Binding of Isaac: Rebirth Wiki
Binding of Isaac: Rebirth Wiki
Solar   System
Table dividing line 1.png
Challenge Number
Available Rooms
Item Pool Treasure Room.png: no          Item Pool Shop.png: yes
Boss Mom's Heart.png
Unlock Method

Solar System Defeat Mom's Heart 3 times

Solar System is challenge #6. Isaac starts this challenge with 15►Distant Admiration Distant Admiration, 15►Forever Alone Forever Alone, 15►Halo of Flies Halo of Flies, and 15►Transcendence Transcendence. Isaac will also be blindfolded. The goal is to defeat Mom's Heart. This Challenge is available after unlocking Transcendence.


  • As Isaac is blindfolded, Isaac cannot use tears, and must rely entirely on Distant Admiration, Forever Alone, and bombs to deal damage.


  • Because Isaac starts with 3 Fly items, he will also begin the challenge as Beelzebub. This allows Isaac to amass a large number of friendly flies on the Basement floors.
  • The orbiting attack flies can be quite powerful, especially Distant Admiration when used properly. This will require optimization of Isaac's movement to maneuver into position to deal damage, as the flies are constantly moving, and avoid damage simultaneously.
    • Added in Afterbirth †Duct Tape Duct Tape can fix the position of the flies around Isaac, somewhat alleviating this.
  • Enemies that explode on death should only be targeted with Forever Alone, as destroying them with Distant Admiration will result in Isaac getting caught in their explosions.
  • Shops can carry 15►BFFS! BFFS! and 15►Hive Mind Hive Mind, the former of which affects the damage of the orbiting attack flies and the latter of which affects the damage of the blue flies spawned from Beelzebub as well as the size of the orbiting attack flies.
  • 15►Broken Watch Broken Watch and 15►Stop Watch Stop Watch are good items to buy since they slow enemies down.
  • Obtaining 15►Gnawed Leaf Gnawed Leaf makes the challenge trivial as Isaac's orbiting flies still deal damage while Isaac is invulnerable. Obtaining it is highly unlikely, however, since there is no treasure room present.
  • Obtaining 15►Ball of Bandages Ball of Bandages or 15►Cube of Meat Cube of Meat grants a full circle of projectile-blocking orbitals around Isaac.
    • Collecting two cubes of meat grants you a tear-shooting homie, that is not affected by the blindfold.
    • Obtaining 15►Book of Revelations Book of Revelations makes The Harbingers easier to find, allowing Cube of Meat and Ball of Bandages to be found more often.
  • Removed in Afterbirth It is not advised to reshuffle Isaac's items. As this will not remove Isaac's Blindfolded status, it is possible to reroll items in such a way that the run can no longer be completed.
  • Obtaining the Rune of Algiz, Chaos Card Chaos Card or 15►The Bible The Bible can make killing Mom and Mom's Heart/It Lives! much easier.
  • Devil room deals such as 15►Brimstone Brimstone, Added in Afterbirth15►Maw of the Void Maw of the Void, and 15►Mom's Knife Mom's Knife will be ineffective, because of the blindfolded status.
    • Added in Repentance 15►Maw of the Void Maw of the Void now functions despite the Blindfolded status, making this a very valuable item for the challenge.
  • Removed in Afterbirth15►The Boomerang The Boomerang is a useful purchase from the shop as it has a chance to freeze enemies, allowing Isaac to safely use the attack flies against them for the duration of the freeze.
  • Transcendence and other flight items are useless in this challenge because the Beelzebub transformation grants flight by default.
  • Obtaining 15►Bob's Brain Bob's Brain can be handy for defeating bosses, due to its damage and poison effect. It can also be used to break poop or golden poop to gain health, coins, or bombs.
  • Added in Afterbirth †Extension Cord Extension Cord electrifies the orbiting flies, dealing extra damage and destroys fireplaces and poops.
  • Added in Afterbirth15►Black Powder Black Powder helps damage non-flying enemies and bosses.
    • Added in Repentance Black Powder is now effective on all enemies and bosses.
  • Added in Afterbirth15►Incubus Incubus acts as a replacement for Isaac's tears, thus indirectly removing Isaac's Blindfolded status.
  • Added in Repentance15►Revelation Revelation can charge and fire regardless of the Blindfolded status, providing Isaac with an easy way to deal damage.
  • Added in Afterbirth †15►Pause Pause can be used to almost guarantee victory as you can use it to stun all enemies in every other room. Pairing this with items that increase the amount of charges and you can assure victory.
  • If you see the Sacrificial Altar, do not use it under any circumstances. You will lose both fly familiars, and be effectively unable to do anything.

Unlockable achievements[]


  • The challenge is a reference to the Solar System; Isaac represents the sun and the flies represent planets.

MainPageChallenges.png Challenges MainPageChallenges.png

1. Pitch Black 2. High Brow 3. Head Trauma 4. Darkness Falls 5. The Tank 6. Solar System 7. Suicide King
8. Cat Got Your Tongue 9. Demo Man 10. Cursed! 11. Glass Cannon 12. When Life Gives You Lemons 13. Beans! 14. It's in the Cards
15. Slow Roll 16. Computer Savvy 17. Waka Waka 18. The Host 19. The Family Man 20. Purist
21. XXXXXXXXL 22. SPEED! 23. Blue Bomber 24. PAY TO PLAY 25. Have a Heart 26. I RULE! 27. BRAINS!
28. PRIDE DAY! 29. Onan's Streak 30. The Guardian
Afterbirth †
31. Backasswards 32. Aprils Fool 33. Pokey Mans 34. Ultra Hard 35. Pong
36. Scat Man 37. Bloody Mary 38. Baptism by Fire 39. Isaac's Awakening 40. Seeing Double 41. Pica Run 42. Hot Potato
43. Cantripped! 44. Red Redemption 45. DELETE THIS
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