one complete orbit around the sun) takes a different amount of time. A year on Mars lasts for about 687 Earth days or 669 sols (Mars days). The distance between Mars and Earth will vary greatly depending on where each planet is in its orbit. 

At its closest approach to Earth in 2020, Mars was about 38.6 million miles (62.07 million kilometers) from Earth, per NASA. That's about the exact same distance it'll be from Earth when the planets have another close approach in 2022. (Those happen roughly once every two years.)

As Space.com explains, the closest the two planets could theoretically get is 33.9 million miles. Though, the closest we've seen the two was 34.8 million miles in August 2003. When the planets are as far away from each other as possible, they could be as many as 250 million miles apart. For reference, on average, Earth is about 93 million miles away from the sun. 

How long does it take to get to Mars?

There are a whole lot of factors at play, like the distance and how you think you're getting there. (A rocket you made up or on the path which NASA has sent rovers?) Of particular relevance, Perseverance is about to complete this trip. It took the rover about seven months to get from Earth to Mars.

Perseverance launched on July 30, 2020, and is slated to arrive at the red planet on February 18, 2021. That's 204 days, which is less than the 253 days it took curiosity to get to Mars in 2012. Though, that's not the fastest, either. Mariner spacecraft 6, 7, and 9 all got there in 168 days or less, per Space.com.

Image courtesy of NASA/JPL-Caltech

How big is Mars compared to Earth?

As NASA notes in the handy diagrams above, Mars is 4,220 miles in diameter, which pales in comparison to Earth's 7,926 miles. To translate that into volume—and the way we often compare the Earth's size to the sun—it would take about six Mars to fill the volume of our planet. 

That makes Mars the second-smallest planet in the solar system. It's only larger than Mercury, which has a diameter of about 3,032 miles, per NASA

Image courtesy of NASA/JPL-Caltech

When will NASA send astronauts to Mars?

The short answer is that we don't know, but it's not going to be soon. NASA's Artemis program is working on making this happen right now. Sending humans to Mars, however, is a much larger challenge than putting a rover on the Martian surface. Though, as NASA notes, "exploration of the moon and Mars is intertwined."

The Artemis program aims to send the first woman and next man—a phrase frequently used by NASA—to the lunar surface by 2024. That's not Mars, but it is the first step in the "moon to Mars" mission. The agency wants to establish "sustainable exploration by the end of the decade," using what it learns in the process to make the push toward getting astronauts on Mars. 

The current Artemis program plan is sprawling. It involves establishing a "permanent human presence" on the moon and laying "the foundation for private companies to build a lunar economy," according to NASA. So, there's no answer, but the first steps are being taken. Exploration of the moon in the Artemis program will look at the equipment that can be used to get to Mars like habitats, life support systems, and "technologies and practices that could help us build self-sustaining outposts" on another planet. In fact, that process has already started. The Perseverance rover is carrying potential spacesuit material for astronauts who make the journey in order to test its resilience in the Martian atmosphere.

Ready to go stargazing?

Here are all the best stargazing events that you can get out and see this month or you could stay in a stream the northern lights from home. If you're just getting started, check out our guide to astronomy for beginners, the best meteor showers of 2021, or easy stargazing road trips from big US cities

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Dustin Nelson is a Senior Staff Writer at Thrillist. Follow Dustin Nelson on Twitter.
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