The planet we have looked at hardest, and still cannot answer the main question about. Where it is right now, how big and how heavy, what goes round it, and what is still unexplained.
Turning here at one rotation every 12 seconds, which is 7,387 times real speed. What is not sped up: which way it turns, how far the axis leans, and how its day compares with every other planet's. Every dark patch is a named albedo feature at its real place and size: Syrtis Major the dark wedge, Acidalia in the north, Mare Cimmerium and Mare Sirenum along the south. Hellas is the bright circle — it is a 2,300 km basin full of dust, not a dark plain. Olympus Mons and the three Tharsis Montes are in their real diagonal line.
Sun, August 9, 2026
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Distances from the sun are in AU — one AU is the Earth’s average distance, 149,597,870 km — and the angle is where the body sits around its orbit, measured from the March equinox direction.
The mass is worked out from Mars’s gravitational parameter and the gravity from that and its radius; the year comes from Kepler’s third law and the width is the same figure the simulator draws with. None of them is typed in beside the picture, so none of them can disagree with it.
Mars has 2 confirmed moons. Every distance and period here is real, and they are not independent: each pair has to satisfy Kepler’s third law against Mars’s mass, which is how this table is checked rather than trusted.
| Moon | Distance | Orbit | Width | |
|---|---|---|---|---|
| Phobos | 9,376 km | 7.7 h | 22.4 km | Closer to its planet than any other moon in the solar system, and falling |
| Deimos | 23,463 km | 1.26 d | 12.4 km | So small and so far out that from Mars it is barely more than a bright star |
↺ marks a moon going round backwards. Watch this system move →
The table above has every figure — how far out, how long a lap takes, how wide. What follows is what those figures cannot tell you: what each one is actually like, who found it and when, and what is still argued about it.
The doomed one. It orbits below the height at which a Martian day and an orbit take the same time, so tides are dragging it DOWN rather than pushing it out.
Is it a captured asteroid or debris from a giant impact on Mars that re-accreted? Its spectrum says asteroid; its near-circular equatorial orbit says debris. Both cannot be right.
It is spiralling in about 1.8 cm a year. Whether it hits Mars in roughly 50 million years or is torn into a ring first depends on how strong that rubble pile is — which nobody has measured.
The quiet one, and the opposite case: it orbits outside the synchronous height, so it is drifting slowly away, as our own moon is.
Both planets are moving, so the gap between them swings enormously — and the closest approaches are not all equal, because the orbits are ellipses rather than circles. These are the next four, solved from the orbits rather than looked up, and the widest is 1.6× the distance of the closest.
Click a date to take the simulator there. These are minimum-distance moments, which fall near — but not exactly on — opposition.
A rocket cannot point at Mars and fire. It has to leave Earth on an orbit around the sun whose far side touches Mars’s orbit — half an ellipse — and it has to leave at the moment when Mars will have arrived at that far side by the time the ship gets there. That is what a launch window is, and it is why they come round only every 25.0 months.
Set Launch to: Mars on the rocket launches page to see the ellipse, where Mars is on launch day, and where it will be on arrival. Click the date to fly it.
It is a minimum-energy transfer: the cheapest possible path, half an ellipse with Earth’s orbit at one end and the target’s at the other, solved against where the planets really are — so the arrival lands on the planet’s real distance from the sun and its real position on the day it gets there, not on a circle standing in for its orbit.
It is not a mission plan, and three things are left out on purpose. The orbits are treated as flat, so the real inclinations — Mars is tilted 1.85°, Jupiter 1.3° — cost a plane change this ignores. Real missions trade fuel for a faster arrival, so they leave within days or weeks of these dates rather than exactly on them. And anything going past Jupiter usually steals speed from a planet on the way instead of buying it with fuel, which changes both the date and the path.
What it gets right is the thing worth teaching: why the window exists, why it comes round on the cadence it does, and why the cost of the trip is set by where two planets happen to be rather than by how far apart they are.
Every one of these is genuinely unsettled — not simplified for the page, not waiting on a textbook update.
Mars had standing water, a thicker atmosphere and a magnetic field at the same time that life was getting going on Earth. Perseverance has found organic molecules and mineral textures in Jezero Crater that could be biological or could be ordinary chemistry — a 2025 paper describing 'leopard spot' features in the Cheyava Falls rock set out the case for both. Nothing yet is a confirmed biosignature, and settling it probably requires the samples to come back to a laboratory.
Some was stripped away by the solar wind, which MAVEN has watched happening. Some is thought to be locked in carbonate rock and in the polar caps. The books do not balance yet — and how much is still stored in the crust decides whether the loss was inevitable or reversible.
The northern third is low, smooth and thin-crusted; the south is high, ancient and cratered. One enormous impact, several large ones, or convection inside the young planet — the Martian dichotomy is one of the oldest unexplained features in the solar system.
They look like captured asteroids and are made of similar stuff. But both sit on nearly circular orbits right over the equator, which is very hard to achieve by capture and very natural for moons that formed from a debris disc after an impact. Japan's MMX mission is designed to bring a piece of Phobos back and end the argument.
Findings reviewed August 2026. Space science moves; a date on a finding is part of the finding.
Inward: Earth. Outward: Jupiter. Or go back to the whole system, where every planet is on screen at once.
The date, the zoom, the span, the speed, the layers and any flight path are all in the address bar, so copying the URL shares exactly what is on screen. Set it up above, then take the link — it is the quickest way to hand a class one specific thing to look at.
This one is about the whole system. If the question is where the sun and the moon are from where you are standing — what time the sun comes up, why tonight's moon is the shape it is — that is the Sun, Earth & Moon movement simulator, which has a page for every city and a slider over a day, a week or a month.
Also: the classroom guide · sunrise & sunset by city · moon phase & moonrise · lunar eclipses · how the positions are worked out
Did life ever start there? Mars had standing water, a thicker atmosphere and a magnetic field at the same time that life was getting going on Earth. Perseverance has found organic molecules and mineral textures in Jezero Crater that could be biological or could be ordinary chemistry — a 2025 paper describing 'leopard spot' features in the Cheyava Falls rock set out the case for both. Nothing yet is a confirmed biosignature, and settling it probably requires the samples to come back to a laboratory.
Where did the atmosphere go? Some was stripped away by the solar wind, which MAVEN has watched happening. Some is thought to be locked in carbonate rock and in the polar caps. The books do not balance yet — and how much is still stored in the crust decides whether the loss was inevitable or reversible.
Why are the two hemispheres so different? The northern third is low, smooth and thin-crusted; the south is high, ancient and cratered. One enormous impact, several large ones, or convection inside the young planet — the Martian dichotomy is one of the oldest unexplained features in the solar system.
Where did Phobos and Deimos come from? They look like captured asteroids and are made of similar stuff. But both sit on nearly circular orbits right over the equator, which is very hard to achieve by capture and very natural for moons that formed from a debris disc after an impact. Japan's MMX mission is designed to bring a piece of Phobos back and end the argument.