" Deep mysteries lurk below (and even above) Mercury’s surface""
or
How does Mercury exist? The more we learn, the more confusing this little world appears.
Mercury is the unloved planet of our Solar System, a barren rock too small and too near the Sun to be interesting. At least, that’s what we thought until we took a closer look and discovered everything about this plain little planet breaks our initial models for how it formed.
Mercury is a hard planet to observe. It’s so close to the Sun that Earth-based telescopes are easily blinded by the star, and locked in orbital resonance that leaves us peering at the same patch of rocks over and over. Even sending spacecraft to investigate is a problem, with probes speeding up as they fall down the gravitational well towards the Sun. It took looping around Venus for Mariner 10 to slow down and redirect into Mercury flybys in the mid-1970s, and the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) probe needed to make an even more elaborate dance to slip into orbit in 2011.
The challenges of observing Mercury pair with its apparent simplicity to leave it frequently overlooked in favor of more dynamic planets. It’s slightly larger than Earth’s Moon, so scientists assumed it was another cold, dead, and dull cratered world without much to offer to our understanding of the story of planetary formation.
Mercury’s distinguishing characteristic is that it is unusually dense for its size, so dense that it must have an massive metallic core. The core is dramatically disproportional to those found within other terrestrial planets, over half of the planet’s volume while Earth’s is less than 10%. Scientists theorized that it originally formed as a larger planet similar to the Earth and Venus, and either had a major collision strip it of much of its crust (akin to the theory of how Earth gained its Moon), or that it's close proximity to a younger, hotter Sun boiled the crust and vaporized lighter elements.
During its flybys, Mariner 10 mapped a series of long, tall cliffs called scarps and a series of wrinkled folds. Paired with the knowledge that Mercury has an unusually large core, scientists theorized that the planet’s surface crumpled as the core cooled and condensed over billions of years.
If Mercury truly does have a hot, liquid core and is geologically active today, every time the crust moves to create a new ridge or wrinkle, a quake releases seismic waves propagating through the planet. On Earth, we detect that seismic energy with seismometers, observing the speed and distribution of the waves to map the planet’s interior. Astronauts did the same thing on a smaller scale during the Apollo missions, observing moonquakes to understand what was going on below the surface. Scientist are planning to apply the same trick on Mars, sending a seismometer on NASA’s delayed InSight lander to peer into the interior or Mars. This same idea could work on Mercury, with observations of seismic waves pinning down the true size and structure of the core, and detecting if, like the Earth, it has a warm liquid outer core around a solid interior.
And if we can do that? We’ll be one step closer to understanding how Mercury formed, why it is the way it is today, and what to expect of other rocky planets around distant stars.
for more learning stay tunned with me and this collection .will Let you know soon.
or
How does Mercury exist? The more we learn, the more confusing this little world appears.
Mercury is the unloved planet of our Solar System, a barren rock too small and too near the Sun to be interesting. At least, that’s what we thought until we took a closer look and discovered everything about this plain little planet breaks our initial models for how it formed.
Mercury is a hard planet to observe. It’s so close to the Sun that Earth-based telescopes are easily blinded by the star, and locked in orbital resonance that leaves us peering at the same patch of rocks over and over. Even sending spacecraft to investigate is a problem, with probes speeding up as they fall down the gravitational well towards the Sun. It took looping around Venus for Mariner 10 to slow down and redirect into Mercury flybys in the mid-1970s, and the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) probe needed to make an even more elaborate dance to slip into orbit in 2011.
The challenges of observing Mercury pair with its apparent simplicity to leave it frequently overlooked in favor of more dynamic planets. It’s slightly larger than Earth’s Moon, so scientists assumed it was another cold, dead, and dull cratered world without much to offer to our understanding of the story of planetary formation.
Mercury’s distinguishing characteristic is that it is unusually dense for its size, so dense that it must have an massive metallic core. The core is dramatically disproportional to those found within other terrestrial planets, over half of the planet’s volume while Earth’s is less than 10%. Scientists theorized that it originally formed as a larger planet similar to the Earth and Venus, and either had a major collision strip it of much of its crust (akin to the theory of how Earth gained its Moon), or that it's close proximity to a younger, hotter Sun boiled the crust and vaporized lighter elements.
During its flybys, Mariner 10 mapped a series of long, tall cliffs called scarps and a series of wrinkled folds. Paired with the knowledge that Mercury has an unusually large core, scientists theorized that the planet’s surface crumpled as the core cooled and condensed over billions of years.
If Mercury truly does have a hot, liquid core and is geologically active today, every time the crust moves to create a new ridge or wrinkle, a quake releases seismic waves propagating through the planet. On Earth, we detect that seismic energy with seismometers, observing the speed and distribution of the waves to map the planet’s interior. Astronauts did the same thing on a smaller scale during the Apollo missions, observing moonquakes to understand what was going on below the surface. Scientist are planning to apply the same trick on Mars, sending a seismometer on NASA’s delayed InSight lander to peer into the interior or Mars. This same idea could work on Mercury, with observations of seismic waves pinning down the true size and structure of the core, and detecting if, like the Earth, it has a warm liquid outer core around a solid interior.
And if we can do that? We’ll be one step closer to understanding how Mercury formed, why it is the way it is today, and what to expect of other rocky planets around distant stars.
for more learning stay tunned with me and this collection .will Let you know soon.
