June 2, 2023 2:39 pm

Dr. Juliane Gross of Rutgers University, an expert on planetary bodies, answers some questions on the meteorite that hit Mercer recently.

May 26, 2023 2:20 pm EDT | Updated May 26, 2023 2:23 pm EDT

MERCER COUNTY, NJ – It’s been a little more than three weeks since a meteorite fell through the roof of a home in Mercer County. And Patch has continued to receive queries from readers who are interested in this phenomenon.

We contacted Professor Juliane Gross from Rutgers University to answer some questions.


Gross is an Associate professor at the University’s Department of Earth and Planetary Sciences. Her research focuses on investigating the formation and evolution of differentiated planetary bodies and her interests include studying rock types, their chemical and physical condition and the effect of micrometeorite bombardment.

A little background on the meteorite:

On May 8, an object struck a ranch-style home on Old Washington Crossing Pennington Road in Hopewell. The meteorite, which is approximately 4″x 6″ and oblong in shape hit the roof, the ceiling and then fell on the hardwood floor. Although the home was occupied at the time, no injuries were reported, police said. More: Possible Meteorite Strikes Mercer County Home: Police

Experts from The College of New Jersey confirmed that the age of the chondrite meteorite is around 4.56 billion years. More: Confirmed: It Was 4 Billion-Year-Old Meteorite That Hit Mercer Home

The meteorite was handed back to the family, who currently owns it. We asked Prof. Gross a few questions about the meteorite, including its monetary value. Here’s the Q&A:

What can meteorites tell us about the solar system?

  • Depending on what type of meteorite it is (primitive, vs differentiated, etc.) meteorites can tell us everything from early Solar System processes such as early formation of the solar system before planets were formed (i.e., what were the building blocks of planets), to planet formation, to planet surface interactions with the space environment, and planet evolution through space and time.

What’s the importance/value of these space objects in science?

  • They are important in the study of planetary sciences. These rocks are samples that we can analyze in laboratories to extract information for example how old it is (and therefore how old our Solar system is, or the planetary body it came from), what the composition of the early solar system was like, what materials were around billions of years ago that probably impacted Earth. Questions like: where did life coming from? where did the water on Earth coming from? how old is the Solar System? how old is Earth? what were the building blocks of planets including Earth? etc. Earth is a gigantic recycling machine and all the old geologic evidence in the form of rocks has been recycled and turned into new rocks, so we can’t use these to extract the information about early Earth or early solar system history. The only way for us to gain insights into these times that have passed long ago is by studying material that comes from that time period, like tiny time capsules from the Solar system’s past.

The family that found the Hopewell meteorite said it was hot when it crashed through the roof. What does that mean?

  • When meteorites fall though Earth’s atmosphere, they create friction and that friction will cause melting of the rock on the outside. That is what we call fusion crust. If you find a meteorite right after it fell it can be warm since rocks are bad conductors of heat. But that also means that only the first mm or so of the rock is warm (not hot) and the inside in fact is as cold as outer space. It is a very big misconception that meteorites are hot after they fall.

The meteorite that fell in Hopewell has been identified as a chrondrite meteorite. How rare are these and what’s the most interesting bit about this kind of meteorite?

  • Ordinary chondrites are the most common type of meteorites that we find. They make up about 96 percent of all meteorites. Chondrites are rocks from asteroids in the Solar System and therefore can teach us about the formation of planets in an early stage.

Physicists from the College of NJ said meteorites rarely fall in a populated area. How rare is this phenomenon?

  • Meteorites fall all over the planet, randomly. Most land in the oceans, since our planet is 73 percent covered by water. If meteorites fall at night, most people sleep and thus won’t see it. Most rocks are also too small to make it intact though the atmosphere and burn up before touching the ground (which we then observe as “shooting stars”). But they do fall randomly without preference for or against an area.

One question we get often from readers is – what’s the monetary value of this meteorite?

  • Ordinary chondrite, like this meteorite, do not really have any commercial value (monetarily). They have scientific value because they are time capsules that we can use to study processes and answer questions that we can’t otherwise access.

The family that owns it – what options do they have? What can they do with the meteorite?

  • There are lots of options – they could donate it, or part of it, to a museum or university; they could have it classified, in which case they need to donate some part of it for science; they could keep it and show it off.

Have a correction or news tip? Email sarah.salvadore@patch.com