Basically, you would have about ten seconds of consciousness in varying states of agony, and be dead within a minute.

Depends on the Planet and its atmosphthere, anywhere from a second or less , up to, untill you die from lack of food or water’ !! If you had food, water and shelter ,you could survive until you died of old age !

If you hold your breath, you can survive on Mars without spacesuit for four minutes (hence the fourth planet and four letters in its name). But the boy in the movie Mars Needs Mom is totally fine on Mars without a spacesuit (and he’s breathing fine despite a lot of CO2 and lack of oxygen and doesn’t even harm him!!).

In this solar system other than Mars the hatch wouldn’t finish opening and I’d be dead. But Mars if I take a deep breath and hold it I might last 20 or 30 seconds after the hatch is open. But the good thing about it if I was up there I wouldn’t be so stupid as to test it.

Since all of the other planets (and moons) in our solar system are lethal for different reasons (no atmosphere, thin atmosphere, toxic atmosphere, crushing atmosphere, crushing gravity) you would die in a few microseconds to a couple of minutes on all of them.

Now, can I say we would be dead before arriving at any planet? Let’s say we want to travel to a planet that is only a hundred light years away. 100 X 12,000 = 1,200,000 years to get there. We be dead. Different planets would take even longer. We would never even see a planet. We ain’t going to no planets. They are too far away if we leave the solar system.

By survive I assume you mean still alive 1: Mercury. alight side a few seconds, night time side about 3 minutes but you will be effectively dead with 30s. 2: Venus. Less than a second. 3: Mars: About 3 minutes but you will be effectively dead with 30s. 4: Jupiter, Saturn, Uranus and Neptune don't have solid surfaces so you can’t be ON it.

You don’t survive at all. The moment you leave safety of rocket without suit would be the moment you start to die.You will have a 10–20 sec of consciousness at the maximum then your consciousness shuts down for good. Unless you are returned to safety within 1 to 3 minutes it is good chance you will die. On Venus or on by sun lighted surface of Mercury you would be dead very fast even in spacesuit- in seconds even if you are returned to safety fast. don’t expect to survive many seconds on gas giants, even if you are at height where the pressure is 1 bar.

This depends on the planet. If it is Earthlike, with similar oxygen and gravity, you’d survive as long as one might expect on Earth given multiple factors are met (food, water etc). If we’re talking on planets like Mars, not very long at all. Most rocky planets simply do not have sufficient oxygen levels and thus you wouldn’t survive very long. Gas giants are even harder to determine. The ones in our solar system you’d die after a few seconds due to extreme cold, and provided you somehow survived that, you’d suffocate. If by chance you were lucky enough to end up in an oxygen pocket (which do exist in all of our gas giants) and were able to breathe, you’d die from being crushed after a few minutes of falling due to extreme gravity and pressure.

Surviving on different planets without a space suit. Reading through the other answers for this question all very good for other planets in this solar system. Poor Pluto didnt make the cut again. Thing is the person asking the question asked about planets in general. In our galaxy alone we are talking billions. Some may even have environments better than earth. We could possibly live for hundreds of years though there would most likely be a species already there unwilling to share. Talk about a border wall.

Not bloody very (except of course on Earth). Different atmospheres, or in the case of Mercury negligible atmosphere, and for the most part temperatures well beyond the survivable range of Earthly life (the warmest parts of Mars may be an exception to the latter). The worst case would be Venus—hot enough to melt zinc, and with an atmospheric pressure 90 times that of Earth. A human body would be crushed almost instantly, and reduced to a shriveled ingot.

Honestly, it all depends on how fast you asphyxiate, and where on that planet you are. If, for example, you’re 30 miles up on Venus, you’ll last until you pass out and die from lack of oxygen. If you’re on the surface, you’ll be broiled and crushed by the atmosphere, pass out and die from lack of oxygen…and burning…and crushing. Mercury, Mars, Pluto, Ceres, you’ll last until you pass out and die from lack of oxygen, which won’t take long as air pressure is zero or near zero on all those. Sure, there’s different temperatures and gravities and radiation and whatnot…but you’ll die from lack of oxygen before those have a chance to kill you. The gas giants…similar to what happens on Venus, minus the broiling.

For Mercury, you'd be lucky to survive for as long as you could hold your breath. If you're on the day side, you'll burn, on the night side you'll freeze. Venus, well, assuming you survive the landing without being crushed or burned, you'll have to deal with the acid rain, the immense pressure and heat, i doubt you'd even last long enough to hold or until you'd need to breathe again. Mars, aside from the cold, would probably be your best bet, since there's no oxygen and its far enough away from the sun to not burn you immediately, this one, you're probably safe until you suffocate. I wouldn't hold out too much hope of surviving very long on any of the had giants, they're extremely windy and cold. That almost leaves your last chance, I'm including Pluto to be charitable. Pluto is extremely cold and at present does not currently have an atmosphere (it goes away and comes back dependant on its distance from the sun) if you don't flash freeze, you might survive long enough to suffocate.

