SUNSET: 
Not From Around Here
NASA’s rovers have found meteorites on Mars that came from elsewhere. What secrets do they hold about Martian history and climate?
Venus Is Dead. Long Live Venus.
In which I attempt a contrarian argument against my own contrarian argument.
Mars Coughs Up Another Mystery
What’s behind the strangely fluctuating levels of oxygen on the Red Planet?
A Fitting Apollo Monument
Fifty years after the fact, the National Mall hosts a spectacular, and deeply moving, celebration.
Sea Change on Venus
Tidal drag from a putative ocean might have helped cool our sister planet for billions of years.
Can a Planet Think? The Gaia Hypothesis, Rethought
Humans have irrevocably changed the planet. Have those processes gone so far that Earth’s biosphere has begun to resemble a human brain?
One Small Step for Plantkind
With a seed germinated on the lunar farside, Earth’s biosphere made its first tentative foray into the cosmos.
Sudden Impact: What Greenland's Crater Means for Our Planet's History
The discovery of a recent huge meteor crater beneath Greenland’s ice sheet has reignited a debate over cosmic influences.
Cosmic Relief with David Grinspoon
NASA Renews Interest in SETI
After a long hiatus, NASA gets back into the SETI game with a workshop on “technosignatures.”
Cosmic Relief with David Grinspoon
Clouds: A Nebulous Existence
In David Grinspoon's latest column, he discusses how, for both Venus and Earth, life's last refuge might lie in the clouds.
Cosmic Relief with David Grinspoon
Variations on a Theme: What Do Earth and Pluto Share in Common?
Nature loves to riff on existing motifs, even in the most unearthly of environments.
Cosmic Relief with David Grinspoon
Advancing the SETI Quest
Hope, perseverance, and the courage of their convictions sustain those seeking hints of alien civilizations and advancing the SETI quest.
Cosmic Relief with David Grinspoon
Chipping Away at Exoplanets
Human ingenuity is helping us unlock the secrets of unimaginably distant worlds — exoplanets.
Alien Visitor
The first interstellar object seen entering the solar system is really quite bizarre.
Chasing the Elusive 2014 MU69
New Horizons' next target, 2014 MU69, was hard to find and remains a bear to pin down, but persistence has paid off.
Cosmic Relief with David Grinspoon
Cosmic Communion: A Total Solar Eclipse
Last summer's total solar eclipse provided a profound moment of celestial accord for millions of Americans.
Cosmic Relief with David Grinspoon
My Rock of Ages
On being immortalized far out in the asteroid belt.
Asteroid 22410 Grinspoon: My Rock of Ages
David Grinspoon shares his thoughts on being immortalized far out in the asteroid belt and his namesake, asteroid 22410 Grinspoon.
Cosmic Relief with David Grinspoon
Life Outside the Habitable Zone
What would allow a planet to host life? The habitable zone is often defined as the distance from a star where liquid water can exist on a planet's surface.
Cosmic Relief with David Grinspoon
Not Venus Again
Once more, NASA leaves our sister planet out of the mix of new missions. Ouch.
