"Did Mars once look more like Earth?" NASA asked Wednesday night. The short answer: maybe.

Billions of years ago, Mars had a thick atmosphere and magnetic field not dissimilar to Earth's. But over time, perhaps 4.6 billion years ago, Mars lost its magnetic field and solar winds began to whip away the oxygen- and nitrogen-rich atmosphere.

This process releases charged ions out into space, NASA said Thursday, as scientists working on the agency's MAVEN spacecraft mission. Today, Mars' atmosphere is just 1 percent as dense as Earth's at sea level,in advance of the announcement.

“For the first time we have measurements that tell us not only the [atmosphere] escape rates lost to space, but the processes that control it,” MAVEN lead investigator Bruce Jakosky, of the Laboratory of Atmospheric and Space Physics (LASP) at the University of Colorado, Boulder, said in a press conference Thursday. “Most of the stripping of [atmosphere by] the solar winds … took place earlier when the sun was more active, when the winds were more intense,” he explained.

"Solar storms were more common and more intense earlier in solar history – happening all the time, stripping away lots of atmosphere from the planet,” echoed Jim Green, the director of planetary science at NASA headquarters. It's an exciting finding that “will help us understand how atmospheres everywhere interact with their stars,” Green added.

Today, the planet loses atmosphere at a relatively slow rate, approximately 100 grams or a quarter of a pound per second.

“At the current rate of escape, [Mars] would lose its entire atmosphere in a couple of billion of years,” Jakosky said. But there's gas trapped in the polar caps, as well as other areas on the planet, he said, so even billions of years from now, it's not likely to lack an atmosphere entirely. “As we lose gas to space we think it is probably being replenished by other [gas reservoirs on the planet]," he said.

The ancient Martian surface was much warmer than it is now and was better able to support liquid water, scientists believe. Over time, atmosphere loss created the colder, drier planet we see today.

“We still know little about the history of the Red Planet as a whole, its life and climate, and if there was life, what it looked like,” Jakosky said.

MAVEN's data primarily comes from solar storm events that occurred around Christmas 2014 and again in March 2015. The spacecraft has orbited Mars since late 2014 in order to study how and why the planet's atmosphere was lost and how that contributed to the planet's ancient climate.

Although space weather does impact Earth today, it's unlikely similar atmosphere loss would occur here, Jakosky said, because of Earth's strong magnetic field and the decreasing power of solar winds as the solar system ages.

In September, NASAof intermittent liquid water on the surface of the planet, based on images from theMars Reconnaissance Orbiter, which has been collecting Martian data since 2011.This finding fueled speculation about the Red Planet's ability to foster life and when — if ever — NASA might send a manned mission to Mars.

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As part of its investigation of 'Victoria Crater,' Opportunity examined a promontory called 'Cape Verde' from the vantage point of 'Cape St. Mary,' the next promontory clockwise around the crater's deeply scalloped rim. (NASA/JPL-Caltech/Cornell)