I must disagree with several answers here. The worlds (I’m including more than just planets) of our solar system can be divided into 5 categories:

1. Earth—you know the answer here.

2. Airless bodies or nearly so (this includes Mars)—in all cases the result is the same, the air goes rushing out of your lungs. You get 10–15 seconds of consciousness and then a few minutes in which you could be saved if you were brought back into atmosphere in time. Most of these worlds have major temperature extremes but that’s not instantly lethal by any means. You would die of suffocation before freezing or baking.

3. Bodies with hot, high pressure atmospheres (Venus.) Here the air comes smashing into your lungs, once again you no longer have an oxygen reserve and get 10–15 seconds of very painful consciousness. The damage is lethal, there can be no rescue. In this case it’s more questionable what your cause of death is.

4. Bodies with cold, high pressure atmospheres (Titan.) You can survive as long as you can hold your breath. Yes, it’s exceedingly cold but for a short time exceedingly cold atmospheres are not going to inflict appreciable harm. This isn’t that much more severe than cryotherapy (which can involve up to 2 minutes in rooms as cold as you can still have oxygen to breathe. The most exposed bits are sheltered and your feet are covered, but otherwise you wear the minimum needed for modesty), you’ll take some damage to your feet and probably a bit of frostbite on the edges, but it’s nowhere near lethal damage.

5. Gas giants. This is more problematic as you don’t have a surface to step out onto so there isn’t one answer to the question. Sufficiently high up you have case 2. As you go deeper it becomes more like case 4 (but note there’s no surface to stand on, thus no special damage to your feet.) Deeper still it becomes more like case 3, eventually reaching the point your lungs explode (hydrogen + oxygen is quite energetic) as the atmosphere smashes in, eventually you reach a point the heat kills before the lack of oxygen.

I don’t agree with all of those. The gas planets don’t have surfaces so presumably you could drop out of a balloon airlock at the latitude of your choice. Same goes for Venus. If you step outside at the level when the temperature is above freezing but far below boiling you will fall for several minutes before lack of oxygen renders you unconscious. Heck the Galileo Probe lasted over 60 minutes falling on a parachute, you should last at least 5 minutes before pressure and lack of oxygen render you irredeemably dead. So I say it depends on how well you hold your breath but probably two minutes of consciousness on Jupiter as you fall. If you take a simple scuba tank you could even last falling long enough for the pressure to crush you instead, say 15 minutes. Now if you are on the surface of any of the large moons or other planets than Earth you will die very quickly, from instantly on Venus to about a minute on Mercury/Luna/Mars/Ceres or the large planet moons. Your longest survival time on any of those would be Titan around Saturn where the atmospheric pressure would keep you alive but the freezing temperature would kill and unprotected person within a minute or two because breathing that freezing gas would damage your lungs. You can even do that on Earth in places like Antarctica and Titan is far colder than Antarctica. However the question specified a “space suit” so if you bundled up in Arctic class protective clothing and brought a scuba tank you would probably last a few minutes on Titan before the temperature overwhelmed your body heat and gave you hypothermia. I think most of the folks who answered before me did not employ their imaginations very effectively. Survival is not just a matter of conditions in one spot. After all if you take someone out of the tropical jungle and instantly drop them on the Greenland ice sheet hundreds of miles from help they will die very quickly, and Earth is a friendly place to live compared to the rest of the solar system. The trick is to look for places on each body where you survive longest, not shortest. Heck with a big enough air tank and a balloon to keep you floating at the right altitude you live until you die of thirst or run out of air on Venus, Jupiter, Saturn, Uranus or Neptune.

Let's go through the list of planets: Mercury- little to no atmosphere. You would last between 30 to 90 seconds before blacking out due to a lack of oxygen. Venus- Death would be instant. The heat would incinerate you, the pressure would crush you, and the acidity would vitrify you. Venus' atmosphere is just awful. Earth- about 80 years, give or take 20. This has more to do with genetics, where you live, your standard of living, and how lucky you are. Mars- while there is an atmosphere, the pressure is so low that you wouldn't survive more than a minute or two. Like Mercury, you'd blackout within a minute from lack of oxygen. Jupiter- it would all depend on where you were in the atmosphere, but even then, you'd die pretty quickly. If you are high up, you'd die the same way you do on Mercury or Mars. Too far down and you'd be crushed to death. Where the atmosphere has a pressure similar to Earth, you'd asphyxiate due to lack of oxygen and freeze. Saturn, Uranus, and Neptune- same as Jupiter. All the dwarf planets would be similar to Mercury and Mars, with the addition of freezing as well. All the moons (save for two) would be similar to the dwarf planets. The two exceptions are Io around Jupiter and Titan around Saturn. With Io, you would actually be incinerated as the surface is molten for the most part (there are a few places where this is not the case, but you'd die like you would on Mars). Titan would be the longest place you could live after Earth, if you are good at holding your breath and dealing with the cold. You could probably last a few minutes before running out of useful air or freezing to death (Titan's atmosphere is thicker than Earth's, but not fatally so, so you could hold a breath there. It is really cold (less than -100 degrees Celsius or Fahrenheit), so you'd freeze quickly). While you could live a few minutes, you'd be in agony the entire time. So, if you plan on going anywhere in the solar system, bring that space suit.