Would you like to work in the United States? I do not know what your specific answer is, but according to a Gallup poll more than 165 million adults in 148 countries would shout a resounding ‘YES’.Mexicans are statistically the largest segment of immigrants trying to come to the USA for employment. That is why the American government has maintained a system of fencing, lighting, sensors, cameras and radars to keep out job-hungry immigrants, terrorists and smugglers.
At what cost?
The cost of a 1058 km double layered fence along part of the US’ 3000 km border with Mexico over the next 20 years is $6.5 billion. Still, Americans are complaining about the poor performance of such measures.
And they indeed have a reason to complain. Why should they voluntarily share their prosperity with someone else? People can claim that they have indeed worked hard to achieve their material prosperity and are not going to share with someone who has not qualified themselves. It is in this light that we should have a cold, calculated Vedic view about our space exploration program.
Here we are, the inhabitants of this earthly planet, trying to expand our frontiers by colonizing other planets in this universe.
Michio Kaku, a prominent American theoretical physicist says, “We’re gonna have an existential shock, looking at the night sky. Realizing that there-there-there are earth-like twins in outer space. And then we’re gonna wonder: Is there anyone looking back?” “I think it’s inevitable that we’re gonna find another intelligent life in outer space. Get used to it.”
So why haven’t they visited or conquered us? 
No one knows, but Kaku says:”There are plenty of uninhabited planets with valuable resources to exploit, so they will likely leave us alone or they might be benevolent since they have had thousands to millions of years to work off their aggressive tendencies. Most likely, we are not on their radar screen. We may be too insignificant for them to make formal contact.”
As far as wisdom found in the Srimad Bhagavatam is concerned, the third reason given by Prof. Kaku is spot on target. Planets above the earth are inhabited by a different form of humans-vastly superior in beauty, strength, knowledge, wealth and fame. They too, like the present-day inhabitants of North America would like to enjoy an opulent lifestyle without wishing to share that with other less-privileged. The Srimad Bhagavatam mentions a particular incident where King Bali tries to usurp the kingdom of Indra and Indra rebukes him with these words – “Those fools and rascals who want to ascend to the upper planetary system by mystic power or mechanical means, or who endeavor to cross even the upper planets and achieve the spiritual world or liberation, I cause to be sent to the lowest region of the universe.”
Srila Prabhupada explains why this is so in his purport –
There are undoubtedly different planetary systems for different persons. As stated in Bhagavad-gita (14.18), urdhvam gacchanti sattva-sthah persons in the mode of goodness can go to the upper planets. Those in the modes of darkness and passion, however, are not allowed to enter the higher planets.
The word divam refers to the higher planetary system known as Svargaloka. Indra, King of the higher planetary system, has the power to push down any conditioned soul attempting to go from the lower to the higher planets without proper qualifications. The modern attempt to go to the moon is also an attempt by inferior men to go to Svargaloka by artificial, mechanical means. This attempt cannot be successful. From this statement of Indra it appears that anyone attempting to go to the higher planetary systems by mechanical means, which are here called maya, is condemned to go the hellish planets in the lower portion of the universe. To go to the higher planetary system, one needs sufficient good qualities. A sinful person situated in the mode of ignorance and addicted to drinking, meat-eating and illicit sex will never enter the higher planets by mechanical means. (purport, Bhag. 8.11.5).
– Syamananda Dasa