There is a particular irony in studying other worlds. The farther one looks into space, the more precious Earth appears.
As a planetary scientist, I spend my days thinking about Mars, the Moon and the conditions that make life possible, or impossible. The more closely I study these worlds, the less ordinary our own planet seems. Earth is not simply where we happen to live; it is an extraordinary and delicate success story.
Each Earth Day tends to bring back the same question. Why look outward when there is so much work to be done here at home? Why invest in exploring the Moon or Mars when the urgent task is to protect the only world known to sustain life? It is a fair question, but it rests on a false choice. Space exploration deepens our understanding of Earth. It gives us a clearer, more humble sense of what this planet really is.
Our planet protects us in ways most of us rarely stop to consider. We live beneath a thick atmosphere that absorbs much of the radiation moving constantly through the galaxy. We are shielded by a magnetic field that deflects charged particles before they can do harm. Earth sits at the right distance from the Sun for liquid water to exist, while remaining geologically active enough to sustain a stable environment for life over immense spans of time.
The real significance of Earth’s balance comes into view when it is set beside worlds that lost theirs.
Mars is one such world. Today it is cold, dry and exposed. Yet there is strong evidence that it was once more hospitable, with a thicker atmosphere and liquid water on its surface. Our work at NYU Abu Dhabi has focused on the processes behind Mars’s atmospheric and water loss, and on the possibility that, if life ever emerged there, it may have retreated below the surface.
What makes Mars so important is that it shows habitability can be lost. A planet can change. Its atmosphere can erode. Its protections can weaken. Over time, a world that once seemed welcoming can become hostile.
Mars does not offer a direct forecast for Earth. It does offer a reminder that planetary stability should never be taken for granted. This is one reason studying other planets is also, in a very real sense, a way of studying our own. When we compare worlds side by side, we understand more clearly what makes one habitable, what makes another hostile, and why our own has remained so unusually favourable to life. Space science keeps earthly concerns in frame. It places them in a wider context and, in doing so, brings them into sharper focus.
Human spaceflight reinforces the same lesson. As Artemis missions move towards longer stays around and on the Moon, radiation protection has become one of the defining engineering and biomedical challenges. Once astronauts move beyond Earth’s magnetic shielding, they are exposed far more directly to galactic cosmic rays and solar energetic particles. The farther we travel from Earth, the more obvious it becomes how much this planet has been doing for us all along.
There is also something profoundly human in that experience. Astronauts are not usually people given to sentiment. Many come from scientific, technical or military backgrounds, professions shaped by precision, discipline and control. And yet so many of them, after seeing Earth from space, reach for language that is emotional, even spiritual. They describe a fragile blue world suspended in darkness. They speak of unity, responsibility and the sudden smallness of the divisions we treat as permanent on the ground.
That response matters. It tells us something important about what Earth looks like when it is finally seen in its true setting.
There is a practical lesson here too. The moment we leave Earth, we have to recreate, imperfectly and at great cost, the protections our planet already provides for free. We think in terms of shielding, thermal balance, life support, reliable habitats and the careful management of water and power.
Technologies developed to withstand these extreme conditions often improve resilience here on Earth. Space research has long shaped communications, imaging and remote sensing. Today, work on low-power systems, autonomous operations, advanced materials and resource-efficient life support has implications far beyond spacecraft. These capabilities matter in deserts, remote communities and crisis settings, where water, energy, medical support and infrastructure may all be constrained.
In the UAE, the connection between outward ambition and local scientific capability is becoming increasingly visible. The Emirates Mars Mission continues to deepen our understanding of Mars and its climate history. The country is also building lunar capability, while researchers at NYU Abu Dhabi have developed the Emirates Lunar Simulant, a moon-dust analogue designed to support instrument testing and future lunar missions. This is a national space programme built on sustained scientific infrastructure and long-term commitment.
Perhaps that is the most useful thought to hold on to this Earth Day. In everyday life, Earth can seem vast, divided and inexhaustible. Through the lens of planetary science, it looks very different: a narrow envelope of habitability, a rare and finely balanced world that has, against immense odds, remained hospitable to life.
We should continue exploring space. We should return to the Moon, keep studying Mars, and push further into the solar system. The deeper we look into space, the clearer the central truth becomes. Earth is the condition that makes all our journeys possible.
